Class I Obesity is Associated With Decreased Risk of Stroke After Carotid Endarterectomy

Abstract

Although obesity is a risk factor for vascular disease, previous studies have shown an obesity paradox, with decreased death in obese patients undergoing vascular surgery. This study examined the relationship between body mass index (BMI) and outcomes after carotid endarterectomy (CEA). The 2005 to 2009 American College of Surgeons National Surgical Quality Improvement Program (ACSNSQIP) database was queried to evaluate 30-day outcomes after isolated CEA across National Institutes of Health-defined obesity classes, defined by body mass index (BMI) in kg/m2 as underweight, BMI <18.5; normal weight, BMI 18.5 to 24.9; overweight, BMI 25.0 to 29.9; class I obese, BMI 30.0 to 34.9; class II obese, BMI 35.0 to 39.9; or class III obese, BMI ≥40). The association of BMI with morbidity and death was assessed with multivariable logistic regression, adjusting for preoperative and operative characteristics and polyvascular disease. In the cohort of 23,663 CEA, the overall stroke and mortality rates were 1.4% and 0.6%, respectively. On multivariable analysis, class I obesity was the only variable associated with decreased risk of stroke (odds ratio [OR], 0.54; 95% confidence interval [CI], 0.34-0.84; P = .006). Independent risk factors for stroke were female sex (OR, 1.37; P = .018), previous transient ischemic attack (OR, 1.38; P = .02), previous stroke with (OR, 1.59; P = .02) or without (OR, 1.73; P = .008) neurologic deficit, and hemiplegia (OR, 2.17; P = .002). Class II (OR, 2.41; 95% CI, 1.18-4.89; P = .015) and III obesity (OR, 2.58; 95% CI, 1.11-6.03; P = .028) were associated with increased risk of surgical site infection. Obesity was not an independent predictor of death or myocardial infarction. Independent predictors of death were increasing age (OR, 1.18, P = .005), previous stroke with neurologic deficit (OR, 1.71; P = .035), previous surgery for peripheral vascular disease (OR, 2.23; P = .002), chronic obstructive pulmonary disease (OR, 3.13; P < .001), dependent status (OR, 3.74; P < .001), previous myocardial infarction (OR, 5.07; P < .001), and acute renal failure (OR, 9.66; P = .005). An obesity paradox exists for stroke, but not death, after CEA. Reduced risk of stroke in class I obese patients was independent of polyvascular disease, preoperative comorbidities, and operative variables.