Date Published: January 24, 2019
Publisher: Public Library of Science
Author(s): Martin Müller, Suzan Dahdal, Mo Saffarini, Dominik Uehlinger, Spyridon Arampatzis, Wisit Cheungpasitporn.
Although chronic kidney disease (CKD) patients are particularly prone to malnutrition, systematic nutritional screening is rarely routinely performed during hospitalization. The primary aim of this study was to determine the prevalence of malnutrition (as captured by the nutritional screening score NRS) in hospitalized CKD patients and explore the impact of malnutrition on hospital mortality.
All patients admitted to the tertiary nephrology department of the University hospital of Bern Inselspital over a period of 12 months were included in this observational study. The risk for malnutrition was assessed within 24h of admission by the NRS. Demographic, clinical, and outcome data were extracted from the patient database. The primary outcome was in-hospital mortality. The secondary outcomes were length of hospitalization and hospitalization costs. Multilevel mixed-effect logistic regression model analysis was performed to determine the association of in-hospital mortality and risk of malnutrition (NRS score≥3).
We included 696 eligible hospitalizations of 489 CKD patients. Hospitalized patients had a median age of 64 years (interquartile range (IQR), 52–72), 35.6% were at risk of malnutrition (NRS≥3). After adjustment for the identified confounders (Case weight, Barthel index, and CKD stage) multivariate analysis confirmed an independent and significant association between higher in-hospital mortality with NRS≥3 [OR 2.92 (95% CI: 1.33–6.39), P<0.001]. Furthermore, in multivariate analysis the risk of malnutrition was associated with longer length of hospitalization [Geometric mean ratio: 1.8 (95% CI: 1.5–2.0), p<0.001] and with increased hospitalization costs [Geometric mean ratio: 1.7 (95% CI: 1.5–1.9), p<0.001]). Malnutrition in CKD patients, as captured by NRS>3, is highly prevalent among hospitalized CKD patient and associated with prolonged hospital stay and increased in-hospital mortality.
The prevalence of malnutrition in chronic patients is substantial and varies significantly depending on the screening instruments used for assessment. In hospitalized patients, malnutrition is observed in 20–60% and is associated with increased morbidity, mortality, and healthcare costs [1–5]. Chronic kidney disease (CKD) patients are commonly depleted of protein and energy stores and particularly prone to develop malnutrition [6, 7]. Yet, many CKD patients with a high risk of malnutrition remain undetected during hospitalization, due to the lack of standardized nutritional screening tools. Several studies have found associations between nutritional risk and adverse clinical outcome using various screening tools such as the Subjective Global Assessment (SGA) , the Malnutrition Screening Tool (MST) and the Nutrition Risk Screening 2002 (NRS) . So far, the most successfully evaluated screening tools in CKD patients are the SGA or one of its adaptations [10, 11]. The NRS combines both a measure of current potential undernutrition and a measure of disease severity and has been validated in various patient groups. It was shown to be reliable to identify hospital patients at risk of malnutrition and was therefore recommended by the European Society of Clinical Nutrition and Metabolism (ESPEN) . The NRS has equivalent sensitivity and specificity compared to the SGA, but is quicker and simpler to use, and thus requires considerably less examiner training [13, 14]. There is scant information regarding the standardized use of the NRS in tertiary nephrology wards. If malnutrition imparts added functional impairment in patients with CKD, there might be a strong rationale for screening and treating malnutrition during hospitalization in the hopes of improving functional status and outcomes.
Demographic and hospitalization characteristics are shown in Table 1. A total of 747 hospitalizations of 508 patients were admitted to the nephrology department during the 12-month study period. In total, 6.8% (n = 51) had to be excluded because of incomplete documentation (Fig 1). Thus, 696 hospitalizations of 489 patients were included in the main analysis.
Patients with CKD are particularly vulnerable to the deleterious effects of malnutrition although malnutrition often remains unrecognized . The primary aim of the study was to explore the prevalence of malnutrition among patients admitted on a tertiary nephrology ward as captured by the NRS screening tool. This observational study shows that more than one-third of hospitalised CKD patients were at risk of malnutrition. Furthermore, such patients have significantly higher in-hospital mortality, generate higher healthcare costs, and have a longer length of hospitalization.