Survival trends among Danish patients undergoing coronary angiography for known or suspected ischaemic heart disease: a population based follow up study, 1992–2000

Objective: To determine, from population based clinical data, changes in the survival of Danish patients examined by coronary angiography for known or suspected ischaemic heart disease (IHD) during the 1990s. Design: Follow up study. Setting: The departments of cardiology at Rigshospitalet, Copenhagen University Hospital, and Skejby Hospital, Aarhus University Hospital, Denmark. Patients: Patients with IHD (n  =  7021) who underwent first time coronary angiography in 1992, 1996, or 2000. Main outcomes measures: Three year survival was compared between cohorts and with that of the general population. Cox proportional hazards regression was used to estimate mortality ratios adjusted for differences in patient characteristics. Results: Survival improved substantially—for example, adjusted mortality ratio was 0.69 (95% confidence interval (CI) 0.55 to 0.87) when comparing patients from 2000 with patients from 1992. The absolute standardised survival rates after three years of follow up were 87.1% (95% CI 85.4% to 88.8%), 89.9% (95% CI 88.5% to 91.3%), and 91.2% (95% CI 90.3% to 92.1%) among patients examined in 1992, 1996, and 2000, respectively. The improvement was not explained by the improvement in overall survival in the general population during the study period. Conclusions: The survival of Danish patients with known or suspected IHD appears to have improved substantially during the 1990s.