Missed opportunity: a clinical data linkage study of guideline-directed medical therapy and clinical outcomes of patients discharged with acute coronary syndrome who attended cardiac rehabilitation programs

Background: Although guidelines recommend guideline-directed medical therapy (GDMT) for patients with acute coronary syndrome (ACS), implementation is limited in clinical practice. Aim: To assess the level of GDMT in ACS patients after discharge who attended cardiac rehabilitation (CR) programs and association with clinical outcomes. Method: A cross-sectional study was conducted in 13 rural and 10 metropolitan CR programs via all modes of delivery (face-to-face, telephone, or general practice-hybrid) operating in South Australia, Australia. ACS patients were included if they were >= 18 years of age and were referred and attended CR programs with medication details recorded in their hospital discharge summary. GDMT was assessed according to the Australian clinical guidelines for the management of acute coronary syndromes 2016. Prescription of all the four recommended medication classes was considered optimal. Logistic regression and chi(2) test were used for association. Results: Of the 1229 patients included, 74.6% were male and 41.1% had acute myocardial infarction. Only 39.7% of patients received optimal prescription. Prescription of any three or two medication class combinations occurred for 78.3% and 94.1% of patients, respectively. Optimal GDMT was associated with fewer hospital admissions (odds ratio = 0.647, 95% confidence interval 0.424-0.987, p = 0.043) with no significant gender association. Women were less likely to be prescribed angiotensin converting enzyme inhibitors (p = 0.003), angiotensin receptor blockers (p = 0.007), statins (p = 0.005), and any two (p < 0.001) and three combinations (p = 0.023) of medication classes. Conclusion: GDMT prescription was suboptimal in patients with ACS before attendance at CR. Primary care and CR clinicians have missed an opportunity to implement best practice guideline recommendations, particularly for women.