Aspirin may reduce depressive symptoms in survivors of ACS

Aspirin has been commonly used for prevention of cardiovascular disease. Depression has been found to be an important prognostic factor after heart attacks. But what is their relationship? This is addressed by a study published in the 5^th 2011 issue of Psychotherapy and Psychosomatics.

In survivors of acute coronary syndromes (ACS;unstable angina or myocardial infarction), depression is highly prevalent and increases the risk of adverse medical outcomes, independent of other prognostic risk markers. After ACS, adherence to recommended medications (e.g. aspirin,statins and β-blockers) is crucial to prevent recurrent events or mortality, yet rates of adherence to these medications are poor. Depressed patients are especially likely to be poorly adherent.

Thus, poor medication adherence may explain some of the increased risk of depression and adverse clinical outcomes after ACS. The investigators used data from 168 participants in the medication monitoring substudy of the observational Coronary Psychosocial Evaluation Studies (COPES) to test this hypothesis. This substudy included hospitalized ACS patients who were prescribed a daily dose of aspirin, neither used a weekly pillbox nor lived in a nursing home, and had a score of ≥10 or < 5 on the Beck Depression Inventory. Aspirin adherence over 90 days after hospital discharge was measured using the Medication Event Monitoring System (MEMS) device. Each time the MEMS bottle is opened, the date and time is permanently recorded on a computer chip in the cap. Patients received a 90-day supply of their prescribed aspirin dose in an MEMS bottle. They were informed that their adherence was being monitored, but they did not receive adherence counseling. The outcome was the 1-year first occurrence of a major adverse cardiac event (MACE; nonfatal myocardial infarction, urgent cardiac revascularization or unstable angina hospitalization) or all-cause mortality (ACM). Adherence, defined as the percentage of days the correct number of pills was taken, was computed across the first 7 days after discharge, the first month and the first 3 months. The COPES parent study included 457 ACS patients, of which 172 took part in the aspirin monitoring study. Controlling for age, sex and site, baseline depressive symptoms were significantly correlated with poorer 7-day, 1-month and 3-month aspirin adherence (p <0.02). After 1 year, there had been 14 MACE/ACM events (8%). Adjusting for age, sex and site, poorer 7-day and 1-month aspirin adherence as well as baseline depressive symptoms were each individually associated with 1-year MACE/ACM. A similar, yet non significant association was found for poorer 3-month aspirin adherence (p =0.054). When both baseline depressive symptoms and 7-day aspirin adherence were entered into the age- and sex-adjusted model, the HR for depressive symptoms decreased substantially, whereas poorer 7-day aspirin adherence remained a significant predictor. The effect size for depressive symptoms decreased by 31% when 7-day aspirin adherence was included in the analysis. Similarly, poorer 1-month aspirin adherence decreased the effect size for baseline depressive symptoms by 29%.

Depression in cardiac patients has been linked to several biological and behavioral dysregulations. The present study shows that a modifiable patient behavior - medication adherence - may account for some of the clinical outcome risk associated with increased depressive symptoms after ACS. Generalizability of the current study is limited by the relatively small sample size. Also, the study participants had lower levels of depressive symptoms than the study refusers, and the restriction of range may have attenuated both the associations between adherence and depression, and between depressive symptoms and MACE/ACM. It also remains to be shown whether poor aspirin adherence is a marker of overall poor medication adherence across all cardioprotective medications. Lastly, it is possible that aspirin, due to anti-inflammatory effects, may reduce depressive symptoms.

In conclusion, this study provides evidence that poorer aspirin adherence may account for a substantial part of the excess prognostic risk associated with depressive symptoms after ACS. Promoting medication adherence in combination with depression treatment may more effectively improve the medical prognosis for depressed patients than simply treating depression.