Among 7,171 acute coronary syndrome (ACS) patients across 14 Brazilian states (2020–2024), women faced systematically lower diagnostic certainty: after multivariable adjustment, their chest pain was 51–60% more likely to be classified as only "probably" or "possibly" ischemic rather than "definitely" ischemic (adjusted OR 1.51 and 1.60, respectively). Women were also significantly less likely to receive STEMI or NSTEMI diagnoses versus unstable angina (OR 0.59 and 0.74). Notably, the raw 1.53-minute door-to-ECG delay for women vanished after adjustment, and in-hospital mortality did not differ by sex.
These findings land squarely within a well-documented global pattern: women's ACS symptoms — more frequently atypical, including fatigue, nausea, and jaw pain — are routinely under-recognized by clinicians trained on male-dominant trial data. The diagnostic ambiguity captured here is clinically consequential because under-triaged ACS accelerates time-to-reperfusion delays that drive long-term cardiac damage and mortality. The private-network setting limits generalizability to Brazil's broader public health system, where resource constraints likely amplify disparities further. The retrospective design and reliance on registry data introduce unmeasured confounding risk, though E-value sensitivity analyses were appropriately deployed. This is a preprint not yet peer-reviewed, and conclusions should be treated as preliminary. Still, for a cohort this size, the finding represents confirmatory, not incremental, evidence — the persistent diagnostic uncertainty assigned to women demands sex-specific triage protocols and clinician re-education as urgent public health priorities.