Elsevier

Nutrition

Volume 31, Issues 11–12, November–December 2015, Pages 1385-1393
Nutrition

Applied nutritional investigation
Association of nutritional risk and adverse medical outcomes across different medical inpatient populations

https://doi.org/10.1016/j.nut.2015.06.007Get rights and content

Highlights

  • Nutritional risk is substantial in acutely ill medical inpatients, with almost 30% of this population being at risk for malnutrition.

  • Nutritional risk is associated with adverse medical and functional outcomes with regard to mortality, hospital length of stay, impairments in activities of daily living and quality of life, and unplanned hospital readmissions.

  • Randomized trials are currently recruiting to evaluate the benefit of nutritional interventions such as counseling and therapy.

Abstract

Objective

The aim of this study was to examine the prevalence of nutritional risk and its association with multiple adverse clinical outcomes in a large cohort of acutely ill medical inpatients from a Swiss tertiary care hospital.

Methods

We prospectively followed consecutive adult medical inpatients for 30 d. Multivariate regression models were used to investigate the association of the initial Nutritional Risk Score (NRS 2002) with mortality, impairment in activities of daily living (Barthel Index <95 points), hospital length of stay, hospital readmission rates, and quality of life (QoL; adapted from EQ5 D); all parameters were measured at 30 d.

Results

Of 3186 patients (mean age 71 y, 44.7% women), 887 (27.8%) were at risk for malnutrition with an NRS ≥3 points. We found strong associations (odds ratio/hazard ratio [OR/HR], 95% confidence interval [CI]) between nutritional risk and mortality (OR/HR, 7.82; 95% CI, 6.04–10.12), impaired Barthel Index (OR/HR, 2.56; 95% CI, 2.12–3.09), time to hospital discharge (OR/HR, 0.48; 95% CI, 0.43–0.52), hospital readmission (OR/HR, 1.46; 95% CI, 1.08–1.97), and all five dimensions of QoL measures. Associations remained significant after adjustment for sociodemographic characteristics, comorbidities, and medical diagnoses. Results were robust in subgroup analysis with evidence of effect modification (P for interaction < 0.05) based on age and main diagnosis groups.

Conclusion

Nutritional risk is significant in acutely ill medical inpatients and is associated with increased medical resource use, adverse clinical outcomes, and impairments in functional ability and QoL. Randomized trials are needed to evaluate evidence-based preventive and treatment strategies focusing on nutritional factors to improve outcomes in these high-risk patients.

Introduction

The prevalence of undernutrition is substantial and may vary significantly across different patient populations. Based on the 2010 nutrition day survey, 32% of hospitalized patients in the Western hemisphere are at risk for malnutrition [1]. Different instruments have been proposed to screen for undernutrition. Among them, the Nutritional Risk Screening (NRS 2002) method is most widely used in European countries including Switzerland [2]. The premise of the NRS 2002 was that the indications for nutritional support should depend on two factors: the severity of impaired nutritional status and the increase in nutritional requirements resulting from disease (stress metabolism). For this reason, the NRS 2002 includes both a measure of current potential undernutrition and a measure of disease severity. Additionally, older age is considered a risk factor. Based on a retrospective analysis of 128 randomized controlled trials (RCTs) against which this method was validated, it was determined that an NRS score ≥3 may help to identify patients who would benefit from nutritional support [2]. In fact, the likelihood ratio for a positive effect at cutoffs of 3 and 4 NRS points were 1.7 and 5.

An important limitation of the initial study was that most of the included trials were surgical trials and none included the acutely ill medical inpatient population outside the intensive care unit [2]. A subsequent prospective, controlled trial with 212 hospitalized patients did not show significant effects of nutritional therapy on mortality, hospital length of stay (LOS), or quality of life (QoL), although the negative findings may be the result of a type II error (low power) [3]. This being the case, uncertainty about the potential of the NRS 2002 to identify patients who will or will not benefit from nutritional therapy in the medical inpatient setting persists along with the question of which patient population shows the highest benefit (i.e., cancer patients, infectious disease patients) [4].

Several studies have found associations of nutritional risk and adverse clinical outcome. The EuroOOPS study prospectively collected data in 26 hospital departments in different countries and found high associations of nutritional risk and complications, mortality, and LOS [5]. The aim of this study was to expand these findings and specifically examine the prevalence of nutritional risk and its association across different objective (e.g., mortality, rehospitalization) and subjective (e.g., QoL) adverse clinical outcome measures in a large and well-characterized cohort of acutely ill medical inpatients from a Swiss tertiary care hospital. We specifically asked whether associations between nutritional risk and adverse outcomes would vary across different medical diagnosis groups and after multivariable adjustment in regression models. Such an analysis may help to depict patient populations where nutritional interventions are most promising for inclusion in interventional trials.

Section snippets

Study design

In this observational cohort study, we included consecutive medical inpatients treated between March 2013 and February 2014 at a Swiss tertiary care hospital. Given that this was an observational quality control study, the Institutional Review Board (IRB) of the Canton of Aargau approved the study and waived the need for informed consent (EK 2012/059). The study was registered at the ClinicalTrials.gov registration website (NCT01768494). All authors had complete access to all the study data,

Patient population

Overall, we assessed NRS 2002 in 3186 patients. The median age was 71 y (IQR, 58 and 80) and 1423 (44.7%) of the patients were women. In all, 887 (27.8%) patients were nutritionally at risk with an NRS score of 3 points (460, 14.4%) or >3 points (427, 13.4%). Patients nutritionally at risk were older (68 y versus 75 and 74 y; P < 0.001) and less frequently discharged home (75.4% versus 54.6% and 41.9%; P < 0.001). Laboratory findings in patients nutritionally at risk showed lower serum albumin

Discussion

The main findings of this study are threefold. First, we found a high prevalence of malnutrition risk as assessed with the NRS 2002 screening system of almost 30% in the acutely ill medical inpatient population. Our data on the prevalence of risk for malnutrition derived using the NRS 2002 screening system are in line with the findings of studies from Switzerland [8], Europe [9], [10], and the United States [11], despite the use of different undernutrition screening tools in those studies.

Conclusion

Nutritional risk in acutely ill medical inpatients is substantial and associated with increased resource use, adverse medical outcomes, and impairments in functional ability and QoL. Because undernutrition often remains unrecognized, the challenge lies in proactively recognizing patients nutritionally at risk and in implementing effective nutritional management strategies to optimize clinical outcomes. Randomized trials are needed to evaluate the effectiveness of evidence-based preventive and

Acknowledgment

The authors acknowledge the local physicians, nursing staff, and patients who participated in this study. They acknowledge the staff of the emergency room, medical clinics, and central laboratories of the Kantonsspital Aarau for their helpful assistance and technical support while the study was conducted.

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This study was supported in part by the Swiss National Science Foundation (SNSF Professorship, PP00 P3_150531/1), the Swiss Academy for Medical Sciences (Schweizerische Akademie der Medizinischen Wissenschaften [SAMW]), and the Research Council of the Kantonsspital Aarau (1410.000.044). SF and CL contributed equally to this study. SF, CL, BM, and PS conceptualized and designed the study. SF, CL, MB, AK, DS, AR, SL, ZS, PK, SH, and PS contributed to the acquisition, analysis, and interpretation of the data. SF, CL, and PS drafted the manuscript, with all authors contributing to critical revision of the manuscript for important intellectual content. SF and PS performed statistical analysis. BM and PS obtained funding for the study, while RF, MD, LF, SH, and AH provided administrative, technical, or material support. The study was supervised by AH and PS. The corresponding author had full access to all the data used in the study, had final responsibility with regard to the decision to submit the manuscript for publication, and takes full responsibility for the completeness and accuracy of the data. PS, AK, and BM have received support from Thermo Fisher Scientific, Hennigsdorf, Germany. All other authors declare that they have no competing interests.

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