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. β-blocker therapy reduces sympathetic activity and improves platelet and endothelial function. We investigated if β-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 β-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 β-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 (P(interaction) = 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 β-blockers.