Renal function of MDR-TB patients treated with kanamycin regimens or concomitantly with antiretroviral agents

SETTING: To compare renal insufficiency among multidrug-resistant tuberculosis (MDR-TB) patients treated with kanamycin (KM) based regimens and those treated concomitantly with tenofovir disoproxil fumarate (TDF) or other antiretroviral therapy (ART) regimens in Namibia. DESIGN: Retrospective review of the treatment records and laboratory tests of patients initiated on MDR-TB treatment (January-December 2014). The glomerular filtration rates (eGFR) estimated pre- and post-treatment were compared using the analysis of variance test. Renal insufficiency was defined as an eGFR of <60 ml/min/1.73 m2. Use of KM or TDF and association with renal insufficiency was assessed using Kaplan-Meier plots and Cox proportional hazards analysis. RESULTS: The baseline mean eGFR for the three groups was similar (P = 0.24): 139.3 ± 25.6 ml/min for the KM group (n = 68), 131.1 ± 25.7 ml/min for the KM+TDF group (n = 44) and 134.2±34.4 ml/min for the KM+Other group (n = 23). After 8 months, the values had declined significantly to respectively 104.8 ± 37.5 ml/min (P < 0.001), 101.5 ± 38.3 ml/min (P < 0.001) and 111.5 ± 41.7 ml/min (P = 0.01). Co-treatment with KM+ART was associated with an increased risk of renal insufficiency (hazard ratio [HR] 1.8, 95%CI 0.7-4.1, P = 0.20 for KM+TDF, and HR 3.5, 95%CI 1.4-8.2, P = 0.005 for KM+Other ART). CONCLUSION: Renal function declined at a similar rate in MDR-TB patients treated with KM-based regimens compared with patients treated concomitantly with TDF-based or other ART. The risk of renal insufficiency was greater for patients on ART.