Prognostic impact of different regional referral practices for interventional investigation and coronary treatment after exercise testing: A population-based 5-year follow-up study

Abstract

Objective. To examine the association among different centres' referral practices for coronary angiography (CAG) after exercise testing, with 1- and 5-year outcomes. Design. Observational population-based cohort study. Setting. All 10 hospitals and six private practising consultants in Aarhus and Ringkjoebing counties (900 000 inhabitants), Denmark. Subjects. All patients who in 1996 had an abnormal bicycle exercise test (n = 736). Measurements. Referral for CAG, coronary intervention, cardiovascular and all-cause mortality, and myocardial infarction (MI). Results. As an immediate consequence of the exercise test, 60.7% of subjects were referred for CAG. Based on the centres' fraction of patients referred for CAG, three categories of centres were defined: low (<33%), intermediate (33-66%) and high (>66%). A low compared with a high referral fraction was associated with a similar 5-year mortality and MI ratio [all-cause/cardiovascular mortality rate ratio (RR) = 1.33, 95% confidence interval (CI): 0.45-3.92/RR = 0.62, 95% CI: 0.25-1.57; and MI RR = 0.92, 95% CI: 0.45-1.86]. The same was found for an intermediate compared with a high fraction (all-cause/ cardiovascular mortality RR = 0.92, 95% CI: 0.49-1.72/RR = 0.74, 95% CI: 0.42-1.33; and MI RR = 1.07, 95% CI: 0.68-1.70). Estimates were about the same after 1 year of follow-up with no major differences among centres in mortality or MI. Conclusions. Centres' different referral practices for interventional investigation and treatment were not associated significantly with short-term or long-term mortality or MI among patients with an abnormal exercise test.