Objective

• Assess the impact of this change on adherence to essential medication in patients with acute coronary syndrome (ACS) in the region of Valencia.

Effect of cost sharing on adherence to evidence-based medications in patients with acute coronary syndrome.

• Cost-sharing scheme for pharmaceuticals in Spain changed in July 2012. Our aim was to assess the impact of this change on adherence to essential medication in patients with acute coronary syndrome (ACS) in the region of Valencia.
   
• Results: Cost-sharing change made no significant differences in adherence between intervention and control groups for essential medications with low price and low patient maximum coinsurance, such as antiplatelet and beta-blockers. For costlier ACE inhibitor or an angiotensin II receptor blocker (ACEI/ARB) and statins, it had an immediate effect in the proportion of adherence in the pensioner group as compared with the control group (6.8% and 8.3% decrease of adherence, respectively, p<0.01 for both). Adherence to statins decreased for the middle-income to high-income group as compared with the control group (7.8% increase of non-adherence, p<0.01). These effects seemed temporary.
   
• Conclusion: Coinsurance changes may lead to decreased adherence to proven, effective therapies, especially for higher priced agents with higher patient cost share. Consideration should be given to fully exempt high-risk patients from drug cost sharing.