Is urinary β2-microglobulin a reliable marker for assessment of renal tubular dysfunction in chronic hepatitis B patients receiving tenofovir therapy?

BACKGROUND AND AIM: Urinary β2-microglobulin (β2-M) is a marker for renal tubular dysfunction. The current study aimed to assess urinary β2-M as a reliable marker for early prediction of tenofovir disoproxil fumarate (TDF)-related nephrotoxicity among hepatitis B virus (HBV) patients.

METHODS

Forty-two HBV patients who were a candidate for TDF therapy or have recently started it (for less than 6 months) were enrolled and subjected to demographic, clinical, laboratory assessment, abdominal ultrasound and transient elastography. The glomerular filtration rate (GFR) was estimated using the Cockcroft-Gault equation. Also, urinary β2-M was measured by the ELISA method within 6 months after the introduction of TDF treatment and 6 months later.

RESULTS

Mean age was 41.8 (9.55) years, 27 were males and 59.5% of patients have elevated urinary β2-M after 6 months follow-up of TDF therapy. Urinary β2-M was 0.07 ± 0.07 μg/ml at baseline and insignificantly increased up to 0.09 ± 0.08 μg/ml after 6 months follow-up. Despite the insignificant increase in serum creatinine from 0.85 ± 0.23 mg/dl at baseline to 0.9 ± 0.21 mg/dl after 6 months and the insignificant decrease in eGFR from 126.2 ± 39.72 ml/min at baseline and 117.64 ± 42.23 ml/min at 6 months follow-up. No correlation was found between the changes in urinary β2-M and the changes in other renal function indices at baseline and 6 months follow-up.

CONCLUSIONS

Short-term TDF therapy is associated with nonsignificant changes either in eGFR or urinary β2-M; these changes are not clinically relevant that indicates disease progression. Therefore, the suitability of urinary β2-M as a screening tool for tenofovir induced tubular dysfunction should be further.