Hypophosphatemia in patients with hepatitis B virus infection undergoing long-term adefovir dipivoxil therapy

The purpose of this study was to clarify the frequency of hypophosphatemia and other clinical features in patients with hepatitis B undergoing long-term therapy with adefovir dipivoxil (ADF).

Seventeen hepatitis B patients treated with a combination of lamivudine and ADF were analyzed. They were divided into two groups: patients who developed hypophosphatemia (P < 2.5 mg/dL) (group A) and those who did not (group B). The frequency of hypophosphatemia and other clinical features were retrospectively analyzed.

There were six patients (35.3%) in group A. The treatment period was 57.3 ± 15.6 and 61.8 ± 25.7 months in groups A and B, respectively. No differences were found between the groups prior to treatment. Among the six patients in group A, osteomalacia was observed in two, while a pathological fracture of the scapula was found in one. Decreases in phosphate (96 weeks after starting ADF), estimated glomerular filtration rate (eGFR) (48 weeks) and uric acid (24 weeks) levels, and increases in creatinine and alkaline phosphatase were noted in group A.

Hypophosphatemia occurred in 35% of the patients under the long-term treatment with ADF. Although it was not possible to predict the decrease in phosphate before ADF therapy, decreases in uric acid and eGFR may be the early events relating to low phosphatemia.