Sustained virological response does not improve long-term glycaemic control in patients with type 2 diabetes and chronic hepatitis C.

Background: Sustained virological response to treatment for chronic hepatitis C virus may improve short-term glucose control among patients with type 2 diabetes, but the long-term impact remains largely unknown. We used data from the Chronic Hepatitis Cohort Study to investigate the impact of sustained virological response on long-term trends in haemoglobin A1c in patients with type 2 diabetes.

Methods: "Index date" was defined as the date of treatment initiation (treated patients) or hepatitis C virus diagnosis (untreated patients). To address treatment selection bias, we used a propensity score approach. We used a piecewise, linear spline, mixed-effects model to evaluate changes in haemoglobin A1c over a 5-year period.

Results: Our sample included 384 hepatitis C virus patients with type 2 diabetes (192 untreated, 192 treated, with sustained virological response or treatment failure). After adjusting for body mass index, haemoglobin A1c was stable among untreated and treatment failure patients. In sustained virological response patients, Hb1Ac trajectories evolved in three phases: (a) index through 6 months post-index, average haemoglobin A1c decreased significantly from 7.7% to 5.4% per 90 days (P < 0.001); (b) 6-30 months post-index, haemoglobin A1c rebounded at a rate of 1.5% every 90 days (P = 0.003); and (c) from 30 months onward, haemoglobin A1c stabilized at an average level of 7.9 (P-value = 0.34). Results from an analysis restricted to patients receiving direct-acting antivirals were consistent with the main findings.

Conclusion: Successful hepatitis C virus treatment among patients with type 2 diabetes significantly reduces HbA1c shortly after treatment, but these decreases are not sustained long-term. Less than three years after sustained virological response, haemoglobin A1c rebounds to levels similar to untreated/treatment failure patients, and higher than recommended for type 2 diabetic maintenance.