The obesity paradox in patients with acute coronary syndromes over 2 decades - the ACSIS registry 2000-2018.

Background: Obesity is a worldwide epidemic which is associated with major cardiovascular (CV) risk factors. Nevertheless, substantial distant data, mostly published more than a decade ago, have demonstrated an obesity paradox, where obese patients generally have a better short- and long-term prognosis than do their leaner counterparts with the same CV profile. Nonetheless, it is not fully elucidated whether the obesity paradox is still relevant in the contemporary cardiology era among patients with acute coronary syndrome (ACS). We aimed to examine temporal trends in the clinical outcomes of ACS patients by their BMI status.

Methods: Data from the ACSIS registry including all patients with calculated BMI data between the years 2002-2018. Patients were stratified by BMI groups to underweight, normal, overweight and obese. Clinical endpoints included 30d major cardiovascular events (MACE), and 1-year mortality. Temporal trends were examined in the late (2010-2018) vs. the early period (2002-2008). Multivariable models examined factors associated with clinical outcomes by BMI status.

Results: Among the 13,816 patients from the ACSIS registry with available BMI data, 104 were underweight, 3921 were normal weight, 6224 were overweight and 3567 were obese. 1-year mortality was highest among underweight patients (24.8%), as compared to normal weight patients (10.7%) and lowest among overweight and obese patients (7.1% and 7.5% respectively; p for trend <0.001). 30-day MACE rates followed a similar pattern (24.3% for underweight, 13.6% for normal weight, 11.6% for overweight, and 11.7% for obese; p for trend<0.001). Comparing the 2 time-periods, 30-day MACE was significantly lower in the late period in all BMI groups, but unchanged in patients who were underweight. Similarly, 1-year mortality has decreased in normal weight and obese patients but remained similarly high in underweight patients.

Conclusions: In ACS patients, during 2-decades, 30-day MACE and 1-year mortality were lower among overweight and obese patients compared to underweight and even normal weight patients. Temporal trends revealed that 30-day MACE and 1-year mortality have decreased among all BMI groups other than the underweight ACS patients, among whom the adverse CV rates were consistently high. Our findings suggest that the obesity paradox is still relevant in ACS patients in the current cardiology era.