Advertisement

CKD Awareness Among US Adults by Future Risk of Kidney Failure

Published:April 15, 2020DOI:https://doi.org/10.1053/j.ajkd.2020.01.007

      Rationale & Objective

      Persons with chronic kidney disease (CKD) are often unaware of their disease status. Efforts to improve CKD awareness may be most effective if focused on persons at highest risk for progression to kidney failure.

      Study Design

      Serial cross-sectional surveys.

      Setting & Participants

      Nonpregnant adults (aged ≥20 years) with CKD glomerular filtration rate categories 3-4 (G3-G4) who participated in the National Health and Nutrition Examination Survey from 1999 to 2016 (n = 3,713).

      Predictor

      5-year kidney failure risk, estimated using the Kidney Failure Risk Equation. Predicted risk was categorized as minimal (<2%), low (2%-<5%), intermediate (5%-<15%), or high (≥15%).

      Outcome

      CKD awareness, defined by answering “yes” to the question “Have you ever been told by a doctor or other health professional that you had weak or failing kidneys?”

      Analytical Approach

      Prevalence of CKD awareness was estimated within each risk group using complex sample survey methods. Associations between Kidney Failure Risk Equation risk and CKD awareness were assessed using multivariable logistic regression. CKD awareness was compared with awareness of hypertension and diabetes during the same period.

      Results

      In 2011 to 2016, unadjusted CKD awareness was 9.6%, 22.6%, 44.7%, and 49.0% in the minimal-, low-, intermediate-, and high-risk groups, respectively. In adjusted analyses, these proportions did not change over time. Awareness of CKD, including among the highest risk group, remains consistently below that of hypertension and diabetes and awareness of these conditions increased over time.

      Limitations

      Imperfect sensitivity of the “weak or failing kidneys” question for ascertaining CKD awareness.

      Conclusions

      Among adults with CKD G3-G4 who have 5-year estimated risks for kidney failure of 5%-<15% and ≥15%, approximately half were unaware of their kidney disease, a gap that has persisted nearly 2 decades.

      Graphical abstract

      Index Words

      Editorial, p. 163
      Chronic kidney disease (CKD) affects ∼15% of the US adult population, and 9 of 10 adults with the disease are not aware of having it.
      • Saran R.
      • Robinson B.
      • Abbott K.C.
      • et al.
      US Renal Data System 2018 Annual Data Report: epidemiology of kidney disease in the United States.
      ,
      Centers for Disease Control and Prevention
      Chronic Kidney Disease in the United States, 2019.
      Although there is some suggestion that patient awareness of CKD may have increased among persons with CKD stage 4 from 2009 to 2016,
      • Saran R.
      • Robinson B.
      • Abbott K.C.
      • et al.
      US Renal Data System 2018 Annual Data Report: epidemiology of kidney disease in the United States.
      numerous studies have found low overall CKD awareness across racially/ethnically and geographically diverse populations.
      • Gasparini A.
      • Evans M.
      • Coresh J.
      • et al.
      Prevalence and recognition of chronic kidney disease in Stockholm healthcare.
      • Dharmarajan S.H.
      • Bragg-Gresham J.L.
      • Morgenstern H.
      • et al.
      State-level awareness of chronic kidney disease in the U.S.
      • Hsu C.-C.
      • Hwang S.-J.
      • Wen C.-P.
      • et al.
      High prevalence and low awareness of CKD in Taiwan: a study on the relationship between serum creatinine and awareness from a nationally representative survey.
      • McClellan W.M.
      • Newsome B.B.
      • McClure L.A.
      • et al.
      Chronic kidney disease is often unrecognized among patients with coronary heart disease: the REGARDS Cohort Study.
      • Flessner M.F.
      • Wyatt S.B.
      • Akylbekova E.L.
      • et al.
      Prevalence and awareness of CKD among African Americans: the Jackson Heart Study.
      • McIntyre N.J.
      • Fluck R.
      • McIntyre C.
      • Taal M.
      Treatment needs and diagnosis awareness in primary care patients with chronic kidney disease.
      It is generally assumed that awareness of disease is an important stimulus for early preventive care, including minimizing nephrotoxic medication use and guiding treatments to slow kidney disease progression.
      • Plantinga L.C.
      • Boulware L.E.
      • Coresh J.
      • et al.
      Patient awareness in chronic kidney disease: trends and predictors.
      ,
      • Plantinga L.C.
      • Tuot D.S.
      • Powe N.R.
      Awareness of chronic kidney disease among patients and providers.
      To date, studies examining this assumption have failed to show robust associations between CKD awareness and blood pressure control, glycemic control, nonsteroidal anti-inflammatory drug avoidance, and general CKD self-management knowledge and behaviors.
      • Devraj R.
      • Borrego M.E.
      • Vilay A.M.
      • Pailden J.
      • Horowitz B.
      Awareness, self-management behaviors, health literacy and kidney function relationships in specialty practice.
      • Whaley-Connell A.
      • Sowers J.R.
      • McCullough P.A.
      • et al.
      Diabetes mellitus and CKD awareness: the Kidney Early Evaluation Program (KEEP) and National Health and Nutrition Examination Survey (NHANES).
      • Tuot D.S.
      • Plantinga L.C.
      • Hsu C.
      • Powe N.R.
      Is awareness of chronic kidney disease associated with evidence-based guideline-concordant outcomes?.
      • Plantinga L.
      • Grubbs V.
      • Sarkar U.
      • et al.
      Nonsteroidal anti-inflammatory drug use among persons with chronic kidney disease in the United States.
      • Tuot D.S.
      • Plantinga L.C.
      • Judd S.E.
      • et al.
      Healthy behaviors, risk factor control and awareness of chronic kidney disease.
      Although these data may temper enthusiasm surrounding diagnostic disclosure of CKD, patient awareness remains an important component of CKD management and preventive care. One argument is that all patients should be aware of all their diagnoses, no matter how consequential, unless they specifically indicate otherwise—and that withholding the diagnosis could represent a paternalistic practice.
      • Daker-White G.
      • Rogers A.
      • Kennedy A.
      • Blakeman T.
      • Blickem C.
      • Chew-Graham C.
      Non-disclosure of chronic kidney disease in primary care and the limits of instrumental rationality in chronic illness self-management.
      In addition, knowledge of CKD diagnosis can reinforce adherence to lifestyle changes and treatments for shared cardiovascular and kidney-related risk factors; patient counseling may be framed in the context of decreasing the risk for worsening kidney function and forestalling or preventing the need for dialysis.
      Controversy surrounding the value of CKD awareness is largely due to the uncertainty of whether CKD progression from early to late stages would be prevented if CKD awareness were greater. Although it would be ideal for all persons with CKD to be aware of their condition, CKD awareness is almost certainly most relevant to those at greatest risk for CKD-specific complications, including the need for kidney replacement therapy. The objectives of this study were to estimate CKD awareness in a nationally representative population sample according to risk for progression to kidney failure and to determine whether awareness has changed over time among those with highest risk for progression to kidney failure.

      Methods

       Study Design

      The National Health and Nutrition Examination Survey (NHANES) is a nationally representative cross-sectional survey of noninstitutionalized US civilian residents that has been conducted continuously since 1999 by the Centers for Disease Control and Prevention’s National Center for Health Statistics. The survey obtains cross-sectional prevalence estimates and when combined over multiple years can identify national trends in disease prevalence. NHANES consists of an interview component, a physical examination component, and a laboratory testing component. The NHANES protocol was approved by the National Center for Health Statistics Research Ethics Review Board (protocol #98-12, #2005-06, #2011-17), and informed consent was obtained from all study participants. We examined data from NHANES from 1999 to 2016.
      Centers for Disease Control and Prevention (CDC), National Center for Health Statistics (NCHS)
      National Health and Nutrition Examination Survey Data.

       Study Population

      Of the 92,062 NHANES participants in 1999 to 2016, our study population included survey participants 20 years or older and who were not pregnant (remaining n = 48,026). For analyses of CKD awareness, we excluded participants with missing data for age, sex, race, serum creatinine level, or urinary albumin-creatinine ratio (UACR) because this information is required for calculation of estimated glomerular filtration rate (eGFR) and estimation of kidney failure risk (remaining n = 42,106). We excluded participants who did not have CKD GFR categories 3 or 4 (G3-G4), as defined by eGFR ≥ 15 and <60 mL/min/1.73 m2 (remaining n = 3,728). Participants with eGFRs < 15 mL/min/1.73 m2 were excluded due to low sample size (n = 97) and inability to differentiate reliably those receiving dialysis from those with advanced but non–kidney replacement therapy–requiring CKD. Finally, we excluded participants who did not answer “yes” or “no” to the question on awareness of CKD (final n for CKD awareness analysis = 3,713).

       Definitions

      CKD G3-G4 was defined by eGFR ≥ 15 and <60 mL/min/1.73 m2, as calculated using the CKD Epidemiology Collaboration (CKD-EPI) equation.
      • Levey A.S.
      • Stevens L.A.
      • Schmid C.H.
      • et al.
      A new equation to estimate glomerular filtration rate.
      The 5-year risk for kidney failure was estimated using the 4-variable Kidney Failure Risk Equation (KFRE), which uses age, sex, eGFR, and UACR to predict risk for kidney failure over time (Item S1).
      • Tangri N.
      • Stevens L.A.
      • Griffith J.
      • et al.
      A predictive model for progression of chronic kidney disease to kidney failure.
      The KFRE is a publicly available risk prediction model initially developed and validated in a retrospective cohort of Canadian patients with CKD; it has demonstrated excellent discriminatory performance in subsequent validation studies using diverse multinational cohorts.
      • Tangri N.
      • Grams M.E.
      • Levey A.S.
      • et al.
      Multinational assessment of accuracy of equations for predicting risk of kidney failure: a meta-analysis.
      ,
      • Peeters M.J.
      • van Zuilen A.D.
      • van den Brand J.A.J.G.
      • et al.
      Validation of the kidney failure risk equation in European CKD patients.
      We categorized KFRE-predicted risk into 4 levels: minimal (<2%), low (2-<5%), moderate (5-<15%), and high risk (≥15%). These cutoffs were selected to represent clinically meaningful risk delineations suggested by prior studies.
      • Tangri N.
      • Stevens L.A.
      • Griffith J.
      • et al.
      A predictive model for progression of chronic kidney disease to kidney failure.
      ,
      • Hingwala J.
      • Wojciechowski P.
      • Hiebert B.
      • et al.
      Risk-based triage for nephrology referrals using the kidney failure risk equation.
      ,
      • Tangri N.
      • Ferguson T.
      • Komenda P.
      Pro: risk scores for chronic kidney disease progression are robust, powerful and ready for implementation.
      CKD awareness was defined among those with CKD as a yes answer to the interview question “Have you ever been told that you have weak or failing kidneys? Do not include kidney stones, bladder infections, or incontinence.”
      For comorbid conditions, hypertension was defined as either systolic blood pressure ≥ 140 mm Hg, diastolic blood pressure ≥ 90 mm Hg, or current use of antihypertensive medication.
      • Crim M.T.
      • Yoon S.S.
      • Ortiz E.
      • et al.
      National surveillance definitions for hypertension prevalence and control among adults.
      If more than 1 blood pressure reading was measured, mean systolic and diastolic values across all readings were used. Diabetes was defined as hemoglobin A1c level ≥ 6.5% or current use of diabetes medication.
      International Expert Committee
      International Expert Committee report on the role of the A1C assay in the diagnosis of diabetes.

       Statistical Methods

      Combining all survey years 1999 to 2016, the proportion of persons aware of CKD was estimated within each risk group. To assess for temporal trends, we examined CKD awareness during 3 consecutive 6-year intervals: 1999 to 2004, 2005 to 2010, and 2011 to 2016. Multiple survey years were aggregated to ensure sufficient cell sizes for analysis within each interval and KFRE risk group. The unadjusted prevalence of CKD awareness was estimated during each interval by KFRE risk group. Temporal trends in CKD awareness were assessed by fitting logistic regression models using interval as a categorical predictor, then using contrasts to test for linear trends in the corresponding coefficients.
      • Vittinghoff E.
      • Glidden D.V.
      • Shiboski S.C.
      • McCulloch C.E.
      Regression Methods in Biostatistics.
      The association between KFRE risk and CKD awareness was examined using multivariable logistic regression, adjusting for demographic variables and comorbid conditions previously associated with CKD awareness. Because the question of whether CKD definition should use an age-adapted eGFR is an issue of current interest,
      • Delanaye P.
      • Jager K.J.
      • Bökenkamp A.
      • et al.
      CKD: a call for an age-adapted definition.
      • Wesson D.E.
      Does eGFR by any number mean the same?.
      • Chertow G.M.
      • Beddhu S.
      Modification of eGFR-based CKD definitions: perfect, or enemy of the good?.
      we also examined whether the association between KFRE risk and CKD awareness varied by age. For this analysis, age was categorized as 20 to 64, 65 to 74, and 75 or more years. Using logistic regression with an interaction term for age and KFRE risk, marginal predictions of CKD awareness were obtained for each KFRE risk group according to age category.
      As a secondary analysis, we compared awareness of CKD with awareness of other common chronic conditions, namely, hypertension and diabetes. For this analysis, hypertension awareness was defined as either self-reported hypertension (defined by answering yes to the question “Have you ever been told by a doctor or other health professional that you had hypertension, also called high blood pressure?”) or self-reported use of prescription medication for high blood pressure among persons with hypertension. Diabetes awareness was defined as either self-reported diabetes (defined by answering yes to the question “Other than during pregnancy, have you ever been told by a doctor or health professional that you have diabetes or sugar diabetes?”) or self-reported insulin or diabetic pill use among persons with diabetes.
      Analyses were performed using Stata/IC, version 15.1 (StataCorp). Adjustments were made to account for historical laboratory creatinine calibration issues according to NHANES analytical guidelines (Item S2). All estimates in NHANES were weighted to the US population using the appropriate sample weights with variance computed accounting for strata and primary sampling units. All reported estimates were based on >8 df, and all had relative standard error < 30%, in accordance with NHANES analytic guidelines and the National Center for Health Statistics Data Presentation Standards for Proportions.
      • Parker J.D.
      • Talih M.
      • Malec D.J.
      • et al.
      National Center for Health Statistics data presentation standards for proportions.

      Results

       Participant Characteristics

      Baseline characteristics of NHANES participants with CKD G3-G4 (n = 3,713) are described in Table 1. Higher KFRE risk was more common among men, persons of nonwhite race/ethnicity, persons with diabetes, and persons with hypertension. Mean eGFR ranged from 52 mL/min/1.73 m2 in the minimal KFRE risk group to 26 mL/min/1.73 m2 in the highest risk group; median UACR ranged from 9 to 934 mg/g across these groups of KFRE risk. The proportion of persons with any type of health insurance was high at ∼96% and was similar across all risk groups, although in higher risk groups, Medicaid was more common (14.4% in the highest risk group vs 6.6% in the lowest) and private insurance was less common (48.9% vs 61.2%, respectively).
      Table 1Characteristics of US adults With CKD by Estimated 5-Year Kidney Failure Risk, NHANES 1999-2016
      CharacteristicEstimated 5-y Kidney Failure RiskP
      <2%2%<5%5%-<15%≥15%
      No. of participants2,818423258214
      Mean age, y71 (71-72)73 (71-74)71 (69-73)67 (64-69)0.2
      Women60.4% (58.3%-62.5%)58.6% (53.1%-64.2%)50.5% (44.0%-57.0%)46.7% (38.1%-55.1%)<0.001
      Race/ethnicity<0.001
       Non-Hispanic white84.0% (81.9%-86.0%)74.9% (70.2%-79.6%)71.9% (65.5%-78.2%)57.8% (48.8%-66.8%)
       Non-Hispanic black7.6% (6.4%-8.8%)12.1% (9.1%-15.1%)13.3% (9.2%-17.5%)20.4% (14.5%-26.3%)
       Mexican American2.0% (1.4%-2.6%)3.9% (2.4%-5.3%)4.9% (2.1%-7.7%)8.9% (4.9%-12.8%)
       Other Hispanic3.0% (1.8%-4.2%)2.6% (1.0%-4.1%)3.7% (1.6%-5.9%)3.9% (1.2%-6.6%)
       Other3.5% (2.6%-4.3%)6.6% (3.0%-10.2%)6.2% (2.4%-10.1%)9.0% (2.2%-15.8%)
      Health insurance, any96.3% (95.3%-97.2%)95.5% (92.5%-98.5%)95.3% (92.6%-98.0%)95.0% (90.9%-99.0%)0.8
       Private insurance61.2% (58.3%-64.2%)58.0% (51.7%-64.5%)49.0% (41.2%-56.9%)48.9% (40.4%-57.3%)0.002
       Medicare70.9% (68.3%-73.6%)75.6% (69.9%-81.4%)72.9% (65.5%-80.4%)68.2% (59.9%-76.6%)0.4
       Medicaid6.6% (5.4%-7.8%)11.7% (7.9%-15.4%)12.5% (6.9%-18.0%)14.4% (8.6%-20.3%)<0.001
      Reported a routine site of care96.8% (96.0%-97.6%)96.0% (93.6%-98.5%)97.9% (96.2%-99.7%)98.6% (97.0%-100.0%)0.4
      ≥High school education75.3% (73.0%-77.7%)67.0% (61.3%-72.7%)63.4% (57.5%-70.4%)66.0% (58.6%-73.5%)<0.001
      Current smoker18.7% (15.8%-21.6%)22.6% (15.8%-29.4%)20.3% (11.4%-29.2%)26.4% (16.2%-36.6%)0.3
      Obesity36.2% (34.3%-38.1%)41.7% (34.4%-49.1%)49.5% (41.3%-57.8%)52.0% (43.1%-61.0%)<0.001
      Family history of diabetes39.6% (37.2%-41.9%)43.6% (37.6%-49.7%)43.3% (35.5%-51.0%)61.9% (53.6%-70.2%)<0.001
      Diabetes22.6% (20.7%-24.5%)37.8% (31.6%-44.1%)46.4% (39.5%-53.3%)55.6% (46.2%-65.0%)<0.001
      Hypertension80.3% (77.9%-82.6%)92.4% (88.6%-96.2%)94.8% (91.9%-97.8%)92.9% (87.9%-98.0%)<0.001
      Coronary artery disease12.5% (10.9%-14.0%)18.7% (14.0%-23.5%)22.3% (16.0%-28.6%)27.6% (19.5%-35.7%)<0.001
      Congestive heart failure10.6% (9.1%-12.1%)17.1% (13.0%-21.2%)24.2% (18.2%-30.2%)27.8% (19.9%-35.8%)<0.001
      CKD GFR category<0.001
       G3a84.8% (83.4%-86.3%)19.5% (15.1%-24.0%)7.4% (3.5%-11.2%)0%
       G3b15.2% (13.7%-16.6%)69.0% (63.1%-74.9%)54.6% (47.3%-61.8%)34.2% (25.7%-42.7%)
       G40%11.5% (7.3%-15.7%)38.1% (31.1%-45.1%)65.8% (57.3%-74.3%)
      eGFR, mL/min/1.73 m2
      Mean±standard deviation.
      52 ± 639 ± 833 ± 826 ± 8<0.001
      UACR, mg/g
      Median [interquartile range].
      9 [5-22]41 [13-135]63 [34-330]934 [322-2,763]<0.001
      Note: Values in parentheses are 95% confidence intervals. Reported figures are adjusted for complex survey design used by NHANES to estimate nationally representative results. Obesity defined as body mass index ≥ 30 kg/m2.
      Abbreviations: CKD, chronic kidney disease; eGFR, estimated glomerular filtration rate, calculated by Chronic Kidney Disease–Epidemiology Collaboration (CKD-EPI) equation; NHANES, National Health and Nutrition Examination Survey; UACR, urinary albumin-creatinine ratio.
      a Mean ± standard deviation.
      b Median [interquartile range].

       Proportion Aware of CKD

      Among adults with CKD G3-G4 and <2% KFRE risk, 7.0% (95% confidence interval [CI], 5.9%-8.3%) were aware of their CKD; among those with 2%-<5% KFRE risk, 18.7% (95% CI, 14.0%-23.4%) were aware; among those with 5%-<15% KFRE risk, 43.4% (95% CI, 36.4%-50.5%) were aware; and among those with ≥15% KFRE risk, 49.6% (95% CI, 41.1%-58.2%) were aware.
      Consistently over time, crude prevalence of CKD awareness was higher with higher KFRE risk group (Fig 1A). In analyses of awareness over time, unadjusted analyses showed a borderline statistically significant trend only among those at minimal KFRE risk (6.3% [95% CI, 4.3%-8.3%] in 1999-2004 and 9.6% [95% CI, 7.4%-11.8%] in 2011-2016; Ptrend = 0.03). In other KFRE risk groups, no statistically significant trends were found: CKD awareness estimates in the 2%-<5% KFRE risk group were numerically higher in 2011 to 2016 (22.6%; 95% CI, 14.7%-30.4%) than in 1999 to 2004 (14.6%; 95% CI, 6.6%-22.5%), but this was not statistically significant (Ptrend = 0.2). Awareness in higher risk groups ranged from 42% to 50% (Ptrend = 0.8 and 0.9, respectively).
      Figure thumbnail gr1
      Figure 1Chronic kidney disease awareness by 5-year kidney failure risk, National Health and Nutrition Examination Survey (NHANES) 1999 to 2016. P values reported are for linear trends. (A) End-stage kidney disease (ESKD) risk is the estimated 5-year risk for dialysis or kidney transplantation, calculated using the 4-variable kidney failure risk equation. (B) Estimates are standardized to the 1999 to 2004 age distribution. (C) Adjustment is for sex, race/ethnicity, presence of diabetes, and presence of hypertension.
      Similar results were obtained when analyses were conducted for direct age-standardized CKD awareness (Fig 1B) and then with adjustment for sex, age, race/ethnicity, presence of hypertension, and presence of diabetes (Fig 1C). No statistically significant trends were observed in any KFRE risk groups in either age-standardized or adjusted analyses.

       Association of Kidney Failure Risk With CKD Awareness

      The association between KFRE risk and CKD awareness was examined using multivariable logistic regression (Table 2). In both unadjusted and adjusted models, the odds of CKD awareness were greater with each category of higher KFRE risk. Odds of CKD awareness were similar in the 2 highest risk groups (5%-<15% and ≥15%). Associations between CKD awareness and each KFRE risk group were all statistically significant (P < 0.01 for each).
      Table 2Association of Kidney Failure Risk and CKD Awareness by Multivariable Logistic Regression Among US Adults With CKD G3-G4
      Kidney Failure Risk GroupUnadjusted OR (95% CI)Adjusted OR (95% CI)
      Model 1
      Adjusted for age, sex, and race/ethnicity.
      Model 2
      Adjusted for age, sex, race/ethnicity, hypertension status, and diabetes status.
      <2%1.00 (reference)1.00 (reference)1.00 (reference)
      2%-<5%3.02 (2.11-4.33)3.14 (2.22-4.43)2.76 (1.90-4.01)
      5%-<15%10.10 (7.11-14.34)10.19 (7.04-14.74)9.36 (6.30-13.90)
      ≥15%12.96 (8.76-19.16)11.20 (7.42-16.92)9.24 (5.97-14.31)
      Note: Based on NHANES 1999-2016. Kidney failure risk was 5-year risk, determined using the 4-variable kidney failure risk equation.
      Abbreviations: CI, confidence interval; CKD, chronic kidney disease; NHANES, National Health and Nutrition Examination Survey; OR, odds ratio.
      a Adjusted for age, sex, and race/ethnicity.
      b Adjusted for age, sex, race/ethnicity, hypertension status, and diabetes status.
      Figure 2 shows unadjusted and adjusted CKD awareness by KFRE risk and age categories. Findings were overall similar between unadjusted and adjusted analyses. CKD awareness was greater with increasing kidney failure risk, except among the highest risk group in the 20- to 64-year age category. The 75-year-or-older age category consistently had the lowest awareness across all risk groups. Of note, interpretation of these interactions is limited due to wide CIs, and P values for interaction were nonsignificant in both unadjusted and adjusted analyses.
      Figure thumbnail gr2
      Figure 2Chronic kidney disease awareness by age and kidney failure risk. (A) End-stage kidney disease risk is the estimated 5-year risk for dialysis or kidney transplantation, calculated using the 4-variable kidney failure risk equation. (B) Adjustment is for sex, race/ethnicity, presence of hypertension, and presence of diabetes. P values reported are for tests for interaction.

       Comparison of Awareness of CKD, Hypertension, and Diabetes

      Figure 3 shows trends in awareness of diabetes and hypertension during the study period compared with CKD (all CKD G3-G4) and high-risk CKD (CKD with ≥15% risk for kidney failure at 5 years as determined by the KFRE). From 1999 to 2016, hypertension and diabetes awareness were both consistently higher than CKD awareness in all CKD G3-G4 and in high-risk CKD. During this period, both hypertension and diabetes exhibited an increase in prevalence of disease awareness (Ptrend < 0.001 for both).
      Figure thumbnail gr3
      Figure 3Comparative awareness of chronic kidney disease (CKD), hypertension, and diabetes, National Health and Nutrition Examination Survey (NHANES) 1999 to 2016. (A) P values reported are for linear trends. Diabetes awareness was defined as self-reported diabetes, insulin use, or diabetic pill use among persons with hemoglobin A1c levels ≥ 6.5% or documented diabetes medication use. Hypertension awareness was defined as self-reported hypertension or high blood pressure medication use among persons with systolic blood pressure ≥ 140 mm Hg, diastolic blood pressure ≥ 90 mm Hg, or documented antihypertensive medication use. CKD awareness was defined as reporting having been told by a health provider that one had “weak or failing kidneys” among persons with estimated glomerular filtration rates of 15 to <60 mL/min/1.73 m2 (defining CKD stages 3-4) or ≥15% 5-year risk for dialysis or kidney transplantation, calculated using the 4-variable Kidney Failure Risk Equation (defining CKD with ≥15% end-stage kidney disease [ESKD] risk) respectively. (B) Adjustment is for age, sex, race/ethnicity, presence of diabetes, and presence of hypertension.

      Discussion

      In this nationally representative sample of US adults, we found that although CKD awareness was higher among persons with higher 5-year kidney failure risk, approximately half the participants with ≥15% risk for developing kidney failure within 5 years were unaware of having kidney disease. Additionally, no statistically significant trends over time were observed in CKD awareness for any risk groups except among those with minimal-risk CKD, but this trend was not significant in adjusted analyses. After adjustment for demographic factors and comorbid conditions, we found that higher predicted kidney failure risk was associated with increased odds of CKD awareness.
      Our findings that CKD awareness is markedly lower for persons with CKD, even those at the highest levels of risk for kidney failure, compared with all persons with hypertension or diabetes regardless of their future risk for adverse events underscore the need for the Public Awareness Initiative for Advancing American Kidney Health launched by the National Kidney Foundation, American Society of Nephrology, and US Department of Health and Human Services.
      National Kidney Foundation
      Public awareness initiative for AAKH announced as a public-private partnership with NKF and ASN. November 4, 2019.
      This initiative aims to elevate kidney disease awareness and includes an accompanying Kidney Risk Campaign. Additionally, both diabetes and hypertension awareness demonstrate an increase over time with statistically significant Ptrend values. The trend in awareness for CKD G3-G4 was not significant in adjusted analyses. Furthermore, no statistically significant trends were observed in the high-risk CKD group, a group for whom the practical implications of CKD are potentially most clinically relevant.
      There are several possible factors contributing to low CKD awareness. In one study of audiotaped primary care encounters, CKD was less commonly discussed compared with hypertension or diabetes, and most CKD discussions were limited to technical discussion of laboratory results rather than risk factors, prevention, or complications.
      • Greer R.C.
      • Cooper L.A.
      • Crews D.C.
      • Powe N.R.
      • Boulware L.E.
      Quality of patient-physician discussions about CKD in primary care: a cross-sectional study.
      Other possible contributing factors may be provider underrecognition, lack of CKD knowledge or familiarity on the part of primary care providers, and fear of overwhelming patients, as compared with hypertension or diabetes.
      • Greer R.C.
      • Crews D.C.
      • Boulware L.E.
      Challenges perceived by primary care providers to educating patients about chronic kidney disease.
      A somewhat surprising finding was the similarity in CKD awareness between the intermediate- (5%-<15% KFRE risk at 5 years) and high-risk (≥15%) groups. Both categories of risk were associated with approximately 9 times the odds of awareness compared with the minimal-risk group. The decision not to disclose CKD to patients has been attributed at least in part to the view that there is little benefit to CKD disclosure when kidney disease is mild, has no immediate treatment implications, and is likely to cause undue anxiety in patients who are worried they will need dialysis or kidney transplantation.
      • Crinson I.
      • Gallagher H.
      • Thomas N.
      • de Lusignan S.
      How ready is general practice to improve quality in chronic kidney disease? A diagnostic analysis.
      If clinicians’ efforts to notify and educate patients about CKD are related to kidney disease severity, similar rates of awareness between intermediate and high levels of risk would suggest that clinicians are failing to discriminate between these levels of risk in patients with CKD.
      Although persons in the highest risk group had a mean eGFR that was 7 mL/min/1.73 m2 lower than those in the intermediate-risk group (33 vs 26 mL/min/1.73 m2), they had substantially more albuminuria (median UACRs of 934 vs 63 mg/g). Prior studies have shown proteinuria to be an uncommon reason for nephrology referral, suggesting that a possible reason that clinicians fail to recognize high-risk kidney disease may be a relative underappreciation of the prognostic significance of albuminuria compared to eGFR for predicting renal and cardiovascular outcomes.
      • McIntyre N.J.
      • Fluck R.
      • McIntyre C.
      • Taal M.
      Treatment needs and diagnosis awareness in primary care patients with chronic kidney disease.
      ,
      • Hingwala J.
      • Wojciechowski P.
      • Hiebert B.
      • et al.
      Risk-based triage for nephrology referrals using the kidney failure risk equation.
      Risk assessment using KFRE would reinforce the importance of albuminuria measurement and allow clinicians to assess risk more effectively and objectively for patients with CKD. KFRE use in primary care could help risk-stratify patients with CKD and inform appropriate counseling, as well as next steps in workup and referral.
      • Hingwala J.
      • Wojciechowski P.
      • Hiebert B.
      • et al.
      Risk-based triage for nephrology referrals using the kidney failure risk equation.
      ,
      • Smekal M.D.
      • Tam-Tham H.
      • Finlay J.
      • et al.
      Perceived benefits and challenges of a risk-based approach to multidisciplinary chronic kidney disease care: a qualitative descriptive study.
      ,
      • Smekal M.D.
      • Tam-Tham H.
      • Finlay J.
      • et al.
      Patient and provider experience and perspectives of a risk-based approach to multidisciplinary chronic kidney disease care: a mixed methods study.
      We found no statistically significant effect modification of age on the association between KFRE risk and CKD awareness. Except in the highest KFRE risk group, CKD awareness was higher in younger age groups. Of the multiple provider-level (recognition and disclosure) and patient-level (eg, health literacy and denial) factors that may affect awareness, the observed findings are suggestive of several possibilities.
      • Plantinga L.C.
      • Tuot D.S.
      • Powe N.R.
      Awareness of chronic kidney disease among patients and providers.
      One possible provider-level factor would be a higher threshold for disclosure for mild CKD at older age. This may be due to a view that kidney disease is a part of normal aging and that labeling or disclosure may lead to undue anxiety and stigma for otherwise well patients.
      • Crinson I.
      • Gallagher H.
      • Thomas N.
      • de Lusignan S.
      How ready is general practice to improve quality in chronic kidney disease? A diagnostic analysis.
      ,
      • Blakeman T.
      • Protheroe J.
      • Chew-Graham C.
      • Rogers A.
      • Kennedy A.
      Understanding the management of early-stage chronic kidney disease in primary care: a qualitative study.
      ,
      • Abdi Z.
      • Gallagher H.
      • O’Donoghue D.
      Telling the truth: why disclosure matters in chronic kidney disease.
      This behavior, regardless of whether intentional, is much in keeping with the recent conversation surrounding whether the eGFR-based definition of CKD should be age-adapted, based on physiologic age-related kidney function decline and examination of age-dependent differences in mortality risk associated with eGFR.
      • Delanaye P.
      • Jager K.J.
      • Bökenkamp A.
      • et al.
      CKD: a call for an age-adapted definition.
      • Wesson D.E.
      Does eGFR by any number mean the same?.
      • Chertow G.M.
      • Beddhu S.
      Modification of eGFR-based CKD definitions: perfect, or enemy of the good?.
      In particular, it has been suggested that the threshold eGFR for CKD definition should be higher with younger age (75 mL/min/1.73 m2 for age < 45 years) and lower with older age (45 mL/min/1.73 m2 for age > 65 years).
      Another possibility is whether providers are underrecognizing CKD in older age groups, which is plausible if older individuals are more likely to have creatinine tested for reasons other than kidney health, thereby leading to incidental detection of CKD. Additional study would be needed to discern the extent to which age-related differences in provider recognition versus disclosure (vs patient-level factors) lead to different rates of CKD awareness. However, these findings should be interpreted with caution given the uncertainty associated with awareness estimates due to small sample sizes in higher KFRE risk groups.
      This study benefits from capturing a nationally representative population over an extended period spanning 18 years. It also represents use of the KFRE as a method to stratify our analysis based on each person’s risk for a meaningful clinical outcome, rather than stratifying by disease definitions such as CKD stage or albuminuria, which are not as directly patient-centered. Our study examined the CKD population through a lens of predicted risk rather than observed outcomes, providing a more coherent and actionable framework for guiding CKD awareness efforts and focusing on persons at high risk for kidney failure. By directly showing low awareness among persons with high predicted kidney failure risk, we define a discrete population—identifiable based on presently obtainable laboratory and demographic information—in which awareness efforts may be intensified. As the basis for risk-based care, this helps further underscore the importance of albuminuria testing for risk stratification to guide referral, counseling, and treatment decisions.
      The primary limitation of this study was the imperfect sensitivity of the question used in NHANES for ascertaining awareness of kidney disease. Ascertainment of CKD awareness among persons with laboratory-defined CKD can differ according to how the question is asked, with the NHANES question referring to “weak or failing kidneys” being relatively less sensitive compared with different phrases to describe CKD.
      • Tuot D.S.
      • Zhu Y.
      • Velasquez A.
      • et al.
      Variation in patients’ awareness of CKD according to how they are asked.
      ,
      • Tuot D.S.
      • Wong K.K.
      • Velasquez A.
      • et al.
      CKD awareness in the general population: performance of CKD-specific questions.
      Clinicians may describe CKD to patients in a variety of ways (eg, weak kidneys, kidney disease, poor kidney function, and protein in the urine), and the best question to ascertain CKD awareness has not been conclusively established. A study has shown that a compound question or combining multiple questions may increase the yield.
      • Tuot D.S.
      • Zhu Y.
      • Velasquez A.
      • et al.
      Variation in patients’ awareness of CKD according to how they are asked.
      However, the present question remains the most readily available way to obtain consistent nationally representative estimates of trends in CKD awareness. Given that improving awareness of kidney disease has been announced in 2019 as a priority of the Advancing American Kidney Health initiative, better validated tools are needed for improved measurement and national surveillance of CKD awareness.
      Additional limitations included small numbers of persons with advanced CKD, which precluded more precise estimation and analysis of CKD awareness in higher risk groups. Because of the cross-sectional nature of NHANES, the diagnosis of CKD was based on a single measurement of creatinine and albuminuria, whereas the gold-standard definition requires 2 abnormal laboratory parameters separated by at least 3 months.
      National Kidney Foundation
      K/DOQI clinical practice guidelines for chronic kidney disease: evaluation, classification, and stratification.
      Similarly, hypertension and diabetes diagnoses may be subject to misclassification due to definitions based on a single time point. Finally, the cross-sectional design does not allow any inference with respect to whether or how kidney failure risk might lead to CKD awareness.
      In summary, we found in a nationally representative sample that approximately half the persons with CKD and high risk for progression to kidney failure (≥15% within 5 years) were unaware of having kidney disease, and among those with minimal (<2%) risk, <10% were aware. The heterogeneity of kidney failure risk also likely contributes to difficulty demonstrating the effects of CKD awareness in the overall CKD population. Future studies of CKD awareness should present risk-stratified results because this may better direct public health efforts. Although there may be some debate about the disclosure of CKD diagnosis for those with milder degrees of CKD and low risk for progression, the finding that such a large proportion of persons with the highest risk for needing dialysis or kidney transplantation within 5 years is unaware of having kidney disease is highly concerning, particularly because awareness in this group remains below that of hypertension and diabetes and has not changed with time. Despite broadly directed efforts by many organizations to raise overall awareness of kidney disease over the years, CKD awareness has remained largely unchanged for 18 years. The 2019 executive order on Advancing American Kidney Health initiative was an unprecedented step in garnering nationwide attention surrounding kidney disease, bringing it directly into the national spotlight. The subsequent announcement of the Public Awareness Initiative, which is to include a nationwide Kidney Risk Campaign, is an exciting and welcome step we should all look forward to with great anticipation.

      Article Information

      CDC CKD Surveillance Team

      University of Michigan: Rajiv Saran (PI), Vahakn Shahinian, Michael Heung, Brenda W. Gillespie, Hal Morgenstern, William Herman, Kara Zivin, Jennifer Bragg-Gresham, Diane Steffick, Yun Han, Xiaosong Zhang, Yiting Li, Vivian Kurtz, April Wyncott; University of California, San Francisco: Neil R. Powe (PI), Tanushree Banerjee, Delphine S. Tuot, Chi-yuan Hsu, Charles E. McCulloch, Deidra Crews, Raymond Hsu, Kirsten Johansen, Michael Shlipak, Janet Canela; Centers for Disease Control and Prevention: Nilka Ríos Burrows (Technical Advisor), Mark Eberhardt, Juanita Mondesire, Priti Patel, Meda Pavkov, Deborah Rolka, Sharon Saydah, Sundar Shrestha, Larry Waller.

      Authors’ Full Names and Academic Degrees

      Chi D. Chu, MD, Charles E. McCulloch, PhD, Tanushree Banerjee, PhD, Meda E. Pavkov, MD, PhD, Nilka R. Burrows, MPH, Brenda W. Gillespie, PhD, Rajiv Saran, MD, Michael G. Shlipak, MD, MPH, Neil R. Powe, MD, MPH, MBA, and Delphine S. Tuot, MDCM, MAS.

      Authors’ Contributions

      Research idea and study design: CDC, TB, MEP, NRB, BWG, RS, MGS, DST, NRP; data acquisition: CDC; data analysis/interpretation: CDC, CEM, DST; statistical analysis: CDC, CEM, DST; supervision or mentorship: DST, NRP. Each author contributed important intellectual content during manuscript drafting or revision, accepts personal accountability for the author’s own contributions, and agrees to ensure that questions pertaining to the accuracy or integrity of any portion of the work are appropriately investigated and resolved.

      Support

      This investigation was supported by the National Institute of Diabetes and Digestive and Kidney Diseases of the National Institutes of Health under the Ruth L. Kirschstein National Research Service Award 1F32DK122629-01, and by the Supporting, Maintaining and Improving the Surveillance System for Chronic Kidney Disease in the U.S., Cooperative Agreement Number, U58 DP006254 , funded by the Centers for Disease Control and Prevention . The funders of this study had no role in study design; collection, analysis, and interpretation of data; writing the report; and the decision to submit the report for publication.

      Financial Disclosure

      The authors declare that they have no relevant financial interests.

      Disclaimer

      The findings and conclusions in this report are solely those of the authors and do not necessarily represent the official position of the Centers for Disease Control and Prevention or the Department of Health and Human Services.

      Prior Presentation

      An earlier version of this work was presented as a poster at the American Society of Nephrology Kidney Week, November 5-10, 2019, Washington, DC.

      Peer Review

      Received September 19, 2019. Evaluated by 2 external peer reviewers and a statistician, with direct editorial input from an International Editor, who served as Acting Editor-in-Chief. Accepted in revised form January 6, 2020. The involvement of an Acting Editor-in-Chief was to comply with AJKD’s procedures for potential conflicts of interest for editors, described in the Information for Authors & Journal Policies.

      Supplementary Material

      References

        • Saran R.
        • Robinson B.
        • Abbott K.C.
        • et al.
        US Renal Data System 2018 Annual Data Report: epidemiology of kidney disease in the United States.
        Am J Kidney Dis. 2019; 73: A7-A8
        • Centers for Disease Control and Prevention
        Chronic Kidney Disease in the United States, 2019.
        US Department of Health and Human Services, Centers for Disease Control and Prevention, Atlanta, GA2019
        • Gasparini A.
        • Evans M.
        • Coresh J.
        • et al.
        Prevalence and recognition of chronic kidney disease in Stockholm healthcare.
        Nephrol Dial Transplant. 2016; 31: 2086-2094
        • Dharmarajan S.H.
        • Bragg-Gresham J.L.
        • Morgenstern H.
        • et al.
        State-level awareness of chronic kidney disease in the U.S.
        Am J Prev Med. 2017; 53: 300-307
        • Hsu C.-C.
        • Hwang S.-J.
        • Wen C.-P.
        • et al.
        High prevalence and low awareness of CKD in Taiwan: a study on the relationship between serum creatinine and awareness from a nationally representative survey.
        Am J Kidney Dis. 2006; 48: 727-738
        • McClellan W.M.
        • Newsome B.B.
        • McClure L.A.
        • et al.
        Chronic kidney disease is often unrecognized among patients with coronary heart disease: the REGARDS Cohort Study.
        Am J Nephrol. 2008; 29: 10-17
        • Flessner M.F.
        • Wyatt S.B.
        • Akylbekova E.L.
        • et al.
        Prevalence and awareness of CKD among African Americans: the Jackson Heart Study.
        Am J Kidney Dis. 2009; 53: 238-247
        • McIntyre N.J.
        • Fluck R.
        • McIntyre C.
        • Taal M.
        Treatment needs and diagnosis awareness in primary care patients with chronic kidney disease.
        Br J Gen Pract. 2012; 62 (e227-232)
        • Plantinga L.C.
        • Boulware L.E.
        • Coresh J.
        • et al.
        Patient awareness in chronic kidney disease: trends and predictors.
        Arch Intern Med. 2008; 168: 2268-2275
        • Plantinga L.C.
        • Tuot D.S.
        • Powe N.R.
        Awareness of chronic kidney disease among patients and providers.
        Adv Chronic Kidney Dis. 2010; 17: 225-236
        • Devraj R.
        • Borrego M.E.
        • Vilay A.M.
        • Pailden J.
        • Horowitz B.
        Awareness, self-management behaviors, health literacy and kidney function relationships in specialty practice.
        World J Nephrol. 2018; 7: 41-50
        • Whaley-Connell A.
        • Sowers J.R.
        • McCullough P.A.
        • et al.
        Diabetes mellitus and CKD awareness: the Kidney Early Evaluation Program (KEEP) and National Health and Nutrition Examination Survey (NHANES).
        Am J Kidney Dis. 2009; 53: S11-S21
        • Tuot D.S.
        • Plantinga L.C.
        • Hsu C.
        • Powe N.R.
        Is awareness of chronic kidney disease associated with evidence-based guideline-concordant outcomes?.
        Am J Nephrol. 2012; 35: 191-197
        • Plantinga L.
        • Grubbs V.
        • Sarkar U.
        • et al.
        Nonsteroidal anti-inflammatory drug use among persons with chronic kidney disease in the United States.
        Ann Fam Med. 2011; 9: 423-430
        • Tuot D.S.
        • Plantinga L.C.
        • Judd S.E.
        • et al.
        Healthy behaviors, risk factor control and awareness of chronic kidney disease.
        Am J Nephrol. 2013; 37: 135-143
        • Daker-White G.
        • Rogers A.
        • Kennedy A.
        • Blakeman T.
        • Blickem C.
        • Chew-Graham C.
        Non-disclosure of chronic kidney disease in primary care and the limits of instrumental rationality in chronic illness self-management.
        Soc Sci Med. 2015; 131: 31-39
        • Centers for Disease Control and Prevention (CDC), National Center for Health Statistics (NCHS)
        National Health and Nutrition Examination Survey Data.
        U.S. Department of Health and Human Services, Centers for Disease Control and Prevention, Hyattsville, MD1999
        https://wwwn.cdc.gov/nchs/nhanes/
        Date accessed: May 7, 2019
        • Levey A.S.
        • Stevens L.A.
        • Schmid C.H.
        • et al.
        A new equation to estimate glomerular filtration rate.
        Ann Intern Med. 2009; 150: 604-612
        • Tangri N.
        • Stevens L.A.
        • Griffith J.
        • et al.
        A predictive model for progression of chronic kidney disease to kidney failure.
        JAMA. 2011; 305: 1553-1559
        • Tangri N.
        • Grams M.E.
        • Levey A.S.
        • et al.
        Multinational assessment of accuracy of equations for predicting risk of kidney failure: a meta-analysis.
        JAMA. 2016; 315: 164-174
        • Peeters M.J.
        • van Zuilen A.D.
        • van den Brand J.A.J.G.
        • et al.
        Validation of the kidney failure risk equation in European CKD patients.
        Nephrol Dial Transplant. 2013; 28: 1773-1779
        • Hingwala J.
        • Wojciechowski P.
        • Hiebert B.
        • et al.
        Risk-based triage for nephrology referrals using the kidney failure risk equation.
        Can J Kidney Health Dis. 2017; 4: 1-9
        • Tangri N.
        • Ferguson T.
        • Komenda P.
        Pro: risk scores for chronic kidney disease progression are robust, powerful and ready for implementation.
        Nephrol Dial Transplant. 2017; 32: 748-751
        • Crim M.T.
        • Yoon S.S.
        • Ortiz E.
        • et al.
        National surveillance definitions for hypertension prevalence and control among adults.
        Circ Cardiovasc Qual Outcomes. 2012; 5: 343-351
        • International Expert Committee
        International Expert Committee report on the role of the A1C assay in the diagnosis of diabetes.
        Diabetes Care. 2009; 32: 1327-1334
        • Vittinghoff E.
        • Glidden D.V.
        • Shiboski S.C.
        • McCulloch C.E.
        Regression Methods in Biostatistics.
        Springer, New York, NY2005
        • Delanaye P.
        • Jager K.J.
        • Bökenkamp A.
        • et al.
        CKD: a call for an age-adapted definition.
        J Am Soc Nephrol. 2019; 30: 1785-1805
        • Wesson D.E.
        Does eGFR by any number mean the same?.
        J Am Soc Nephrol. 2019; 30: 1806-1807
        • Chertow G.M.
        • Beddhu S.
        Modification of eGFR-based CKD definitions: perfect, or enemy of the good?.
        J Am Soc Nephrol. 2019; 30: 1807-1809
        • Parker J.D.
        • Talih M.
        • Malec D.J.
        • et al.
        National Center for Health Statistics data presentation standards for proportions.
        Vital Health Stat 2. 2017; : 1-22
        • National Kidney Foundation
        Public awareness initiative for AAKH announced as a public-private partnership with NKF and ASN. November 4, 2019.
        • Greer R.C.
        • Cooper L.A.
        • Crews D.C.
        • Powe N.R.
        • Boulware L.E.
        Quality of patient-physician discussions about CKD in primary care: a cross-sectional study.
        Am J Kidney Dis. 2011; 57: 583-591
        • Greer R.C.
        • Crews D.C.
        • Boulware L.E.
        Challenges perceived by primary care providers to educating patients about chronic kidney disease.
        J Ren Care. 2012; 38: 174-181
        • Crinson I.
        • Gallagher H.
        • Thomas N.
        • de Lusignan S.
        How ready is general practice to improve quality in chronic kidney disease? A diagnostic analysis.
        Br J Gen Pract. 2010; 60: 403-409
        • Smekal M.D.
        • Tam-Tham H.
        • Finlay J.
        • et al.
        Perceived benefits and challenges of a risk-based approach to multidisciplinary chronic kidney disease care: a qualitative descriptive study.
        Can J Kidney Health Dis. 2018; 5https://doi.org/10.1177/2054358118763809
        • Smekal M.D.
        • Tam-Tham H.
        • Finlay J.
        • et al.
        Patient and provider experience and perspectives of a risk-based approach to multidisciplinary chronic kidney disease care: a mixed methods study.
        BMC Nephrol. 2019; 20: 110
        • Blakeman T.
        • Protheroe J.
        • Chew-Graham C.
        • Rogers A.
        • Kennedy A.
        Understanding the management of early-stage chronic kidney disease in primary care: a qualitative study.
        Br J Gen Pract. 2012; 62: e233-e242
        • Abdi Z.
        • Gallagher H.
        • O’Donoghue D.
        Telling the truth: why disclosure matters in chronic kidney disease.
        Br J Gen Pract. 2012; 62: 172-173
        • Tuot D.S.
        • Zhu Y.
        • Velasquez A.
        • et al.
        Variation in patients’ awareness of CKD according to how they are asked.
        Clin J Am Soc Nephrol. 2016; 11: 1566-1573
        • Tuot D.S.
        • Wong K.K.
        • Velasquez A.
        • et al.
        CKD awareness in the general population: performance of CKD-specific questions.
        Kidney Med. 2019; 1: 43-50
        • National Kidney Foundation
        K/DOQI clinical practice guidelines for chronic kidney disease: evaluation, classification, and stratification.
        Am J Kidney Dis. 2002; 39: S1-S266