Granulomatous interstitial nephritis on renal biopsy in HIV positive patients: prevalence and causes in Cape Town, South Africa.

INTRODUCTION: South Africa continues to be burdened by human immunodeficiency virus [HIV] and tuberculosis [TB]. In Cape Town, the epidemic of HIV-TB co-infection is as high as 70%. Granulomatous interstitial nephritis [GIN] has increased in frequency on renal biopsy. This study aimed to determine GIN prevalence and causes in HIV positive patients as well as renal outcomes, patient survival and associated factors.

METHOD: This observational cohort study reviewed HIV positive renal biopsies for GIN from 2005-2012. Causes of GIN (medications, TB, fungal and other), and baseline characteristics were analysed. A comparison of baseline data, renal function and survival was made between GIN and non-GIN cohorts.

RESULTS: There were 45/316 biopsies demonstrating GIN. TB was the likely cause of GIN in 27 [60%] and 9 [20%] were due to a drug. Low eGFR was statistically significant for mortality in both GIN [p=0.045] and non-GN cohorts [p<0.000]. In the GIN group there were 12 (26.7%) deaths. Mortality for all patients was greatest in the first 6 months [p= 0.057]. TB co-infection in both cohorts was associated with a higher mortality. The multivariate logistic regression demonstrated that a higher uPCR and lower eGFR were statistically associated with death.

CONCLUSION: GIN is common in HIV positive renal biopsies in Cape Town. TB-GIN was the commonest cause and associated with a high early mortality. GIN should be considered in HIV positive patients with acute kidney injury, its presence conveys a survival benefit. There is a need for improved diagnostic accuracy and treatment strategies of TB-GIN. This article is protected by copyright. All rights reserved.