To estimate the association between municipal multidimensional poverty (MMDP) and the risk of a first hospitalised acute myocardial infarction (AMI) among users of the Chilean public health system, and to examine whether this association differs by sex.

Multilevel analysis of a retrospective cohort study.

Primary level of care across 138 municipalities in Chile.

A total of 137,162 individuals aged ≥45 years were included, comprising 83,598 women and 53,564 men, all enrolled in the cardiovascular health programme of the Chilean public health system due to the presence of cardiovascular risk factors such as hypertension, type 2 diabetes, dyslipidaemia or tobacco use. Individuals with a prior history of AMI were excluded. Participants were clustered by municipality and followed from 1 January 2015 to 30 April 2019. Sociodemographic and clinical data at the individual level were obtained from electronic health records and linked to municipal-level poverty indicators from the National Socioeconomic Characterization Survey.

The primary outcome was the time to first hospitalised AMI . Cox proportional hazard models with a shared frailty term were used to assess the association between MMDP (defined as being in the upper quartile of the index) and AMI incidence. Models were adjusted for individual sociodemographic characteristics, behavioural risk factors (eg, smoking, diet and physical activity), and biological conditions (eg, hypertension, type 2 diabetes and dyslipidaemia). Sex-stratified analyses were conducted to explore potential differences in the association.

MMDP was significantly associated with an increased risk of AMI (HR 1.32, 95% CI 1.06 to 1.64) after adjustment for individual-level risk factors. In stratified models, the association remained significant among women (HR 1.30, 95% CI 1.01 to 1.68), but not among men (HR 1.10, 95% CI 0.93 to 1.31).

Residing in municipalities with high levels of multidimensional poverty is associated with an increased risk of AMI among individuals with cardiovascular risk factors, particularly women. These findings underscore the need for intersectoral policies to address the structural determinants of cardiovascular health.