Temporal trends in profile of patients with acute myocardial infarction in Norway, 2013-2021

Introduction/Background Acute myocardial infarction (AMI) - classified as ST-segment elevation) or non–ST-segment elevation is- the most severe clinical expression of coronary heart disease. No previous study in Norway has explored temporal changes in AMI characteristics and severity in the context of declines in AMI incidence and improved survival. Methods Study included 74 677 incident AMI patients, aged ≥20 years, 2013–2021 in Norway registered in the Norwegian Myocardial Infarction Registry (NMIR). Information included i) age, sex, smoking status and BMI; ii) comorbidities, inc. hypertension, diabetes mellitus (DM), stroke and chronic heart failure (CHF); and iii) AMI severity indicators: resuscitation, non-invasive ventilation (NIV; CPAP or BiPAP), pulmonary oedema (PE), cardiogenic shock (CS), major ventricular rhythm disturbances [ventricular tachycardia (VT), ventricular fibrillation (VF), cardiac arrest/asystole], 2nd or 3rd -degree atrioventricular block, and pacemaker implantation. Temporal changes in each characteristic (i–iii), were assessed using Poisson regression adjusted for age and sex. Incidence rate ratios (IRRs) were used to derive average annual percent change (AAPC) with 95% CIs using (IRR−1)×100%, quantifying mean year-on-year change from 2013 to 2021. Results i) Mean age, 69.6 (13.8) years; 31.3% STEMI, 68.7% men. 30.9% were current smokers and 23% were obese. ii) The proportions of hypertension, stroke, diabetes mellitus (DM) and chronic heart failure (HF) were 44.9%, 7.1%, 17.4% and 4.2%, respectively; 16.9% had ≥2 comorbidities. iii) 3.4% of AMIs were resuscitated prior to and another 3.1%, when hospitalized for the index AMI. 7.0% received respiratory support, 15.0% experienced pulmonary oedema and 2.9% cardiogenic shock. A major rhythm disturbance and a high degree atrioventricular block were observed in 5.9% and 2.1% of patients, respectively. Time trends in patient characteristics The proportion of current smokers declined (NSTEMI: -2.2%; STEMI: -1.6%) while the proportion of obese patients increased (NSTEMI: +5.5%; STEMI: +5.0%). We observed declines in stroke (NSTEMI: -2.7%; STEMI: -3.1%) and CHF (NSTEMI: -3.0%) and increases in DM (NSTEMI: + 1.9%; STEMI: 3.4%) and multimorbidity (in STEMI only: +1.5%) prevalence We observed declines for most severity indicators in NSTEMI patients: resuscitation prior to (-2.8%) and during AMI hospitalization (-6.1%), PE (-5.5%), CS (-9.5%) and AV-block (-4.6%). Most indicators did not change in STEMI patients, and proportion of patients requiring resuscitation during AMI hospitalization and those suffering PE even increased (both by +2.4%) Conclusion Indicators of clinical severity decreased among NSTEMI patients, whereas changed little and even worsened for resuscitation during hospitalization and pulmonary oedema among STEMI, underscoring divergent temporal patterns that may require subtype-specific prevention and in-hospital management strategies.