Monitoring of early renal injury in chronic hepatitis B patients with long-term adefovir dipivoxil treatment

Abstract

Objective To evaluate urinary β2-microglobulin (β2-MG) and retinoid binging protein (RBP) in monitoring of early renal impairment in chronic hepatitis B (CHB) patients with long-term adefovir dipivoxil (ADV) treatment. Methods Three hundred and fifty five patients with CHB admitted in Shaoxing Municipal Hospital from June 2009 to June 2011 were enrolled in the study, among whom 180 cases (study group) were treated with ADV monotherapy (n=100) or ADV + lamivudine (LAM) combination therapy (n=80); and 175 cases (control group) were treated with entecavir (ETV). Serum creatinine, urinary β2-MG, RBP and creatinine were measured and glomerular filtration rate (eGFR) was estimated regularly during 5-year follow up. Kaplan-Meier method was used to calculate the cumulative incidence of changes in urinary β2-MG and RBP. Results Five-year follow-up results showed that in study group 2, 6, 10, 14 and 24 cases developed urinary β2-MG abnormality in year 1, 2, 3, 4 and 5 of treatment, respectively; and 2, 7, 11, 16 and 20 cases developed urinary RBP abnormality in year 1, 2, 3, 4 and 5 of treatment, respectively; eGFR decreased 20%-30% from baseline in 20 cases, 30%-50% in 13 cases and >50% in 2 cases. The decrease of eGFR ≥30% in 5 years was significantly correlated with urinary RBP and β2-GM abnormality. However, both serum creatinine and eGFR remained stable during the 5 years of follow-up in control group; only 2 cases developed urinary β2-MG abnormality and 3 cases developed urinary RBP abnormality. Conclusions Urinary RBP and β2-MG are sensitive biomarkers of early renal injury during long-term ADV treatment in CHB patients, and ADV should not be used as first-line treatment for CHB. Key words: Hepatitis B, chronic; Renal impairment; Adefovir dipivoxil; Entecavir; Urine β2-microglobulin; Retinol binding protein