Adherence to Antidepressants and Mortality in Elderly Patients with Cardiovascular Disease

BACKGROUND AND OBJECTIVE: Conflicting findings from studies evaluating the association between use of antidepressant drugs and mortality have been reported. We tested the hypothesis that better adherence to antidepressant therapy may reduce mortality. METHODS: The cohort included 29,845 individuals aged ≥ 65 years from several Italian health units who were newly treated with antidepressant drugs after hospital discharge with a diagnosis for cardiovascular disease during 2008-2010. These individuals were observed from the first prescription until the end of data availability (i.e. 2012-2014, depending on the local database). During this period, information on (1) prescription of antidepressants and other medications and (2) death from any cause (outcome) was recorded. Proportional hazards models were fitted to estimate the association between better adherence to antidepressants (defined as proportion of days covered ≥ 75%) and outcome, by adjusting and stratifying for several covariates. RESULTS: Patients with better adherence to antidepressants had a reduced mortality of 9% (95% CI 3-14). Patients who did not use other medicaments during follow-up had reduced mortality associated with better adherence to antidepressants of 21% (- 1-38), 14% (7-20), 20% (13-26) and 13% (7-19) for no users of antihypertensive agents, lipid-lowering agents, other cardiovascular drugs and antidiabetics, respectively. CONCLUSIONS: Better adherence to antidepressants is associated with reduced all-cause mortality, mainly in patients who did not use other pharmacological treatments. Behavioural changes to enhance adherence among the elderly with cardiovascular disease might offer important benefits in reducing their mortality.