Relationship Between Body Mass Index and Outcomes in Acute Myocardial Infarction.

Background: The prevalence of obesity in the United States is high. Obesity is one of the leading risk factors in the development of acute myocardial infarction (AMI). Nevertheless, how obesity impacts AMI in-hospital outcomes remains controversial.

Methods: Using National Inpatient Sample (NIS) database, we identified patients diagnosed with AMI from the year 2015 to 2018. We divided these patients into five subgroups based on their body mass index (BMI). We compared outcomes such as mortality, length of inpatient stay, and inpatient complications between our subgroups. Statistical analysis was done using the program STATA. Our nationally representative analysis included 561,535 patients who had an AMI event across various weight classes.

Results: Most of our sample was obese (BMI > 30 kg/m) and male. Obese patients were significantly younger than the rest. Length of stay (LOS) for AMI was highest for those with a BMI of less than 24 kg/m. In-hospital mortality is highest for those with a BMI of < 30 kg/m and lowest for those with a BMI of 30 - 40 kg/m. Inpatient complications are highest in the lower BMI population (BMI < 24 kg/m).

Conclusion: The current analysis of a nationally representative sample showed the clinical implications of BMI in patients with AMI. Patients with a BMI of 30 - 40 kg/m had more favorable LOS, inpatient complications, and in-hospital mortality when compared to those with an ideal body weight. Hence, this supports and expands on the concept of the "obesity paradox". Further studies are needed to further investigate the possible mechanism behind this.