Trends, consequences and management of hospital malnutrition in Switzerland- Findings from Swiss hospital discharge database, 2012-2022

• Swiss hospital malnutrition (trends, outcomes and management) was examined. • Hospital discharge data (>12M cases, 2012–2022) was retrospectively analysed • Malnutrition rose sixfold and was linked to poorer clinical outcomes. • Dietetic care was underutilized yet could improve in-hospital survival • Systematic screening, accurate coding and timely nutrition support could benefit diverse health systems Hospital malnutrition remains a major, yet under-recognized public health problem associated with adverse clinical outcomes. In Switzerland, national level evidence on its epidemiology and management is limited to data up till 2014. To examine recent nationwide temporal trends, demographic and clinical determinants, clinical consequences, and management practices of hospital malnutrition in Switzerland between 2012 and 2022. A retrospective analysis of the Swiss hospital discharge database (2012-2022), consisting of 12,195,344 adult hospitalizations. Multivariable logistic regression assessed available demographic and clinical factors, outcomes and management indicators associated with malnutrition. The prevalence of documented hospital malnutrition represented nearly six-fold rise in the studied ten-year period from 1.40% in 2012 to 8.14% in 2022. Older (>90 years) age (OR 9.62 95%CI(9.37-9.88)), female sex (1.26 (1.25-1.27)), higher comorbidity burden (Charlson’s comorbidity Index CCI >8, OR 6.73 (6.68-6.79)) and emergency admission (OR 1.47 (1.46-1.48)) were associated with malnutrition. Malnutrition was significantly associated with greater odds of ICU admission (OR 1.70 (1.68-1.71)), in-hospital mortality (OR 1.37 (1.35-1.39)), and prolonged (>5 days) hospital stay (OR 8.07 (8.00-8.14). Among malnourished hospitalizations, 61.9% received dietetic consultation. Dietetic consultation could attenuate the association of malnutrition diagnosis and in hospital mortality (unmatched sample: 0.86 (0.84-0.88), p<0.001 vs propensity matched sample: 0.81 (0.65 -1.02), p>0.05) but not the ICU admission and long hospital stay. Hospital malnutrition is increasingly documented in Switzerland and associated with worse in-hospital outcomes. Malnutrition management coverage remains suboptimal despite its potential benefits.