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

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.

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.

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).

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.