Time-Dependent Association Between Metabolic Syndrome and Risk of CKD in Korean Men Without Hypertension or Diabetes
Received 1 February 2008; accepted 15 July 2008. published online 06 October 2008.
Background
The time-dependent association between metabolic syndrome and risk of chronic kidney disease (CKD) is not clear.
Study Design
Prospective cohort study.
Setting & Participants
The study cohort was composed of 10,685 healthy men without CKD, hypertension, or diabetes who participated in a health-checkup program at a large work site.
Predictor
Metabolic syndrome.
Outcomes & Measurements
CKD was defined as an estimated glomerular filtration rate (GFR) less than 60 mL/min/1.73 m2. A standard Cox proportional hazards model and a time-dependent Cox model were used to calculate adjusted hazard ratios (HRs) in the CKD model.
Results
During 40,616.8 person-years of follow-up, 291 incident cases of CKD developed; 787 patients (7.4%) had metabolic syndrome at baseline and 1,444 (14.4%) developed incident metabolic syndrome during follow-up. After adjustment for age, baseline GFR, γ-glutamyltransferase level, and uric acid level, metabolic syndrome at baseline was associated with a significantly increased risk of CKD (HR, 1.99; 95% confidence interval, 1.46 to 2.73). Metabolic syndrome over time as a time-dependent variable also predicted the development of CKD (HR, 1.75; 95% confidence interval, 1.28 to 2.39). The relationship between metabolic syndrome and incident CKD remained significant, even after further adjustment for the homeostasis model assessment of insulin resistance, high-sensitivity C-reactive protein level, current smoking, alcohol consumption, or regular exercise. In addition, there were graded relationships between number of metabolic syndrome traits or quintile of homeostasis model assessment of insulin resistance over time as a time-dependent variable and risk of CKD. Both increased triglyceride and low high-density lipoprotein cholesterol levels among metabolic syndrome traits were associated with significantly increased risk of CKD. These results were effectively unchanged, even after additional adjustment for incident hypertension and incident diabetes.
Limitations
Estimated GFR was used instead of a directly measured GFR to define CKD.
Conclusion
Metabolic syndrome is an independent risk factor for the development of CKD in Korean men without hypertension or diabetes, even with changes in status of metabolic syndrome over time.
ABSTRACT