Association between marital status and mortality risk in cardiac disease: a cardiopulmonary exercise testing cohort study

Abstract

Background: Although marital status is a key social determinant of health, its prognostic relevance in cardiopulmonary exercise testing (CPX) cohorts remains unclear. We aimed to evaluate the association between marital status and mortality risk in patients with cardiac disease (CD) who underwent CPX.

Methods: This retrospective, single-center observational study involved consecutive patients with CD who underwent post-discharge CPX between 2008 and 2020. Participants (mean age: 69 years; 73% male) were categorized as either unmarried (never married, divorced, or widowed) or married. The primary outcome was all-cause mortality, and the secondary outcome was cardiovascular mortality. We used Cox proportional hazards models to estimate adjusted hazard ratios (aHRs) and 95% confidence intervals (CIs). Model 1 was adjusted for age and sex to estimate the overall association between marital status and outcomes. Model 2 was adjusted for Model 1 covariates and peak VO₂ to account for objectively measured exercise capacity.

Results: Of 4,681 patients analyzed, 1,117 were unmarried and 3,564 were married. In Model 1, being married was associated with a lower risk of all-cause mortality (aHR: 0.75, 95% CI: 0.62–0.91, P < 0.001). This association persisted after adjusting for peak VO₂ in Model 2 (aHR: 0.79, 95% CI: 0.65–0.96, P = 0.002). For cardiovascular mortality, the estimates were consistent in direction (Model 1; aHR: 0.64, 95% CI: 0.44–0.93, P = 0.019, Model 2; aHR: 0.69, 95% CI: 0.47–1.02, P = 0.061).

Conclusions: In a large CPX cohort of patients with CD, married status was associated with a lower risk of all-cause mortality. The association was attenuated but remained after adjustment for peak VO₂, suggesting that differences in exercise capacity may contribute but do not fully account for the observed association. Marital status should be interpreted as a social marker rather than a causal or interventional exposure, and future studies should clarify modifiable factors related to prognosis.