Epidemiology and clinical outcomes of malnutrition in hospital admissions for acute myocardial infarction in Switzerland, 1998–2022

Background Malnutrition is frequent but under-recognized condition among the acute myocardial infarction (AMI) patients. Population-level evidence on temporal trends and its association with in-hospital outcomes remains limited. Methods We performed a nationwide retrospective analysis of hospitalizations for AMI hospitalizations using the Swiss hospital discharge data from 1998 to 2022. Malnutrition was defined in two ways; as ICD-10[1] codes E40 to E46 (M1), and ICD-10 codes plus receipt of enteral (CHOP[2] code beginning with 96.6) or parenteral (code 99.15) nutrition among hospitalizations without a malnutrition code (M2). Cardiac procedures were assessed by the CHOP codes beginning with 36.1, 00.66, 36.9 or 35. Bivariate and multivariable analyses assessed associations of clinical outcomes (Intensive Care Unit (ICU) admission, prolonged (>5 days) Length of Stay (LoS) and in-hospital mortality) with malnutrition and nutritional interventions (dietetic consultation (DC) and, (par)enteral nutrition support (PN and EN)). Results Among 351,369 hospitalizations for AMI (30.3% female), malnutrition according to definition M1 was identified in 1.3%. The prevalence increased significantly from 0.0% in 1998 to 3.6% in 2022 (p for trend <0.001). After multivariable adjustment, malnutrition was associated with higher odds of ICU admission (OR, 95% CI 1.21, 1.13–1.30) and prolonged LoS (12.50, 11.18–13.97), but not with in-hospital mortality (0.90,0.80–1.02). Using definition M2, malnutrition was associated with increased odds of ICU admission (2.93, 2.79–3.08), prolonged length of stay (8.39, 7.80–9.03), and in-hospital mortality (2.87,2.68–3.08). A rising temporal trend was observed for the percentage of AMI patients with a malnutrition diagnosis (any code) receiving dietetic consultation, from 0.0% in 1998 to 52.9% in 2022. Overall, DC was provided to nearly half (55%) of the AMI patients coded as malnourished. For the recipients of cardiac procedures, DC and nutrition support were associated with a higher likelihood of ICU admission (DC: 1.76, 1.55-2.00; EN: 9.71, 8.44-11.20; PN: 3.88, 2.97-5.08) and prolonged LoS (DC: 10.5, 8.69-12.69; EN: 5.46, 4.82-6.19; PN: 3.79, 2.86-5.01). DC decreased the likelihood of in hospital mortality (0.43, 0.33-0.56) while EN and PN increased it (EN: 6.02, 5.37-6.74; PN: 3.64, 2.94-4.51), likely due to the already severe disease in patients requiring nutrition support. Similar findings were replicated for all AMI hospitalizations (receiving or not receiving the cardiac procedures). Conclusion Hospital malnutrition among AMI patients appears increasingly prevalent yet underestimated. Malnutrition is associated with more severe conditions and adverse clinical outcomes. The potential of dietetic consultation against in-hospital mortality underscores the need for systematic screening and intervention practices in AMI care pathways.