Renal function outcomes in patients receiving TDF-containing antiretroviral therapy: a retrospective pilot study in Namibia

Introduction and aims: Combination antiretroviral therapy (cART) has improved morbidity and mortality in patients with HIV across countries including countries in sub-Sahara Africa. However, cART is associated with renal impairment. The lack of pre-cART data in a recently published study limited the discussion on renal-based treatment outcomes with cART, which could have important clinical implications. Consequently, the aim of this paper is to correct this. Methods: Longitudinal retrospective study, with renal function assessed pre-cART and at various time points on cART using the Cockcroft-Gault method. The data source was the patients’ care booklets. Results: 71 patients were included. The majority were adults and female. Before cART initiation, 70.4% and 29.6% had abnormal and normal CrCl, respectively. CrCl was normalised in 24% of patients, while abnormal in the remainder. The mean (median) time to normalisation was 47.4(33.7) months, observed more in paediatric than adult patients (p =0.014). However, in paediatric patients, normalisation took longer than in adult patients. The reduction in CrCl, was observed at variable time points. 9/16 patients experienced a decline during first-line cART and 7 of these were receiving TDF. 7/16 experienced this during second-line cART and 6 were receiving TDF. Conclusion: HIV is typically the cause of renal impairment prior to cART, with TDF likely to be the cause of renal impairment during cART. Consequently, co-administration of TDF with other nephrotoxic drugs should be undertaken with caution if unavoidable. Overall, improvement in renal impairment was faster in adults.