Subclinical proximal tubulopathy in hepatitis B: The roles of nucleot(s)ide analogue treatment and the hepatitis B virus

A prospective cohort study of renal function and bone turnover in adults with hepatitis B virus (HBV)-HIV co-infection with high prevalence of tenofovir-based antiretroviral therapy use

OBJECTIVE

Tenofovir disoproxil fumarate (TDF) is a common component of antiretroviral therapy in hepatitis B virus (HBV)-HIV co-infected adults but few studies have evaluated worsening renal function and bone turnover, known effects of TDF.

METHODS

Adults from eight North American sites were enrolled in this cohort study. Research assessments were conducted at entry and every 24 weeks for ≤192 weeks. Bone markers were tested at baseline, week 96 and week 192 from stored serum. We evaluated changes in markers of renal function and bone turnover over time and potential contributing factors.

RESULTS

A total of 115 patients were prospectively followed; median age 49 years, 91% male and 52% non-Hispanic Black. Duration of HIV was 20.5 years. TDF use ranged from 80% to 92% throughout follow-up. Estimated glomerular filtration rate (eGFR) (ml/min/1.73m² ) decreased from 87.1 to 79.9 over 192 weeks (p < 0.001); however, the prevalence of eGFR <60 ml/min/1.73m² did not appear to differ over time (always <16%; p = 0.43). From baseline to week 192, procollagen type I N-terminal propeptide (P1NP) (146.7 to 130.5 ng/ml; p = 0.001), osteocalcin (14.4 to 10.2 ng/ml; p < 0.001) and C-terminal telopeptides of type I collagen (CTX-1) (373 to 273 pg/ml; p < 0.001) decreased. Younger age, male sex and overweight/obesity versus normal weight predicted a decrease in eGRF. Black race, healthy weight versus underweight, advanced fibrosis, undetectable HBV DNA, and lower parathyroid hormone level predicted worsening bone turnover.

CONCLUSION

In this HBV-HIV cohort with high prevalence of TDF use, several biomarkers of renal function and bone turnover indicated worsening status over approximately 4 years, highlighting the importance of clinical awareness in co-infected adults.

Safety of current antiviral drugs for chronic hepatitis B

INTRODUCTION

Oral nucleos(t)ide analogues (NUCs) are recommended as first-line therapy for chronic hepatitis B due to higher HBV-DNA suppression rates and safety profile. Long-term treatment with NUCs is often necessary to achieve durable viral suppression.

AREAS COVERED

This review provides an overview of the long-term safety data that have become available since entecavir (ETV) and tenofovir disoproxil fumarate (TDF) were first approved, and recent data on tenofovir alafenamide (TAF) in patients with CHB.

EXPERT OPINION

NUCs generally show remarkable safety in patients taking them for long periods. Nevertheless, renal and bone toxicity may occur in a minority of patients on TDF therapy. These effects have been overcome by the recent release of TAF. Moreover, the currently available data do not allow firm conclusions on superiority of TDF on ETV about HCC risk reduction. Observational studies involving more homogeneous cohorts are therefore needed; furthermore long-term studies assessing impact of TAF on this important topic are warranted.