Reimbursement restrictions reduce liver fibrosis screening in adults with diabetes in Ontario: a population-based interrupted time series analysis

Adults with type 2 diabetes have increased risk of liver fibrosis, leading guidelines to recommend screening with the Fibrosis-4 Index (FIB-4). We assessed if modifications to Ontario Health Insurance Plan coverage of aspartate aminotransferase (AST) tests in 2013 were associated with changes in liver fibrosis assessment rates among adults with diabetes. This population-based cohort study included adults with diabetes and no history of liver disease in Ontario, Canada, from 2010 to 2022. Policy periods were constructed based on AST reimbursement practices. The primary outcome was the receipt of all laboratory tests needed to calculate FIB-4 (AST, alanine aminotransferase, and platelet count). Modified Poisson regression estimated the adjusted risk ratios (aRRs) for predictors of receiving liver fibrosis assessment. Interrupted time series analysis employed autoregressive integrated moving average models to assess both immediate and sustained policy effects. This study included 1,680,451 individuals; 47% were female; median age was 64 years [IQR, 55–73 years]. The annual proportion without any testing ranged from 39 to 47%. The risk of receiving all required tests for FIB-4 declined significantly: 12.7% (aRR 0.873, 0.869–0.877) during implementation, 33.9% (aRR 0.661, 0.657–0.664) post-intervention, and 63.1% (aRR 0.369, 0.366–0.371) COVID-19. Interrupted time-series analysis showed a significant immediate decline in monthly testing of FIB-4 components (− 0.38; 95% CI − 0.59 to − 0.18), followed by a continued monthly decrease (− 0.03; 95% CI − 0.07 to 0.01). Restricting AST reimbursement was associated with a decline in liver fibrosis assessments for people with diabetes despite increasing consensus in favor of preventative screening.