Supplementary Material for: Associations of Urine Biomarkers with Kidney Function Decline in HIV-Infected and Uninfected Men

Background: HIV-infected (HIV+) persons are at increased risk of chronic kidney disease, but serum creatinine does not detect early losses in kidney function. We hypothesized that urine biomarkers of kidney damage would be associated with subsequent changes in kidney function in a contemporary cohort of HIV+ and HIV-uninfected (HIV–) men. Methods: In the Multicenter AIDS Cohort Study, we measured baseline urine concentrations of 5 biomarkers from 2009 to 2011 in 860 HIV+ and 337 HIV– men: albumin, alpha-1-microglobulin (α1m), interleukin-18 (IL-18), kidney injury molecule-1 (KIM-1), and procollagen type III N-terminal propeptide (PIIINP). We evaluated associations of urine biomarker concentrations with annual changes in estimated glomerular filtration rate (eGFR) using multivariable linear mixed models adjusted for demographics, traditional kidney disease risk factors, HIV-related risk factors, and baseline eGFR. Results: Over a median follow-up of 4.8 years, the average annual eGFR decline was 1.42 mL/min/1.73 m²/year in HIV+ men and 1.22 mL/min/1.73 m²/year in HIV– men. Among HIV+ men, the highest vs. lowest tertiles of albumin (–1.78 mL/min/1.73 m²/year, 95% CI –3.47 to –0.09) and α1m (–2.43 mL/min/1.73 m²/year, 95% CI –4.14 to –0.73) were each associated with faster annual eGFR declines after multivariable adjustment. Among HIV– men, the highest vs. lowest tertile of α1m (–2.49 mL/min/1.73 m²/year, 95% CI –4.48 to –0.50) was independently associated with faster annual eGFR decline. Urine IL-18, KIM-1, and PIIINP showed no independent associations with eGFR decline, regardless of HIV serostatus. Conclusions: Among HIV+ men, higher urine albumin and α1m are associated with subsequent declines in kidney function, independent of eGFR.