The association between obesity and coronary artery disease detected during non-emergent angiography: A comparison between black and white patients
Creators: name: Stalls, Caleb
Publisher: name: The University of North Carolina at Chapel Hill University Libraries
Year: 2011

description: Introduction: Despite known associations between obesity and the development of cardiovascular disease, the relationship between obesity as reflected by BMI and angiographically demonstrated CAD is not fully understood. Moreover, this relationship has not been adequately defined in black patients, a group demonstrated to have lower rates of angiographic CAD despite higher rates of traditional CAD risk factors, cardiovascular events, and CAD-related mortality. In order to more fully characterize the association between obesity, race, and CAD, a systematic review and subsequent analysis of secondary data from a major academic medical center was performed. The review informed the approach to the analysis and underscores the significance of the resulting manuscript—with potentially important clinical implications in the evaluation and management of patients with suspected CAD. Methods: The review canvassed literature using multiple academic search engines. The contribution of obesity to black-white differences in angiographically demonstrated CAD proved too narrow a topic for an adequate systematic review; therefore the study focus was broadened to include articles evaluating the relationship between BMI and CAD. Potential studies for full review were narrowed using appropriate inclusion and exclusion criteria. Systematic data extraction facilitated the organized comparison of internal and external validity, strength of evidence, and overall quality of selected studies. The secondary data analysis was performed using an angiography database from a single academic hospital. We studied patients undergoing first-time, non-emergent angiography from 2001 to 2010. From this cohort, we selected those lacking a previous CAD diagnosis, without previous cardiac intervention, and with complete anthropomorphic measures and outcome data. Using models that controlled for patient demographics and CAD risk factors, we compared rates of angiographic disease for blacks and whites by obesity status (BMI ≥ 30 kg/m2) and BMI class. Significant CAD was defined by the presence of a significant lesion (≥50% stenosis in the left main artery or ≥70% stenosis elsewhere), and also quantified by a modified Gensini score of global disease. Results: The review found three out of five studies to lack sufficient, overall quality as to draw reliable conclusions from their results. The two stronger studies found no consistent relationship between BMI and CAD, with statistically nonsignificant inverse relationships. In preparation for the original manuscript’s analysis, we identified 4,022 white and 1,963 black eligible patients. Black patients had higher rates of diabetes and hypertension, and were more likely to be obese than whites (OR 1.85;95% CI 1.65-2.06). Nevertheless, black patients were less likely to have a significant stenosis (adjusted OR 0.57; 95% CI 0.48–0.66), and were found to have a lower mean Gensini score (7.33 vs. 8.83, P=0.001). Obesity was not associated with the presence of CAD. In fact, black obese patients were significantly less likely to have a severe stenosis than their non-obese counterparts, and there was a non-significant trend for obese patients of both races to have less disease than non-obese patients using the Gensini score. Conclusions: The literature is underfunded with evidence describing the relationship between obesity, race, and CAD. Previous studies suggest there is no association between obesity and CAD despite ultimately higher rates of cardiac morbidity and mortality in the obese. Black patients in this study’s cohort were more likely to be obese than white patients yet were far less likely to have significant CAD. Moreover, obesity itself was not positively associated with the presence or severity of CAD, suggesting that obesity may lead to cardiovascular morbidity and mortality by mechanisms other than the development of atherosclerosis, particularly in black patients.