Urinary liver-type fatty acid-binding protein levels as a potential risk factor for renal dysfunction in male HIV-infected Japanese patients receiving antiretroviral therapy: a pilot study

Renal dysfunction is recognized with increasing frequency among the non-infectious co-morbidities associated with human immunodeficiency virus (HIV) infection. Recently, urinary liver-type fatty acid-binding protein (L-FABP) was suggested to be a predictor of the progression of renal dysfunction in patients without HIV. However, little is known regarding the utility of urinary L-FABP as a predictor of renal dysfunction in patients with HIV. A retrospective, observational, single-centre study was conducted between July 2014 and December 2016. The primary outcome was renal dysfunction defined as decrease in estimated glomerular filtration rate to less than 60 ml/min/1.73 m(2). To estimate the effect of urinary L-FABP, proteinuria category, and urinary beta 2 microglobulin (beta 2MG) on the time to the first event, a log-rank test was performed. Accuracy, determined by area under the curve and calculated from receiver operating characteristic curves, was also assessed. Thirty Japanese outpatients with HIV receiving antiretroviral therapy (ART) were enrolled. The primary outcome occurred in five patients during the follow-up period. Urinary L-FABP level and proteinuria category were significantly associated with renal dysfunction (p = 0.045 and p = 0.037, respectively). In contrast, urinary beta 2MG level was not significantly associated with renal dysfunction (p = 0.141). Urinary L-FABP was the most accurate predictor of renal dysfunction among the three urinary parameters. In conclusion, urinary L-FABP levels in HIV patients receiving ART were more accurate for predicting renal dysfunction than proteinuria and urinary beta 2MG. In addition, urinary L-FABP helped to discriminate those patients with a higher risk for renal dysfunction.