Nutritional Risk Screening and Clinical Outcomes in a Tertiary University Hospital: A Real-World Retrospective Cohort Study

Background & objectives: Malnutrition risk is common among hospitalized patients and is associated with adverse clinical outcomes. However, implementation of routine nutritional screening remains heterogeneous. This study assessed the distribution and implementation of Nutritional Risk Screening 2002 (NRS-2002) and examined associations between malnutrition risk and clinical outcomes in a tertiary university hospital. Methods: We conducted a retrospective cohort study using routinely collected electronic health record data from adult hospitalizations at the University of Leipzig Medical Center, Germany, between 2013 and 2023. The implementation of the NRS-2002 in 2017 enabled comparison of a main cohort with potential NRS assessment (2017-2023) and a pre-implementation comparison cohort (2013-2016). In the main cohort, hospitalizations were categorized according to screening results as no elevated malnutrition risk, NRS [≥]3 points, or positive initial screening without a documented final NRS assessment. Clinical outcomes included 30-day hospital readmission, intensive care unit (ICU) admission, mechanical ventilation, in-hospital mortality, and length of hospital stay (LOS). Associations were assessed using unadjusted and age- and sex-adjusted logistic regression. Length of hospital stay was analyzed using Gamma regression. Time to readmission was additionally assessed using Kaplan-Meier and Cox regression. Results: After data preprocessing, 178,607 hospitalizations were included in the main cohort and 52,044 in the comparison cohort. In the main cohort, 5,460 hospitalizations (3.1%) had an NRS [≥]3 points, while 21,842 (12.2%) had a positive initial screening without a documented final assessment. Patients with NRS [≥]3 points had higher rates of 30-day readmission, ICU admission, and in-hospital mortality and longer LOS than patients without elevated malnutrition risk. After adjustment for age and sex, NRS [≥]3 points remained associated with higher odds of 30-day readmission (OR 1.57, 95% CI 1.39-1.77), ICU admission (OR 1.85, 95% CI 1.63-2.11), in-hospital mortality (OR 3.62, 95% CI 2.69-4.99), and mechanical ventilation (OR 2.07, 95% CI 1.08-4.38). Hospitalizations with a positive initial screening but without a documented final assessment also showed increased odds of several adverse outcomes, including 30-day readmission and in-hospital mortality. The proportion of positive initial screenings and completion of the final NRS assessment varied substantially across clinical departments. Conclusion: Elevated malnutrition risk was associated with adverse clinical outcomes in this large real-world cohort. The substantial proportion of positive initial screenings without subsequent final assessment highlights important challenges in implementing a complete nutritional screening pathway in routine hospital care.