Subclinical Tubular Injury in HIV-Infected Individuals on Antiretroviral Therapy: A Cross-sectional Analysis

Serum phosphate levels and hypoposphatemia in the study groups. (A) There were no significant differences among groups in serum phosphate values. Values given as mean (point), median (solid line), 25th and 75th percentiles (box), range (crosses), and 5th and 95th percentiles (error bars). The dashed line represents the lower limit of the normal adult range (< 2.48 mg/dL). (B) The proportion of patients in the group exposed to tenofovir (TDF group) who had a serum phosphate value less than the normal range was greater than in the antiretroviral treatment (ART)-naive group and those with no exposure to tenofovir (non-TDF group), but this difference was not statistically significant. Conversion factor for serum phosphate in mg/dL to mmol/L, ×0.3229.

Urinary markers. (A) Urinary retinol-binding protein (RBP)-creatinine (creat) ratio (normal range, < 159 μg/g]) was higher in the group exposed to tenofovir (TDF group) than either the antiretroviral treatment (ART)-naive group or those with no exposure to tenofovir (non-TDF group). (B) Urinary N-acetyl-β-d-glucosaminidase (NAG)-creat ratio (normal range, < 248 μmol/h/g) was higher in both the TDF and non-TDF treatment groups compared with the ART-naive group. (C) Urinary albumin-creat ratio (normal range, < 22 mg/g) did not differ significantly among the study groups. (D) Urinary protein-creat ratio (normal range, < 115 mg/g) was greater in the TDF group than either the ART-naive or non-TDF group. Values given are mean (point), median (solid line), 25th and 75th percentiles (box), range (crosses), and 5th and 95th percentiles (error bars). Dashed lines represent the upper limits of the normal range. Conversion factor for a urinary value expressed per gram of creatinine to a value per millimoles of creatinine, ×0.113.

The relationship between urinary albumin-creatinine (creat) ratio and other urinary markers. Scatter plots for all 3 study groups (antiretroviral treatment [ART]-naive [x], group exposed to tenofovir [TDF; filled circle], and group not exposed to tenofovir [non-TDF; open square]) show the relationship between urinary albumin-creat and (A) urinary retinol-binding protein (RBP)-creat ratios (rs = 0.53; P = 0.01); (B) urinary N-acetyl-β-d-glucosaminidase (NAG)-creat ratio (rs = 0.56; P = 0.01); and (C) urinary protein-creat ratio (rs = 0.20; P = 0.05).

Sensitivity of either urinary albumin-creatinine ratio or protein-creatinine ratio in detecting renal tubular dysfunction. The proportion of patients with an increase (greater than the normal adult range) in either urinary albumin-creatinine (hatched bar) or protein-creatinine (gray bar) ratio was considerably lower than the proportion with abnormal tubular proteinuria (defined as increased urinary retinol-binding protein [RBP]-creatinine and/or N-acetyl-β-d-glucosaminidase [NAG]-creatinine ratio) (black bar) in all 3 study groups. Abbreviations: ARTN, antiretroviral therapy naive; non-TDN, group without exposure to tenofovir; TDN, group exposed to tenofovir.