Association Between Lipid Testing and Statin Adherence in the Veterans Affairs Health System

Background: Measurement with a lipid panel after statin initiation and in long-term follow-up is recommended in both 2013 and 2018 cholesterol guidelines to assess statin efficacy and adherence. We assessed whether routine laboratory evaluation with lipid panels is associated with greater statin adherence. Methods: We identified patients with atherosclerotic cardiovascular disease within the entire Veterans Affairs (VA) health care system with at least one primary care visit between October 2013 and September 2014, who were on statin therapy (n = 813,887; n = 52,583 for new statin users). Statin adherence was determined using medication refill data and assessed by proportion of days covered (PDC). Association between number of lipid panels completed and PDC was assessed with adjusted regression models. Results: Within the study period, the mean number of lipid panels that were completed per patient was 1.5 ± 1.0. In the overall cohort, percentage of statin users with PDC ≥ 80% was 66.0% for patients with ≥ 1 lipid panel and 61.2% for patients with 0 lipid panels (P <.0001). Among new statin users, PDC ≥ 80% was 68.0% for patients with lipid panels completed within 4-12 weeks of therapy initiation and 59.3% for those without lipid panels completed within the timeframe (P <.0001). In adjusted analysis, number of lipid panels completed was associated with a modest but significant increase in PDC, when PDC was evaluated as a continuous (beta-coefficient 0.0054, P <.001) or categorical (PDC ≥ 80% [odds ratio (OR) 1.01; 95% confidence interval (CI), 1.00-1.01]) measure of statin adherence. The significant association was also observed in new users (beta-coefficient 0.0058, P <.001; OR 1.02; 95% CI, 1.00-1.03). Conclusion: Routine, guideline-directed completion of lipid panels in atherosclerotic cardiovascular disease patients on statins overall and among new statin users is associated with a modes6t but significant increase in statin adherence.