Predictors and Outcomes Associated with Clinically Significant Improvements in Anxiety and Depression Symptoms Following Cardiac Rehabilitation

BACKGROUND: Cardiac rehabilitation (CR) participation improves depressive and anxious symptoms post-coronary catheterization, yet it is unclear to what extent improvements are clinically significant. This study characterized the proportion of patients achieving a minimal clinically important difference (MCID) on the Hospital Anxiety and Depression scale (HADS) following CR and evaluated associations between MCID, patient characteristics, and mortality. METHODS: A retrospective analysis of data was conducted at a large Canadian CR centre. Patients were adults (18+) who participated in CR post-coronary catheterization. HADS and risk factor data were assessed at baseline and 12-weeks. MCID was defined as ≥1.7-point decrease in HADS-Depression or HADS-Anxiety. Univariate and multivariable logistic regressions and Cox proportional analyses were performed. RESULTS: Among 2,702 patients (60.2±10.4 years old, 20.0% female), 29.8% and 36.6% achieved MCID in depressive or anxious symptoms, respectively. In subsamples of patients with elevated baseline HADS symptoms i.e., HADS-Depression (n=339) or HADS-anxiety (n=848); subscale scores ≥8, more than half reached the MCID threshold (60.5% and 57.0%, respectively). Factors associated with depressive symptom improvement included younger age and higher baseline HADS. Younger age, lower BMI, higher total cholesterol, and higher baseline HADS were associated with improved anxious symptoms. Achieving an MCID in depressive or anxious symptoms did not predict improved survival. CONCLUSIONS: More than one-in-two patients with elevated baseline HADS experienced a clinically meaningful improvement in depressive and anxious symptoms. More research is needed to understand the impact of clinically relevant improvement in psychological symptoms on survival post-coronary catheterization.