Matched population-based study examining the risk of type 2 diabetes in people with and without diagnosed hepatitis C virus infection

Meta-analyses have found hepatitis C virus (HCV) infection to be associated with an increased risk of type 2 diabetes mellitus (T2DM). Here, we examine this association within a large population-based study, according to RNA status.
A data-linkage approach was used to examine the excess risk of diagnosed T2DM in people diagnosed with HCV-antibodies in Scotland (21,929 Ab+ves; involving 15,827 RNA+ves, 3927 RNA−ves and 2175 with unknown RNA-status) compared to that of a three-fold larger general population sample matched for sex, age and postcode (65,074 Ab−ves). To investigate effects of ascertainment bias the following periods were studied: up to one year before (pre-HCV)/within one year of (peri-HCV)/more than one year post (post-HCV) the date of HCV-diagnosis.
T2DM had been diagnosed in 2.9% of Ab+ves (including 3.2% of RNA+ves and 2.3% of RNA-ves) and 2.7% of Ab−ves. A higher proportion of T2DM was diagnosed in the peri-HCV period (i.e. around the time of HCV-diagnosis) for the Ab+ves (22%) compared to Ab−ves (10%). In both the pre-HCV and post-HCV periods, only those Ab+ves living in less deprived areas (13% of the cohort) were found to have a significant excess risk of T2DM compared to Ab−ves (adjusted odds ratio in the pre-HCV period: 4.0 for females and 2.3 for males; adjusted hazard ratio in the post-HCV period: 1.5). These findings were similarly observed for both RNA+ves (chronic) and RNA−ves (resolved).
In the largest study of T2DM among chronic HCV-infected individuals to date, there was no evidence to indicate that infection conveyed an appreciable excess risk of T2DM at the population level.