Predictive relationship between depression and physical functioning after coronary surgery.

Background: Depression is a prevalent condition in patients undergoing coronary artery bypass graft surgery (CABG) and is often associated with a less favorable health status. The aim of this study was to investigate the relationship between depression and physical functioning in patients undergoing CABG.
Methods: The analyses were based on a sample of 883 consecutive subjects (aged 35-93 years; 19.8% women) undergoing CABG. Depression was assessed using the Patient Health Questionnaire (PHQ); the subscale "physical functioning" was taken from the 36-Item Short-Form Health Survey. Questionnaires were administered 1 to 3 days before surgery (T1) and 2 months (T2) and 1 year (T3) after surgery.
Results: A cross-lagged path analytic model showed that an increase in depressive symptoms predicted a decrease in physical functioning (β(T)₁₋(T)₂ = -0.15 [P < .001]; β(T)₂₋(T)₃= -0.17 [P < .001]), but not the other way around. Multigroup comparisons revealed one moderator effect: in patients with systolic heart failure (left ventricular ejection fraction [LVEF], ≤45%), the effect of depression on physical functioning from T2 to T3 was significantly stronger than in patients with preserved LVEF (β(T)₂₋(T)₃= -0.30 [P < .001] vs β(T)₂₋(T)₃= -0.14 [P < .001]; χ²(diff) = 3.885 [P = .049]).
Conclusions: More attention should be paid to diagnosis and treatment of depression in patients undergoing CABG. After surgery, patients with systolic heart failure and depressive symptoms in particular seem at risk of a deterioration of their physical functioning.