Abstract

Background: Coronary artery disease (CAD) and depression often coexist, complicating disease management and worsening prognoses. Depression significantly increases mortality risk in CAD patients, but the impact of depression onset timing on long-term mortality in 2-year survival CAD patients remains unclear.

Methods: This retrospective cohort study used data from Taiwan's National Health Insurance Research Database from January 1, 2007, to December 31, 2014, including 1,254,084 individuals in the "no depression" group, 14,554 individuals in the "before CAD" group, 1,839 individuals in the "within one month" group, and 17,427 individuals in the "after one month" group between 2008 and 2010, with excluding mortal individuals within 2 years of CAD. It assessed all-cause mortality, CAD-specific mortality, all-cause hospitalization, and CAD-specific hospitalization over a two-year follow-up period.

Results: Hazard ratios (HRs) for all-cause mortality were lower in the "before CAD" (HR 0.93, 95% CI 0.89–0.97), "within one month" (HR 0.76, 95% CI 0.67–0.87), and "after one month" (HR 0.52, 95% CI 0.49–0.54) groups compared to the "no depression" group. Women had significantly lower HRs for all-cause and CAD-specific mortality. The "after one month" group showed a higher risk for all-cause hospitalization. Socioeconomic status, comorbidities, and age significantly influenced outcomes.

Conclusion: Depression in CAD patients who survived beyond two years appeared to confer a protective effect on mortality. These findings suggest that there may be other confounding factors that influence the prognosis of 2-year survival CAD patients. Further researchmay explore the mechanisms  underlying these protective effects to improve clinical practices.