Background: Even mild depressive symptoms during hospitalization are an independent risk factor for mortality after acute coronary syndromes (ACS). The mortality risk is highest for patients whose depressive symptoms persist after ACS. Low adherence to medications that reduce the risk of subsequent cardiac events may be one of the mechanisms underlying the relationship between persistent depression and risk of ACS recurrence. We compared electronically monitored adherence to aspirin in 3 groups of patients with ACS: persistently depressed, remittent depressed, and persistently nondepressed.
Methods: Using an electronic device stored in the cap of a pill bottle, we monitored aspirin adherence over a 3-month period in 165 consecutive patients recruited within 1 week of an ACS event. Depressive symptom severity was assessed by using the Beck Depression Inventory at baseline and at 3 months. Adherence was determined by the percentage of days aspirin was taken as prescribed.
Results: Among the patients, 10.5% of nondepressed patients, 9.8% of remittent depressed patients, and 42.1% of persistently depressed patients took aspirin < or of the time (P < .001). Examined a different way, the mean percentage of days that the correct aspirin dosage (1 pill per day for all patients) was taken was significantly lower in the persistently depressed patients (76.1%) than in the remittent depressed (87.4%) and persistently nondepressed (89.5%) patients (P < .01). Remittent depressed patients did not differ from nondepressed patients. Results remained unchanged after controlling for baseline depressive symptom severity and medical comorbidity.
Conclusions: Poor medication adherence--a potentially modifiable behavior--may contribute to the high mortality risk observed in patients with persistent symptoms of depression after ACS.