Medium-grade proteinuria is a risk factor for incident markers of chronic kidney disease

Abstract

Objective: Medium-grade proteinuria (100–500 mg/g creatinine) is common among people living with HIV/AIDS (PLWHA) but is often undetected or ignored. This prospective, observational cohort study examined medium-grade proteinuria as a risk factor for markers of chronic kidney disease (CKD). Methods: Quantitative urine samples were collected from 241 PLWHA without known renal disease at baseline between January 2009 and February 2011 and at follow-up 240 weeks later. Multivariate analysis was performed to assess medium-grade proteinuria as a risk factor for incident markers of CKD (estimated glomerular filtration rate < 60 mL/min/1.73 m2, albuminuria, phosphaturia). Results: Incident markers of CKD were identified in 33 patients (14%), of whom 24 (74%) had medium-grade proteinuria at baseline. Of these, 22 even had proteinuria of < 200 mg/g creatinine. Multivariate analysis showed an adjusted relative risk (aRR) of 2.4 for patients with baseline medium-grade proteinuria to develop signs of CKD. Age was identified as an additional independent predictor. By testing for interaction, tenofovir disoproxil fumarate (TDF)-independent proteinuria was strongly associated with incident CKD markers (aRR = 12.1). Conclusion: Medium-grade proteinuria of 100–500 mg/g creatinine is both frequent in PLWHA and a significant risk factor for developing markers of CKD, especially in the absence of TDF. Relevant risk seems to be associated with proteinuria levels as low as 100–200 mg/g creatinine. Current guidelines recommend specific action for proteinuria exceeding 135–200 mg/g but still will miss a relevant number of PLWHA potentially at risk for CKD. An even lower cut-off to trigger nephrological work-up and potentially renoprotective interventions appears to be indicated.