NRS-2002 components, nutritional score and severity of disease score, and their association with hospital length of stay and mortality

BACKGROUND Malnutrition is a substantial issue in hospitals, leading to prolonged length of hospital stay, increased perioperative morbidity and increased mortality. There are several validated screening tools for malnutrition, one of which is the Nutritional Risk Screening 2002 (NRS). It screens patients based on recent weight loss, reduction of recent food intake, body mass index (BMI), severity of disease and age. Higher NRS scores have been shown to be negatively associated with patients’ outcomes such as increased morbidity and mortality. OBJECTIVES The aim of the study was to evaluate how the two NRS components Nutritional Score (NS) and Severity of Disease Score (SDS) are associated with patients’ length of hospital stay and mortality. METHODS All patients admitted to the medical department of a large community hospital in Switzerland were screened for malnutrition using the nutrition screening NRS during the years 2014 to 2017. Data on patients’ NRS, primary diagnosis, number of secondary diagnoses, mortality, length of stay (LOS), discharge, sex and age were collected. The association between the NRS components and LOS/mortality was estimated using a linear mixed-effects regression model and a logistic regression model, respectively, with adjustment for confounders (age, sex, comorbidity, diagnosis group, mode of discharge and year of hospitalisation). RESULTS The evaluation of the outcomes of 21,855 hospitalisations demonstrated that the NS was associated with an increment in the LOS of 5.5–12.3% per score point, depending on the diagnosis group. An increase in the SDS by one point was associated with an increase in the LOS of 2.2–11.3%. The odds for all-cause in-hospital mortality were increased by 44.1% (95% confidence interval [CI] 33.7–55.2%) per point in the NS, and by 73% (95% CI 57.5–90.1%) per point in the SDS. CONCLUSIONS Increases in both components of the NRS are associated with longer LOS. The NS has a slightly stronger impact on LOS compared to the SDS and its effect is dependent on the patient’s diagnosis group. Increases in the SDS are linked to a higher mortality than increases in the NS.