Background: Many nutrition risk screening tools include low body mass index (BMI). It remains uncertain whether it affects the validity of these tools in patients with overweight or obesity. We aimed to determine the frequency of malnutrition risk and evaluate its association with hospital length of stay in hospitalized adults according to BMI classification.
Methods: Secondary analysis involving inpatients with BMI ≥ 18.5 kg/m2. Malnutrition risk was assessed using the Nutritional Risk Screening 2002 (NRS-2002), Malnutrition Screening Tool (MST), Malnutrition Universal Screening Tool, Short Nutritional Assessment Questionnaire, and Nutritional Risk in Emergency-2017. Length of hospital stay, in-hospital mortality, readmission, and mortality within 6 months postdischarge were considered as outcomes.
Results: Among the 582 patients analyzed, the malnutrition risk ranged from 34.5% to 49.7% in patients with normal weight (n = 171), 20.8% to 33.9% in patients with overweight (n = 221), and 5.3% to 22.1% in patients with obesity (n = 190). Malnutrition risk by the NRS-2002 was associated with prolonged hospital stay, regardless of BMI category, and with 6-month hospital readmission in normal weight and those with obesity. The MST was associated with prolonged hospital stay, mortality, and hospital readmission in 6 months in normal-weight patients and with the first two outcomes in patients with overweight. No tool was associated with in-hospital death.
Conclusion: The prognostic value of nutrition risk screening tools varies according to BMI: the MST appears to be more appropriate for normal-weight and overweight patients, whereas the NRS-2002 may be more suitable for patients with obesity.
Keywords: length of stay; mortality; nutrition risk screening; obesity; overweight.
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