Clinical profile and outcome of patients with biopsy-proven acute interstitial nephritis in Cape Town: a 10-year review

Background: Acute interstitial nephritis (AIN) is a common cause of acute kidney injury that has not been adequately characterized in Sub-Saharan Africa (SSA) despite an increasing use of potentially inciting agents for the treatment of human immunodeficiency virus (HIV) and tuberculosis in the region. Methods: A retrospective audit of records of patients with biopsy-proven AIN diagnosed at Groote Schuur Hospital, Cape Town from the 1(st) of January, 2006, to the 31(st) of December, 2015. Results: 54 patients with biopsy-proven AIN were reviewed. The majority were of black African origin (59.2%), with HIV (42.8%) and HIV-tuberculosis coinfection (30.5%) as the most common comorbidities. Drug-related AIN was seen in 38 (67.9%) patients, with rifampicin as the most often implicated medication. Probable drugrelated AIN was seen in 3 (5.4%) patients, infection-related AIN in 8 (14.3%), and unspecified causes in 4 (7.4%). AIN was suspected in 44.6% of patients before biopsy. 18 patients (34%) received hemodialysis, while 19 (35.2%) were treated with corticosteroids. Complete renal recovery at 30 and 90 days was seen in 23 (42.6%) patients and 24 (45.3%) patients, respectively, with the majority seen among those with drug-induced AIN. Six (11.1%) patients died; 4 (10.5%) of the patients were in the drug-related group. There was no correlation between degree of interstitial inflammation and severity of renal failure (p = 0.10). On multivariate logistic regression, drug-related causes of AIN were predictive of complete recovery at day 30 (OR 16.63; 95% CI: 1.71 -161.6, p = 0.02), and presence of interstitial fibrosis reduced likelihood of recovery (OR 0.03; 95% CI 0.002 -0.46, p = 0.012). Steroid use did not influence partial recovery (OR 0.59, 95% CI 0.17 -1.77; p = 0.32) or complete recovery (OR 3.38, 95% CI 0.38 -30.39, p = 0.28). Conclusions: AIN is common in patients with HIV or those on treatment for tuberculosis. Drug-related AIN is often associated with improved outcomes. This is particularly reassuring in the SSA region where the use of potentially-inciting medications is rife from a high burden of HIV and tuberculosis.