The manifestation of obesity paradox in patients with myocardial infarction and various systolic dysfunctions: myth or reality?

Objective. To identify the relationships between obesity and prognosis in patients after myocardial infarction within three years of observation, depending on the severity of post-infarction systolic myocardial dysfunction.Material and Methods. The study design was based on a three-year follow-up retrospective analysis of patients from the register of acute coronary syndrome of Kemerovo city in 2015 (n = 1366). The main clinical outcomes, including death from all causes, recurrent myocardial infarction (RIM), cerebral stroke, hospitalization for unstable angina pectoris (UA), and decompensation of heart failure (HF), were assessed taking into account the initial values of the left ventricular (LV) ejection fraction (EF) in the groups of obese or non-obese patients who suffered from myocardial infarction. Obesity was defined based on body mass index (BMI).Results. General obesity was detected in 282 patients (32.2%) at the time of myocardial infarction. Obesity did not adversely affect myocardial infarction outcomes in the general group of patients during the three-year follow up, but it was associated, as a protective factor, with the number of hospitalizations for UA only in patients with BMI ≥35 kg/m2 . Additional stratification of patients by LV EF showed a paradox of obesity and a decrease in systolic myocardial function from 41 to 49% in the group of patients with myocardial infarction and BMI-estimated general obesity. There was a significant decrease in the all-cause mortality rate within three years of observation in the obese patients with initially severe systolic dysfunction compared with that in patients with systolic dysfunction and initial BMI of less than 30 kg/m2 .Conclusion. The presence of general obesity did not affect the development of an unfavorable outcome in the general group of patients within three years after myocardial infarction, with the exception of non-obese patients with severe systolic dysfunction who had the highest rate of total mortality. Regardless of the degree of post-infarction systolic myocardial dysfunction, obesity can be protective in regard to the development of UA in patients with a BMI greater than or equal to 35 kg/m2 .