Estimation of contribution of changes in coronary care to improving survival, event rates, and coronary heart disease mortality across the WHO MONICA Project populations

Abstract

Background The revolution in coronary care in the mid-1980s to mid-1990s corresponded with monitoring of coronary heart disease (CHD) in 31 populations of the WHO MONICA Project. We studied the impact of this revolution on coronary endpoints. Methods Case fatality, coronary-event rates, and CHD mortality were monitored in men and women aged 35–64 years in two separate 3–4-year periods. In each period, we recorded percentage use of eight treatments: coronary-artery reperfusion before, thrombolytics during, and β-blockers, antiplatelet drugs, and angiotensin-converting-enzyme (ACE) inhibitors before and during non-fatal myocardial infarction. Values were averaged to produce treatment scores. We correlated changes across populations, and regressed changes in coronary endpoints on changes in treatment scores. Findings Treatment changes correlated positively with each other but inversely with change in coronary endpoints. By regression, for the common average treatment change of 20, case fatality fell by 19% (95% Cl 12–26) in men and 16% (5–27) in women; coronary-event rates fell by 25% (16–35) and 23% (7–39); and CHD mortality rates fell by 42% (31–53) and 34% (17–50). The regression model explained an estimated 61% and 41% of variance for men and women in trends for case fatality, 52% and 30% for coronary-event rates, and 72% and 56% for CHD mortality. Interpretation Changes in coronary care and secondary prevention were strongly linked with declining coronary endpoints. Scores and benefits followed a geographical east-to-west gradient. The apparent effects of the treatment might be exaggerated by other changes in economically successful populations, so their specificity needs further assessment.