Comparison of the effectiveness and renal safety of tenofovir versus entecavir in patients with chronic hepatitis B

Objective: To compare the effectiveness and renal safety of treatment with tenofovir versus entecavir in patients with chronic hepatitis-B. Methods: Retrospective study in hepatitis-B patients who initiated treatment with tenofovir or entecavir since January 1998 until 2013. The primary effectiveness variable was defined as viral DNA < 20 UI/ml (HBV-DNA) and the variable for renal safety was variations in glomerular filtration rate (eGFR) after 48 weeks of treatment. Results: The analysis was conducted in 64 patients (1:1), with similar characteristics except for the prevalence of naive patients (p=0.036), comorbidities (p=0.077) and nephrotoxic drugs (p=0.088) in the entecavi arm, while the tenofovir arm presented a prevalence of patients with HBV-DNA < 20 UI/ml (p=0.032) and HBeAg-positive (p=0.050). Statistical univariate analysis and adjustment for confounding variables was conducted through the Propensity Score (PS). The outcomes for the primary effectiveness variable showed tenofovir superiority after PS adjustment, with an OR adj =6.7 (95% CI:1.2-35.3; p=0.028). Three patients on tenofovir experienced seroconversion (p=0.148). The outcomes for the primary safety variable (eGFR < 60 ml/min/1.73m) showed no difference between both arms after adjustment, achieving an OR adj =0.6 (95% CI:0.1-2.8; p=0.521). The tenofovir arm registered two cases of treatment interruption due to renal toxicity, with subsequent recovery, including one Fanconi Syndrome. Comparación entre la efectividad y la seguridad renal del tenofovir y el entecavir en pacientes con hepatitis B crónica Resumen Objetivo: Comparar la efectividad y seguridad renal del tratamiento con tenofovir frente al entecavir en pacientes con hepatitis B crónica. Métodos: Estudio retrospectivo en pacientes con hepatitis B que iniciaron tratamiento con tenofovir o entecavir entre enero 1998-2013. La variable principal de la efectividad fue definida como DNA viral < 20 UI/ml (HBV-DNA) y la de la seguridad renal como variaciones en el filtrado glomerular (eGFR) tras 48 semanas de tratamiento. Resultados: Se analizaron un total de 64 pacientes (1:1), con características semejantes excepto por el predominio de pacientes sin tratamiento previo (p=0,036), comorbilidades (p=0,077) y fármacos nefrotóxicos (p=0,088) en el grupo-entecavir, y de pacientes con HBV-DNA < 20 UI/ml (p=0,032) y HBeAg-positivo (p=0,050) en el grupo-tenofovir. Se realizaron análisis estadísticos univariantes y se ajustaron las variables confusoras mediante Propensity score (PS). Los resultados para la variable principal de efectividad (HBV-DNA < 20 UI/ml) denotan una superioridad del tenofovir tras el ajuste por PS con una OR adj = 6,7 (IC95%: 1,2-35,3; p=0,028). Tres pacientes con tenofovir sufrieron seroconversión (p=0,148). Los resultados para la variable principal de seguridad (eGFR < 60ml/min/1.73m) no mostraron diferencias entre ambas ramas tras el ajuste, obteniendo una OR adj = 0,6 (IC95%: 0,1-2,8; p=0,521). El grupo-tenofovir registró dos casos de suspensión por toxicidad renal, con posterior recuperación, entre ellos un síndrome de Fanconi. * Autor para correspondencia. Correo electrónico: [email protected] (Beatriz López Centeno). Recibido el 26 de febrero de 2016; aceptado el 16 de mayo de 2016. DOI: 10.7399/fh.2016.40.4.10492 Los artículos publicados en esta revista se distribuyen con la licencia: Articles published in this journal are licensed with a: Creative Commons Attribution 4.0. https://creativecommons.org/licenses/by-nc-nd/4.0/ La revista Farmacia Hospitalaria no cobra tasas por el envío de trabajos, ni tampoco cuotas por la publicación de sus artículos. 280 Farm Hosp. 2016;40(4):279-286 Beatriz López Centeno et al. Contribution to scientific literature This study provides a direct comparison between two drugs in patients with chronic Hepatitis B (CHB) under actual clinical practice, a comparison that has been made in several studies against other analogues used in the CHB treatment but with limited data in as for the comparison between these two agents; and it also provides a direct comparison between the renal safety of entecavir and tenofovir and analysis of additional risk factors for developing kidney disease in CHB patients. The results of the study confirm the effectiveness and safety in clinical practice of both drugs and help improve the selection and individualization of treatment based on patient baseline characteristics; the role of hospital pharmacists is key to controlling and monitoring both the effectiveness and safety of pharmacological treatment of chronic ambulatory dispensation mainly due to its high impact on hospital costs and quality of care.