Atypical presentations of myocardial infarction in patients with diabetes mellitus: diagnostic challenges and clinical outcomes; a systematic review

Background: Diabetes mellitus complicates recognition of myocardial infarction through heterogeneous symptoms, comorbid illness, and delayed presentation. The relationship between diabetes and absence of chest pain differs between populations. This review examined presenting symptoms, diagnostic challenges, and associated clinical outcomes. Methods: we include ten articles, covering symptom comparisons, care seeking, diagnostic recognition, and prognosis. Eligible studies concerned adults with myocardial infarction or relevant acute coronary syndrome populations and publication through May 2026. Quantitative associations and qualitative findings were examined separately without statistical pooling. Results: Large registries associated diabetes with presentation without chest pain, although Swedish investigations reported similar frequencies of typical symptoms after adjustment. Breathlessness and fatigue featured prominently in several cohorts, with inconsistent differences across individual symptoms. A Swedish multicentre study reported median delays to first medical contact of 144 minutes with diabetes and 75 minutes without diabetes. In the Korean registry, two-year mortality among patients with diabetes was 29.5% with atypical presentation versus 11.4% with typical presentation. Broader coronary syndrome cohorts linked absent chest pain to missed initial recognition and less frequent evidence-based treatment. Definitions, adjustment strategies, overlapping registry populations, and observational designs limited causal interpretation. Conclusion: Diabetes-associated myocardial infarction presents in a broad symptom spectrum. Chest pain remains common, while its absence identifies a diagnostic vulnerability. Fast electrocardiography, contextual troponin interpretation, and symptom education warrant clinical attention.