Long-term Survival of Patients With Coronary Artery Disease During the 1970s

A Cohort Study

¹ From the Department of Veterans Affairs Medical Center, the Departments of Medicine and Preventive Medicine, University of Tennessee, Memphis, and Baptist Memorial Hospital Memphis, Tenn.

Study objective: This study was undertaken to determine the effects of altered risk factors and treatment modalities on the short- and long-term survival of patients with documented coronary artery disease whose conditions were diagnosed from 1972 through 1982.

Study design: The study was a retrospective database analysis of clinical, angiographic, and follow-up information.

Setting: Data from all patients referred for cardiac catheterization at the Baptist Memorial Hospital, Memphis, Tenn, were studied.

Patients: Risk factors and survival of patients who underwent cardiac catheterization from 1972 through 1982 and who were followed up for at least 5 years were evaluated. Cohort A included 1,821 patients studied from 1972 through 1977; cohort B included 5,369 patients studied between 1977 and the end of 1982. Each cohort was subdivided based on type of therapy (medical or surgical) that the patients received.

Measurements and results: The 30-day (short-term) and 5-year (long-term) survival rates were compared by life table methods. Short-term survival improved significantly in both medical (from 94.9% to 97.5%, p<0.001) and surgical (from 95.5% to 97.6%, p<0.001) groups from cohort A to cohort B. Long-term survival, however, did not differ significantly between the two cohorts. In the medical group, 5-year survival in cohort A was 86.3% and in cohort B it was 86.9% (p=NS); in the surgical group, in cohort A it was 89.1% while in cohort B it was 89.4% (p=NS). Prevalence of both cigarette smoking and hypercholesterolemia declined significantly from cohort A to cohort B in both surgical and medical groups. However, advanced age, female gender, and previous myocardial infarction were significantly more common in cohort B than in cohort A for both treatment groups.

Conclusions: These results indicate that during the study period, a significant decline in short-term mortality occurred for patients with angiographically documented coronary artery disease. Long-term survival did not, however, improve possibly due to a complex interplay between factors that promote coronary artery disease, eg, cigarette abuse and hypercholesterolemia, and factors that determine survival, eg, increases in age and history of prior infarction and advances in medical and surgical therapy.

Key Words: cardiovascular disease epidemiology • coronary artery disease • survival studies

Submitted on December 14, 1993
Accepted on May 3, 1994