Economic Impact of Subsequent Depression in Patients With a New Diagnosis of Stable Angina: A Population‐Based Study

BACKGROUND: Depression is strongly linked to increased morbidity and mortality in patients with chronic stable angina; however, its associated healthcare costs have been less well studied. Our objective was to identify the characteristics of chronic stable patients found to have depression and to determine the impact of an occurrence of depression on healthcare costs within 1 year of a diagnosis of stable angina. METHODS AND RESULTS: In this population‐based study conducted in Ontario, Canada, we identified patients diagnosed with stable angina based on angiogram between October 1, 2008, and September 30, 2013. Depression was ascertained by physician billing codes and hospital admission diagnostic codes contained within administrative databases. The primary outcome was cumulative mean 1‐year healthcare costs following index angiogram. Generalized linear models were developed with a logarithmic link and γ distribution to determine predictors of cost. Our cohort included 22 917 patients with chronic stable angina. Patients with depression had significantly higher mean 1‐year healthcare costs ($32 072±$41 963) than patients without depression ($23 021±$25 741). After adjustment for baseline comorbidities, depression was found to be a significant independent predictor of cost, with a cost ratio of 1.33 (95% confidence interval, 1.29–1.37). Higher costs in depressed patients were seen in all healthcare sectors, including acute and ambulatory care. CONCLUSIONS: Depression is an important driver of healthcare costs in patients following a diagnosis of chronic stable angina. Further research is needed to understand whether improvements in the approach to diagnosis and treatment of depression will translate to reduced expenditures in this population.