Significance of Comorbid Psychological Stress and Depression on Outcomes After Cardiac Rehabilitation

Background

Depression is associated with increased mortality in stable coronary heart disease. Cardiac rehabilitation and exercise training has been shown to decrease depression, psychological stress, and mortality after a coronary heart disease event. The presence of depression at completion of cardiac rehabilitation and exercise training is associated with increased mortality. However, it is unknown if depression with comorbid psychological risk factors such as anxiety or hostility confers an additional mortality disadvantage. We evaluated the mortality effect of anxiety and hostility on depression after cardiac rehabilitation and exercise training.

Patients and Methods

We studied 1150 patients with coronary heart disease following major coronary heart disease events who had completed formal cardiac rehabilitation and exercise training. Using Kellner questionnaires, stress levels were measured in 1 of 3 domains: anxiety, hostility, and depression (with an aggregated overall psychological stress score) and divided into 3 groups: nondepressed (n = 1072), depression alone (n = 18), and depression with anxiety or hostility (n = 60). Subjects were analyzed for all-cause mortality over 161 months of follow-up (mean 6.4 years) by National Death Index.

Results

Depression after cardiac rehabilitation was not common (6.8%; mortality 20.8%) but when present, frequently associated with either anxiety or hostility (77% of depressed patients; mortality 22.0%). After adjustment for age, sex, ejection fraction, and baseline peak oxygen consumption, depression alone (hazard ratio HR] 1.73, P = .04), as well as depression with comorbid psychological stress, was associated with higher mortality (HR 1.98, P = .03). Furthermore, our data showed an increased mortality when both anxiety and hostility were present in addition to depression after cardiac rehabilitation (HR 2.41, P = .04).

Conclusions

After cardiac rehabilitation, depression, when present, is usually associated with other forms of psychological stress, which confers additional mortality. More measures are needed to address psychological stress after cardiac rehabilitation.