Care and outcomes of first-time myocardial infarction among vulnerable populations in Denmark, 2003-22: a nationwide registry-based cohort study.

Background: Mortality following a first-time myocardial infarction (MI) has declined, yet disparities in treatment and outcomes among potentially vulnerable groups remain unclear. We aimed to examine trends in treatment and mortality among first-time MI patients from 2003 to 2022 across eight potentially vulnerable subgroups in Denmark. Methods: Using Danish registries, patients with a first-time MI between 2003 and 2022 were identified and divided into five-year calendar groups and eight subgroups ('age ≥80', 'low income', 'female', 'frail', 'non-Western immigrant', 'history of mental illness', 'living alone', and 'living in a rural area'). Temporal trends in treatment initiation and mortality were assessed using Kaplan Meier estimates and multivariable Cox regression. Findings: Among 118,674 patients included, guideline-recommended therapy initiation increased over time, though gaps persisted (e.g. statin initiation in 2018-2022: 77.0% (2241/2911) among frail patients vs. 90.2% (19,986/22,157) among their counterparts). Crude and adjusted mortality rates declined for all subgroups over time, yet gaps persisted. Mortality remained highest among frail patients (5-year mortality risk of 48.7% [95% CI 46.5-50.9] in 2018-2022) and those aged ≥80 years (56.5% [95% CI 54.5-58.5]), no mortality difference was observed between patients living in rural areas and their counterparts (21.6% [95% CI 20.6-22.6] vs. 21.3% [95% CI 19.8-20.6] in 2018-2022), and non-Western immigrants exhibited lower mortality than their counterparts (8.8% [95% CI 7.0-10.6] vs. 21.3% [95% CI 20.7-22.0] in 2018-2022). Interpretation: Despite improvements from 2003 to 2022, persistent disparities underscore ongoing inequities and the need for targeted efforts to promote equity. Funding: None.