Glomerular filtration rate estimated using creatinine, cystatin C or both markers and the risk of clinical events in HIV ‐infected individuals

Objectives The accuracy and precision of glomerular filtration rate ( GFR ) estimating equations based on plasma creatinine ( GFR cr ), cystatin C ( GFR cys ) and the combination of these markers ( GFR cr‐cys ) have recently been assessed in HIV ‐infected individuals. We assessed the associations of GFR , estimated by these three equations, with clinical events in HIV ‐infected individuals. Methods We compared the associations of baseline GFR cr , GFR cys and GFR cr‐cys [using the C hronic K idney D isease E pidemiology C ollaboration ( CKD‐EPI ) equations] with mortality, cardiovascular events ( CVEs ) and opportunistic diseases ( ODs ) in the S trategies for the M anagement of A ntiretroviral T herapy ( SMART ) study. We used C ox proportional hazards models to estimate unadjusted and adjusted hazard ratios per standard deviation ( SD ) change in GFR . Results A total of 4614 subjects from the SMART trial with available baseline creatinine and cystatin C data were included in this analysis. Of these, 99 died, 111 had a CVE and 121 had an OD . GFR cys was weakly to moderately correlated with HIV RNA , CD4 cell count, high‐sensitivity C ‐reactive protein, interleukin‐6, and D ‐dimer, while GFR cr had little or no correlation with these factors. GFR cys had the strongest associations with the three clinical outcomes, followed closely by GFR cr‐cys , with GFR cr having the weakest associations with clinical outcomes. In a model adjusting for demographics, cardiovascular risk factors, HIV ‐related factors and inflammation markers, a 1‐ SD lower GFR cys was associated with a 55% [95% confidence interval ( CI ) 27−90%] increased risk of mortality, a 21% (95% CI 0−47%) increased risk of CVE , and a 22% (95% CI 0−48%) increased risk of OD . Conclusions Of the three CKD‐EPI GFR equations, GFR cys had the strongest associations with mortality, CVE and OD .