Synergistic effects of underweight and dementia on in-hospital mortality during acute myocardial infarction.

AIMS: Although the impact of underweight and dementia on mortality is clear, no large study has examined the synergistic impact of underweight and dementia on acute myocardial infarction (AMI) in real-world settings. Therefore, this study aimed to investigate the synergistic effects of underweight and dementia on in-hospital mortality in AMI patients using a nationwide administrative database.

METHODS AND

RESULTS

This nationwide retrospective cohort study was performed using the Japanese nationwide administrative data (Japanese Registry of All Cardiac and Vascular Diseases-Diagnosis Procedure Combination) of 474 979 AMI patients between April 2012 and March 2021. Of these patients, 424 500 with AMI were divided into four groups according to body mass index (<18.5 kg/m² or ≥18.5 kg/m²) and dementia status (presence or absence). We investigated the association of underweight and dementia with in-hospital mortality. In-hospital mortality was highest in the underweight/dementia group (17.5%), followed by the non-underweight/dementia group (13.2%), the underweight/non-dementia group (11.6%), and lowest in the non-underweight/non-dementia group (5.0%). Multilevel mixed-effects logistic regression analysis with multiple imputation and complete cases showed underweight and dementia to be associated alone and in combination with an increased risk of in-hospital mortality. In the subgroup analysis of age categories (<75 years vs. ≥75 years), the synergistic effects of underweight and dementia on in-hospital mortality for AMI were greater for those <75 years of age.

CONCLUSION

This nationwide study suggested that the coexistence of underweight and dementia significantly increases the risk of in-hospital mortality in AMI patients and especially younger patients. Early detection and management of both conditions may be crucial for improving survival in this population.