Peripheral Artery Disease: The Obesity Paradox

Researchers, led by Donna Shu-Han Lin, investigated if the “obesity paradox”—wherein patients with obesity exhibit better survival than normal-weight patients with the same disease—was present in peripheral artery disease (PAD). In their meta-analysis, they observed that mortality was higher in underweight individuals and lower in individuals with obesity among the PAD patient population.

The study, published in the International Journal of Obesity, included 12 articles, encompassing 5,735,578 patients, that reported on mortality outcomes in patients with PAD stratified according to body mass index (BMI). The authors noted that most of the studies used an underweight criteria of a BMI <18.5 kg/m² and an obesity criteria of BMI ≥30 kg/m². The researchers evaluated covariables including age, sex, diabetes mellitus (DM), and presence of coronary artery disease (CAD), and also subgroups based on follow-up length, PAD symptoms, and revascularization modality.

Investigating the Obesity Paradox in Peripheral Artery Disease

In comparing underweight and obesity groups with non-underweight and -obese groups, respectively, the authors surprisingly found that the mortality risk of underweight patients with PAD was significantly higher compared to those who were not underweight (hazard ratio [HR] 1.72; 95% CI, 1.38-2.14; I²=84.2%). Conversely, the mortality risk of patients with PAD with obesity was significantly lower than patients with PAD without obesity (HR 0.78; 95% CI, 0.62–0.97; I²=89.8%). These findings were consistent across covariable and subgroup analyses.

Additionally, the researchers found that the short-term mortality risks for both underweight patients (HR 1.50, 95% CI, 0.47–4.72) and patients with obesity (HR 0.86, 95% CI, 0.66–1.13) did not differ significantly from their non-underweight and non-obese counterparts. Meta-regression analysis found that the association between obesity and improved survival was more pronounced in studies that had a greater proportion of patients with concomitant CAD, the authors noted.

Ultimately, the authors presented their findings as evidence of the apparent presence of the “obesity paradox” in the population of patients with peripheral artery disease. “The mechanisms underlying the obesity paradox in patients with PAD remain to be elucidated, and further evidence is required to guide optimal weight control strategies in these patients,” they closed.

Related: Total Risk for Major Adverse Events in Chronic PAD