Background: Malnutrition is a common problem in patients admitted to and staying in hospital wards, occurring in 30–50% of patients. Malnutrition is also often associated with longer hospital stays, more complications and higher treatment costs. The purpose of the study is to assess the effectiveness of the NRS-2002 (Nutrition Risk Screening) and SNAQ (Simplified Nutritional Appetite Questionnaire) in checking the risk of malnutrition and significant weight loss in patients in selected hospital wards.

Methods: The analysis included 100 patients from hospital wards (nephrology and geriatric). The differences between the NRS-2002 carried out at admission to the hospital and the repeated NRS-2002 during hospitalisation, the prevalence of malnutrition and the risk of losing 5% of body weight over 6 months depending on the ward were assessed.

Results: Out of all participants in the study, 51 patients (51%) had the NRS 2002 result indicating malnutrition. Also, 51 patients had a SNAQ score ≤ 14 indicating a significant risk of losing at least 5% of their body weight within the next 6 months. The analysis of the correlation between the NRS-2002 and the SNAQ showed a negative relationship (R = (–0.2425); p = 0.017). Malnourished patients are older (p < 0.0001), have a lower body weight (p = 0.002) and lower body mass index (BMI) (p = 0.05), patients with risk of malnutrition occurred almost equally in both wards (25 patients in geriatric vs. 26 patients in nephrology). Malnourished patients may also be more likely to have lower food intake (p = 0.005).

Conclusion: Malnutrition is very common in hospitalized patients with an emphasis on geriatric and nephrology patients. Correlation analysis showed a correlation of NRS with age and a negative correlation of SNAQ with CRP level. Unfortunately, on admission to hospital, the nutritional status is underestimated and fewer patients than expected are at risk of malnutrition. Correct identification of malnourished patients and those at risk of significant weight loss is the basis for appropriate treatment and should be carried out by a member of the nutrition team.