OBJECTIVETo investigate the effects of adefovir dipivoxil (ADV) on blood phosphorus metabolism in patients with chronic hepatitis B (CHB).

METHODSPatients with hepatitis B surface antigen (HBsAg)-positive CHB were treated with ADV alone, ADV combined with interferon (IFN), or ADV combined with lamivudine (LAM). Changes in levels of calcium, phosphate, urea, and creatinine were assessed at treatment weeks 4, 12, 24, 48, 72 and 96. Statistical analysis was carried out with SPSS 16 software; influential factors were analyzed by ANOVA and non-conditional logistic regression analysis.

RESULTSDuring the course of treatments, 32 (42.6%) of the patients presented with low phosphorus. The highest incidence of low phosphorus was found to have occurred at treatment week 24 (25.0%, 27.5% and 36.4% respectively, with no statistical difference between three groups, x2=0.225, P>0.225). Patients with hypophosphatemia did not show a significant difference in serum phosphorus levels from the other patients (F=1.853, P=0.169). Logistic regression showed a correlation between low phosphorus and sex (x2=7.876, P<0.05), age (t=2.479, P<0.05), and serum creatinine (t =-2.256, P<0.05), but not with blood urea nitrogen or blood calcium (P>0.05).

CONCLUSIONADV antiviral treatment can decrease the blood phosphorous levels of CHB patients, particularly over extended time of treatment, and the occurrence of low phosphorus is more common than of mild phosphorus decrease.Male and elderly patients may be at greater risk of this complication. The incidence and severity of low phosphorus is not significantly different for the different ADV-based treatment regimens.