Physical activity and risk of all-cause mortality in patients with stable angina pectoris: Effect modification by β-blocker treatment

Background: Physical activity (PA) influences sympathetic stimulation, platelet activation as well as vascular function, and has been associated with improved health outcomes in patients with coronary heart disease. beta-blocker therapy reduces sympathetic activity and improves platelet and endothelial function. We investigated if beta-blocker treatment modifies the association of self-reported PA with the risk of all-cause mortality. Methods: A total of 2284 patients undergoing elective coronary angiography for suspected stable angina pectoris (SAP) were studied. Using Cox modeling, we examined associations between PA (categorized as 'sedentary/inactive', 'low', 'moderate', and 'high') and all-cause mortality according to beta-blocker therapy. Results: During a median follow-up of 10.3 years, 390 patients (17.1%) died. Higher PA was generally associated with a more favorable cardiovascular risk profile. Compared to the patients who were sedentary or inactive, the age and sex adjusted HRs (95% CI) for all-cause mortality were 0.89 (0.66-1.20), 0.73 (0.57-0.95) and 0.72 (0.55-0.95) in the low, moderate and high PA group, respectively. However, and notably, these risk estimates were 0.85 (0.60-1.20), 0.65 (0.47-0.89) and 0.58 (0.41-0.81) in beta-blocker treated subjects vs. 1.00 (0.57-1.78), 0.96 (0.61-1.52) and 1.20 (0.74-1.95) in non-treated groups (Pinteraction = 0.018). The results were essentially similar in the multivariable adjusted models. Conclusions: In patients with suspected SAP, increased PA was associated with reduced mortality risk primarily in patients treated with beta-blockers.