Association of body mass index, metabolic health status and clinical outcomes in acute myocardial infarction patients: a national registry-based study

Front Cardiovasc Med. 2023 Jun 26:10:1142078. doi: 10.3389/fcvm.2023.1142078. eCollection 2023.

Abstract

Introduction: Obesity is an important risk factor for acute myocardial infarction (AMI), but the interplay between metabolic health and obesity on AMI mortality has been controversial. In this study, we aimed to elucidate the risk of short- and long-term all-cause mortality by obesity and metabolic health in AMI patients using data from a multi-ethnic national AMI registry.

Methods: A total of 73,382 AMI patients from the national Singapore Myocardial Infarction Registry (SMIR) were included. These patients were classified into four groups based on the presence or absence of metabolic diseases, diabetes mellitus, hyperlipidaemia, and hypertension, and obesity: (1) metabolically-healthy-normal-weight (MHN); (2) metabolically-healthy-obese (MHO); (3) metabolically-unhealthy-normal-weight (MUN); and (4) metabolically-unhealthy-obese (MUO).

Results: MHO patients had reduced unadjusted risk of all-cause in-hospital, 30-day, 1-year, 2-year, and 5-year mortality following the initial MI event. However, after adjusting for potential confounders, the protective effect from MHO on post-AMI mortality was lost. Furthermore, there was no reduced risk of recurrent MI or stroke within 1-year from onset of AMI by the MHO status. However, the risk of 1-year mortality was higher in female and Malay AMI patients with MHO compared to MHN even after adjusting for confounders.

Conclusion: In AMI patients with or without metabolic diseases, the presence of obesity did not affect mortality. The exception to this finding were female and Malay MHO who had worse long-term AMI mortality outcomes when compared to MHN suggesting that the presence of obesity in female and Malay patients may confer worsened outcomes.

Keywords: AMI mortality; AMI prognosis; MHO paradox; acute myocardial infarction; cardiovascular risk; metabolically healthy obesity (MHO); metabolism; obesity paradox.

Grants and funding

CS was supported by the National University of Singapore Yong Loo Lin School of Medicine’s Junior Academic Fellowship Scheme, the NUHS Seed Fund (NUHSRO/2022/059/RO5+6/Seed-Mar/04) and the Singapore Ministry of Health’s National Medical Research Council under its Clinician Scientist Individual Research Grant New Investigator Grant (NMRC/CNIG21nov-0014). JK was supported by the SingHealth Medical Student Talent Development Awards (SMSTDA, Project and Travel Awards). AH was supported by Khoo Clinical Scholars Programme, Khoo Pilot Award (KP/2019/0034), Duke-NUS Medical School and National Medical Research Council (NMRC/CS_Seedfd/012/2018). DH was supported by the British Heart Foundation (CS/14/3/31002), the National Institute for Health Research University College London Hospitals Biomedical Research Centre, Duke-National University of Singapore Medical School, Singapore Ministry of Health’s National Medical Research Council under its Clinician Scientist-Senior Investigator scheme (NMRC/CSA-SI/0011/2017), Centre Grant scheme (CG21APR1006), and Collaborative Centre Grant scheme (NMRC/CG21APRC006). This article is based upon work from COST Action EU-CARDIOPROTECTION CA16225 supported by COST (European Cooperation in Science and Technology).