Hepatitis C infection and risk of diabetes: A systematic review and meta-analysis

Background/Aims Several studies found hepatitis C (HCV) increases risk of Type II diabetes mellitus (DM). However, others found no or only sub-group specific excess risk. We performed meta-analyses to examine whether HCV infection does increase DM risk in comparison to the general population and in other sub-groups with increased liver disease rates including with hepatitis B (HBV). Methods We followed standard guidelines for performance of meta-analyses. Two independent investigators identified eligible studies through structured keyword searches in relevant databases including PubMed. Results We identified 34 eligible studies. Pooled estimators indicated significant DM risk in HCV-infected cases in comparison to non-infected controls in both retrospective (ORadjusted = 1.68, 95% CI 1.15–2.20) and prospective studies (HRadjusted = 1.67, 95% CI 1.28–2.06). Excess risk was also observed in comparison to HBV-infected controls (ORadjusted = 1.80, 95% CI 1.20–1.40) with suggestive excess observed in HCV+/HIV+ cases in comparison to HIV+ controls (ORunadjusted = 1.82, 95% CI 1.27–2.38). Conclusions Our finding of excess DM risk with HCV infection in comparison to non-infected controls is strengthened by consistency of results from both prospective and retrospective studies. The excess risk observed in comparison to HBV-infected controls suggests a potential direct viral role in promoting DM risk, but this needs to be further examined.