(HealthDay News) — After coronary revascularization procedures, the risk of mortality is highest among patients with a low body mass index (BMI). In addition, body composition (lean mass index [LMI] and body fat) may account for the inverse J shape of the mortality curve with increasing BMI. These findings were published online July 16 in the Mayo Clinic Proceedings.

Abhishek Sharma, M.D., from Maimonides Medical Center in Brooklyn, NY, and colleagues conducted a systematic literature review to examine the correlation between BMI and mortality after coronary revascularization procedures (coronary artery bypass grafting and percutaneous coronary intervention). Based on 36 studies, the researchers found that patients with low BMI had the highest risk of total mortality, cardiovascular mortality, and myocardial infarction (relative risks, 2.59, 2.67, and 1.79, respectively), at the end of a mean follow-up of 1.7 years. Overweight patients had the lowest risk of cardiovascular mortality (relative risk, 0.81).

Alban De Schutter, MD, from The University of Queensland School of Medicine in New Orleans, and colleagues conducted a retrospective study involving 47,866 patients with preserved left ventricular ejection fraction. The researchers found that higher BMI was slightly associated with lower mortality (hazard ratio, 0.99; P<0.001). Patients with higher LMI had a lower mortality risk (hazard ratio, 0.71), while the correlation between body fat and lower mortality was only seen without adjustment for LMI (hazard ratio, 0.87; P<0.001 without LMI; hazard ratio, 0.97; P=0.23 with LMI).

“Body composition could explain the inverse J shape of the mortality curve noted with increasing BMI,” the authors write.

Abstract – Sharma
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Abstract – De Schutter
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