Cardiomegaly on chest x-ray: prognostic implications from a ten-year cohort study of elderly subjects: a report from the Bronx Longitudinal Aging Study.

This report is from a 10-year cohort study of community-dwelling elderly men and women. Mean age at the time of entry into the study was 79 years. Annual chest x-ray studies were performed, and data are presented regarding prevalence, incidence, and prognosis of cardiomegaly. Cardiomegaly was defined as a transverse diameter of the cardiac silhouette greater than or equal to 50% of the transverse diameter of the chest (increased cardiothoracic ratio). At the time of entry into the study 110 subjects (23%) had cardiomegaly. After 10 years, 51% of the subjects with cardiomegaly at baseline died compared with 33% of the subjects without cardiomegaly (mortality rate = 9.1 vs 4.8/100 person-years respectively; p = 0.014). Cardiovascular disease incidence was also higher for those with preexisting cardiomegaly at baseline (rate 9.1 vs 6.1/100 person-years; p = 0.0001). According to the Cox proportional hazards regression analysis, age, cardiomegaly, diabetes, and prior evidence of myocardial infarction were independent predictors for death in this cohort. Similarly, the best predictive variables for cardiovascular disease were age, diabetes, prior evidence of myocardial infarction, and cigarette smoking. Of the 359 subjects without cardiomegaly at baseline, 108 (30%) showed evidence of new cardiomegaly, and their risk of cardiovascular disease was 1.8 times that of subjects whose test results were negative for cardiomegaly throughout the study (p = 0.003). Thus cardiomegaly, as defined by an increased cardiothoracic ratio on x-ray films, irrespective of cause, is associated with a poor prognosis in very elderly men and women.