Objective: To investigate the pattern of postdischarge evidence-based outpatient medication use and its impact on subsequent hospital readmissions in post-acute coronary syndrome (ACS) patients.
Study design: Prospective observational study.
Methods: A telephone survey was conducted to collect information from discharge to 8 months after discharge for 433 patients hospitalized with a primary diagnosis of ACS in 5 mid-Michigan hospitals. The survey data were then merged with chart review data from the initial hospitalization. We first conducted a longitudinal descriptive analysis of the utilization patterns of patient self-reported medication use from discharge to the 8-month survey. Then, multivariable logit analysis was used to estimate the effect of post-ACS medication use on self-reported hospital readmission at 3 months and 8 months after discharge. Propensity score matching was used to counter the possible bias induced by self-selection of outpatient medication use.
Results: The pattern of outpatient medication use was dynamic. Most changes to medication regimens occurred within 3 months after discharge, with fewer changes in the subsequent 5 months. Taking a beta-blocker, angiotensin-converting enzyme inhibitor, or angiotension receptor blocker significantly reduced the probability of hospital readmission 3 months after discharge. Propensity score matching produced similar statistically significant results. Re-hospitalization within 3 months after discharge was a strong predictor of later hospital readmission up to 8 months.
Conclusion: Timely and appropriate medication adjustment in outpatient settings appears to be critically important to reduce hospital readmission among ACS patients.