Background: Hepatitis C has been associated with an increased incidence of diabetes mellitus (DM) following renal transplantation (RT).
Methods: Patients who underwent RT between 1985 and 2001 were excluded if they showed DM prior to RT, graft survival of less than 90 days, and unknown anti-HCV status (n=15). Two groups (G1 and G2) were distinguished according to the immunosuppressive regimen: G1 (transplanted 1985-1996) received steroids, azathioprine, and cyclosporine (n=330), whereas G2 (1997-2000) received new drugs in several combinations (MMF in 87% and/or tacrolimus in 35% [n=240]). Patients with HCV antibodies pre- and/or post-RT were considered HCV-positive. Post-RT DM requiring prolonged treatment with oral antidiabetics or insulin (>1 month) was assessed using Kaplan-Meier curves and Cox analysis.
Results: G2 patients were significantly older, had a greater body mass index (BMI), and suffered significantly less from acute rejection episodes during the first year than G1 patients. Furthermore, fewer required maintenance steroids. HCV-positivity was more common in G1 than in G2 (n=96, 29.1% vs n=27, 11.3%). Six G2 patients were successfully treated with interferon pre-RT, achieving negative PCR-HCV status (maintained post-RT). DM incidence at 4 years was similar in G1 and G2 (8.8% and 8.2%). G1 HCV-positive patients showed a greater risk of developing DM than HCV-negative patients (28.0% vs 6.2% at 10 years; P=001). In G1, multivariate analysis showed that age, BMI, and HCV-positivity were significant risk factors predicting DM (relative risk, 5.7; 95% confidence interval 2.7-12). In G2 patients, HCV was not associated with an increased risk of DM; in the multivariate analysis only age appeared to be a risk factor.
Conclusions: The reported relationship between hepatitis C and post-RT DM was not observed among patients receiving new immunosuppressive treatments. Confirmation of this finding requires extended follow up. The reduced use of steroids and effective pre-RT use of interferon may also be responsible for the benefit.