The Impact of Obesity on Long-term Survival After Coronary Artery Bypass Grafting¹

Background

Obesity is a well-known risk factor for coronary artery disease. The objective of our study was to examine the impact of obesity on long-term survival after coronary artery bypass grafting (CABG).

Materials and Methods

Using prospectively gathered data, we reviewed records of 1163 consecutive patients who underwent isolated primary CABG between 1997 and 2007. We compared outcomes of obese patients (body mass index [BMI] ≥ 30 kg/m²; n = 472) and non-obese patients (BMI < 30 kg/m²; n = 691). Long-term survival was assessed by using Kaplan-Meier curves generated by log-rank tests and adjusted for confounding factors with Cox logistic regression analysis.

Results

Obese patients were slightly younger (60 ± 8 versus 63 ± 9y; P < 0.0001), were less likely to be current tobacco smokers (30% versus 41%; P < 0.0001), had a higher incidence of diabetes (51% versus 33%; P < 0.0001), and had a lower incidence of cerebral vascular disease (18% versus 24%; P = 0.009) than non-obese patients. The two groups of patients had similar 30-d rates of mortality (1.3% versus 1.5%; P = 0.8) and major adverse cardiac events (2.3% versus 2.5%; P = 0.9). Adjusted Cox regression survival curves were also similar between the two groups of patients (adjusted hazard ratio, 1.2; 95% confidence interval, 0.8–1.8; P = 0.28).

Conclusions

Obese patients who underwent CABG had 30-d mortality rates and early outcomes similar to those of non-obese patients. Long-term survival was also similar between these two groups of patients after adjustment for confounding variables.

Key Words: body mass index, coronary artery bypass grafting, obesity, outcomes, survival