Non-adherence to cardiovascular drugs in older patients with depression: A population-based cohort study

Background: Depression is common among patients with cardiovascular disease and has been associated with both drug non-adherence and increased mortality. Non-adherence can occur because of non-initiation, suboptimal implementation, or non-persistence. We aimed to determine if depression increased the risk of any of these components of non-adherence among older patients prescribed cardiovascular drugs in primary care. Methods: A longitudinal analysis of routine primary care data from the Nivel Primary Care Database was performed using data for 2011–2013. A total of 1512 patients aged ≥60 years diagnosed with depression in 2012 were compared with age- and sex-matched groups with either other psychological diagnoses (N = 1457) or mentally healthy controls (N = 1508), resulting in the inclusion of 4477 patients. Non-adherence was classified as non-initiation, suboptimal implementation, or non-persistence. Regression analyses were performed to determine the association between mental health status and non-initiation, suboptimal implementation, and non-persistence. Results: Mixed-effects logistic regression analyses showed increased odds for suboptimal implementation of beta-blockers among depressed patients (2.18; 95% CI 1.29–3.69). For non-persistence, a clustered Cox regression analysis demonstrated that, compared with controls, there was an increased hazard ratio for depressed patients to discontinue beta-blockers (2.31; 95% CI 1.58–3.37) and calcium antagonists (1.74; 95% CI 1.23–2.46). Conclusions: It is likely that older patients in primary care diagnosed with depression are at increased risk of non-persistence with cardiovascular drug therapy. Because non-adherence is associated with increased cardiovascular mortality, it is important that physicians ensure that older depressed patients persevere with therapy.