Depression and anxiety lead to increased morbidity and mortality in patients with coronary artery disease (CAD). Medication nonadherence is one possible pathway contributing to adverse outcome, but it is unknown how either depression or anxiety itself influences adherence compared to combined depressive-anxious comorbidity. The aim of the study was to evaluate the influence of simultaneous depressive and anxious symptoms on medication adherence in patients with stable CAD.
Between 02/2009 and 06/2010 we examined the association between current depressive and anxious symptoms with medication nonadherence in a cross-sectional study of 606 inpatients with stable CAD. Symptoms were assessed by using the Hospital Anxiety and Depression Scale. Morisky Medical Adherence Scale measured medication adherence.
Depressive and anxious symptoms were weakly and independently associated with medication nonadherence (r=0.28, p<0.01 and r=0.27, p<0.01 respectively). Compared to non-depressed, patients with depressive symptoms had an up to 3.6-fold odds, those with anxious symptoms an up to 3.2-fold odds of nonadherence. The presence of combined anxiety and depressive symptoms was also weakly correlated with adherence (r=0.30, p<0.01). The risk for nonadherence in patients suffering from both anxiety and depression was up to 4.4 times higher compared to patients without symptoms.
Apart from depressive symptoms, anxiety is a second important and independent marker for nonadherence in patients with coronary artery disease. The negative effect of anxiety on medication adherence increases in case of comorbid depressive symptoms. Future studies addressing medication adherence should focus more on anxious-depressive comorbidity than on singular depressive or anxious symptoms.