Background: Obesity is considered a hazard factor for ischemic heart disease (IHD). However, it has been proposed that obese people may have a good prognosis after cardiac events, a phenomenon identified as the "obesity paradox". Objective: The aim of the present study was to examine the effect of body mass index (BMI) on clinical manifestations and outcomes following acute myocardial infarction (AMI).
Patients and methods: A retrospective, single center research was conducted at KAMC, Makkah during 2015-2020. AMI cases were allocated into three groups; Group 1 included non-obese (BMI<25) patients, Group 2 included overweight (25≥BMI<30) and Group 3 included obese (BMI≥30). Results: A total of 3018 AMI cases were enrolled in our study, of whom 834 (28%) patients were obese. Obese cases came with AMI at a younger age than overweight and non-obese ones respectively (P<0.001). Overweight and obese groups were more diabetics, hypertensive, and dyslipidemic. Contrast volume used during coronary angiography (CAG) was much elevated in obese patients than other groups (P<0.001). Overweight and obese patient groups were more in need for thrombus aspiration during CAG than non-obese (40, 38 %, and 22% respectively, P<0.001), and tirofiban use post-procedure (46%, 31%, and 24% respectively, P=0.008) in comparison to the non-obese patient group. Obese patients were less common to have multivessel disease compared to overweight and non-obese groups (24%, 43%, and 33%, respectively, P=0.01). Post-MI ejection fraction has a tendency to be much higher in obese and overweight patients in comparison to non-obese group. Conclusion: Obese patients presented with AMI at a younger age and consequently less common to have multivessel disease.