The obesity paradox revisited - influence on the results of percutaneous coronary interventions

The "obesity paradox" has been seen in patients with cardiovascular disease. However, the role of the obesity paradox in patients undergoing percutaneous coronary intervention (PCI) is controversial.

Our study aims to investigate the effect of weight categories on mortality in patients undergoing PCI.

The National Inpatient Sample database for the years 2016-2020 was analysed using International Classification of Diseases, Tenth Revision codes in adult patients >18 years of age. Patients undergoing PCI were identified and stratified using weight categories. Univariate and multivariate analyses were performed to assess mortality.

We identified 10,069,454 patients who had undergone PCI. Compared to patients in the normal-weight category, cachectic patients had the highest mortality at 9.78% (odds ratio [OR] 3.88, 95% confidence interval [CI]: 3.65-4.12; p<0.001). Mortality was lowest in overweight patients at 1.28% (OR 0.46, 95% CI: 0.39-0.55; p<0.001), followed by obese patients at 1.61% (OR 0.58, 95% CI: 0.56-0.61; p<0.001). In the morbidly obese category, this protective effect was much less, with mortality being measured at 2.05% (OR 0.75, 95% CI: 0.42-0.78; p<0.001; vs 2.72% in the normal-weight category). After multivariate analysis, mortality remained high in cachectic patients (OR 3.65, 95% CI: 3.42-3.90; p<0.001) and remained low in overweight (OR 0.51, 95% CI: 0.43-0.61; p<0.001) and obese (OR 0.68, 95% CI: 0.66-0.71; p<0.001) patients, but the protective value of weight almost disappeared in the morbidly obese category (OR 0.96, 95% CI: 0.96-1.00; p=0.04).

The obesity paradox held only partially, with the lowest mortality in the overweight category, followed by patients with obesity, then an almost complete loss of protection in those with morbid obesity, and the highest mortality in cachectic patients.