Predictors and Outcomes Associated with Improvements in Anxiety and Depressed Mood Among Patients Who Complete Cardiac Rehabilitation

Abstract

Background: Cardiac rehabilitation (CR) is an established treatment for coronary artery disease (CAD) that may also improve psychological functioning. However, the extent to which reductions in depressive and anxious symptoms are clinically meaningful remains unclear. This study examined the proportion of patients achieving a minimal clinically important difference (MCID) on the Hospital Anxiety and Depression Scale (HADS) following CR completion and whether these differences are associated with patient characteristics and subsequent mortality. Methods: Retrospective analyses were performed on data from an observational cohort study of CAD patients following coronary catheterization who completed a 12-week CR program during 2009-2019 (TotalCardiologyTM Rehabilitation, Calgary). Patient characteristics and depressive and anxious symptom severity were measured at baseline and post-CR. Mortality data were extracted from Alberta Vital Statistics. A MCID in depressive and anxious symptoms was indicated by an established cut-off (>1.7 decrease in HADS-Anxiety or HADS-Depression scores). Results: Among 6,208 patients (60.5 ± 10.8 years, 20.8% female), 13.0% and 15.9% achieved clinically significant reductions in HADS-Depression and HADS-Anxiety scores, respectively. In patients with baseline HADS-Depression >8 (n = 657), 31.2% reported improved severity of depressive symptoms. In patients with baseline HADS-Anxiety >8 (n = 1,509), 32.0% reported improved severity of anxious symptoms. Higher baseline anxious symptoms, depressive symptoms, and younger age were associated with a greater likelihood of improvements in depressive symptoms (OR = 0.98, 95% CI [0.97–0.99]) and anxiety (OR = 0.99 [0.98, 0.99]). Higher baseline cardiorespiratory fitness (OR = 1.03 [1.00, 1.06]) and higher baseline hemoglobin A1C (OR = 1.00 [1.00, 1.00]) were associated with improvements in anxiety. A reduction in anxiety during CR was associated with lower all-cause mortality at 3-year follow-up (HR = 0.12, [0.02, 0.88]) in patients with elevated baseline anxiety symptoms. Conclusion: CR completion is associated with improved depressive and anxious symptoms in one-third of patients, which could translate to improved health outcomes. A considerable subset of program completers remained symptomatic and may require targeted psychological intervention. Age, cardiorespiratory fitness, blood sugar control, and baseline mood/anxiety symptoms might contribute to differential treatment response.