On-site programmatic attendance to cardiac rehabilitation and the healthy-adherer effect.

BACKGROUND: On-site attendance to prescheduled cardiac rehabilitation visits has been shown to be associated with improved outcomes following cardiac rehabilitation. The extent to which on-site programmatic attendance represents a healthy-adherer effect remains unknown.
METHODS: This retrospective cohort study consisted of 17,000 consecutively referred patients to a cardiac rehabilitation program in Ontario, Canada. On-site attendance at prescheduled visits was our primary exposure variable. The primary outcome was all-cause death or hospitalization at two years following the expected program completion date, irrespective of drop-out. Secondary outcomes included adherence to statins, health-seeking preventative health visits, and changes in clinical risk-profiles. Cox proportional hazards adjusted for baseline sociodemographic, clinical and comorbid characteristics.
RESULTS: Among the 12,440 patients who attended at least one prescheduled on-site visit, on-site attendance was inversely correlated with baseline smoking rates and body mass index at program entry. After adjustment for baseline factors, the risk of death or hospitalization progressively fell with incremental increases in on-site attendance (adjusted hazard ratio for each 10% increase in on-site attendance: 0.96; 95% confidence interval: 0.93-0.99, p = 0.007). Such associations were driven predominantly by differences in non-cardiovascular hospitalizations. Incremental increases in on-site attendance were associated with improvements in cardiopulmonary fitness and body mass index (both p < 0.001), better attendance of preventative care physician visits (p < 0.001) and higher medication adherence to statins (p = 0.007).
CONCLUSIONS: Associations between on-site attendance at cardiac rehabilitation and outcomes may represent a healthy-adherer effect. Future research must evaluate the clinical utility of on-site attendance as a behavioral health-adherence metric for cardiac rehabilitation monitoring and surveillance. © The European Society of Cardiology 2014.