This study investigated the kinetics of estimated glomerular filtration rate (eGFR) and quantitative hepatitis B surface antigen (qHBsAg) in telbivudine (LdT)-treated chronic hepatitis B (CHB) patients whose treatment was subsequently adjusted with the adding on adefovir or by switching to tenofovir disoproxil fumarate (TDF) as rescue. Of 295 CHB patients initially treated with LdT, 102 of them who subsequently receiving either adding-on adefovir (group A, n = 58) or switching to TDF (group B, n = 44) for more than 24 months were enrolled. Serial eGFR and qHBsAg levels (3 to 6 monthly) in both LdT monotherapy and rescue therapy periods were analyzed retrospectively. Subsequent decline of qHBsAg especially in rescue therapy period were noted (p<0.001 and p = 0.068 in group A and B). However, patients in group B achieved a significant increase of eGFR (p = 0.010) in LdT monotherapy period but had a significant decline of eGFR (p<0.001) in rescue therapy period. In contrast, patients in group A maintained eGFR levels in both periods. Meanwhile, switch to TDF (hazard ratio: 3.036; 95% confidence interval: 1.040-8.861; p = 0.042) was the sole factor related to the decrease of eGFR>20% from baseline. Both rescue therapies achieved subsequent declines of qHBsAg over time but caused different changes in eGFR. LdT-based rescue therapy maintained eGFR but TDF switching therapy descended eGFR. Therefore, it is essential to monitor patient's renal function intensively when switching from LdT to TDF as a rescue strategy.
