Simultaneous measurement of urinary albumin and total protein may facilitate decision‐making in HIV‐infected patients with proteinuria

Abstract

ObjectiveWe recently showed that a urine albumin/total protein ratio (uAPR) < 0.4 identifies tubular pathology in proteinuric patients. In tubular disorders, proteinuria is usually of low molecular weight and contains relatively little albumin. We tested the hypothesis that uAPR is useful in identifying tubular pathology related to antiretroviral use in HIV-infected patients. MethodsWe retrospectively identified urine protein/creatinine ratios (uPCRs) in HIV-infected patients. A subset of samples had uPCR and urine albumin/creatinie ratio (uACR) measured simultaneously. We classified proteinuric patients (uPCR > 30 mg/mmol) into two groups: those with predominantly 'tubular' proteinuria (TP) (uAPR < 0.4) and those with predominantly 'glomerular' proteinuria (GP) (uAPR Ն 0.4). ResultsA total of 618 of 5244 samples from 1378 patients had uPCR Ն 30 mg/mmol. uAPRs were available in 144 patients: 46 patients (32%) had TP and 21 (15%) GP; the remainder had uPCR < 30 mg/mmol. The TP group had a higher fractional excretion of phosphate compared with the GP group (mean 27% vs. 16%, respectively; P < 0.01). Patients with TP were more likely to be on tenofovir and/or a boosted protease inhibitor compared with those with GP. In 18 patients with heavy proteinuria (uPCR > 100 mg/mmol), a renal assessment was made; eight had a kidney biopsy. In all cases, the uAPR results correlated with the nephrological diagnosis. ConclusionsIn HIV-infected patients, measuring uAPR may help to identify patients in whom a renal biopsy is indicated, and those in whom tubular dysfunction might be an important cause of proteinuria and which may be related to antiretroviral toxicity. We suggest that this would be useful as a routine screening procedure in patients with proteinuria.

Absence of Decline of Kidney Function in Human Immunodeficiency Virus-Infected Patients Under Routine Clinical Management

“…We observed that the prevalence of glomerular and tubular proteinuria in our sample was close, 7.9 and 10.8%, respectively. This frequency of glomerular proteinuria is in accordance with other published data [4,5,12,31,32]. Studies that have attempted to evaluate glomerular and tubular proteinuria simultaneously during HIV infection are however scarce in the literature.…”

Tubular and glomerular proteinuria in HIV-infected adults with estimated glomerular filtration rate ≥60 ml/min per 1.73 m2

“…Indeed, early stages of CKD are defined by kidney damage, assessed through abnormal presence of urinary markers (protein, albumin), without alteration of the GFR. The early screening of glomerular or tubular proteinuria in HIV-infected patients using a simple method [16] can help identify factors associated with subclinical renal injury, hence to implement preventive or corrective measures. However, studies evaluating the prevalence and the determinants of proteinuria in HIV-infected patients are limited.…”

The Problem of Renal Function Monitoring in Patients Treated With the Novel Antiretroviral Drugs

“…[19][20][21][22] indicates glomerular proteinuria, while a ratio lower than 0.4 is a marker of tubular proteinuria. 27 Tubular proteinuria can also be detected by specific markers such as urinary excretion of retinol binding protein, α-1-microglobulin, β-2-microblobulin, and NGAL (neutrophil gelatinaseassociated lipocalin). 28 These are sensitive markers of tubular damage, yet are not readily available in all clinical labs.…”