Elsevier

Clinical Nutrition

Volume 31, Issue 3, June 2012, Pages 345-350
Clinical Nutrition

Original article
Malnutrition and its impact on cost of hospitalization, length of stay, readmission and 3-year mortality

https://doi.org/10.1016/j.clnu.2011.11.001Get rights and content

Summary

Background & aims

The confounding effect of disease on the outcomes of malnutrition using diagnosis-related groups (DRG) has never been studied in a multidisciplinary setting. This study aims to determine the prevalence of malnutrition in a tertiary hospital in Singapore and its impact on hospitalization outcomes and costs, controlling for DRG.

Methods

This prospective cohort study included a matched case control study. Subjective Global Assessment was used to assess the nutritional status on admission of 818 adults. Hospitalization outcomes over 3 years were adjusted for gender, age, ethnicity, and matched for DRG.

Results

Malnourished patients (29%) had longer hospital stays (6.9 ± 7.3 days vs. 4.6 ± 5.6 days, p < 0.001) and were more likely to be readmitted within 15 days (adjusted relative risk = 1.9, 95% CI 1.1–3.2, p = 0.025). Within a DRG, the mean difference between actual cost of hospitalization and the average cost for malnourished patients was greater than well-nourished patients (p = 0.014). Mortality was higher in malnourished patients at 1 year (34% vs. 4.1 %), 2 years (42.6% vs. 6.7%) and 3 years (48.5% vs. 9.9%); p < 0.001 for all. Overall, malnutrition was a significant predictor of mortality (adjusted hazard ratio = 4.4, 95% CI 3.3–6.0, p < 0.001).

Conclusions

Malnutrition was evident in up to one third of the inpatients and led to poor hospitalization outcomes and survival as well as increased costs of care, even after matching for DRG. Strategies to prevent and treat malnutrition in the hospital and post-discharge are needed.

Introduction

Malnutrition is prevalent in the hospital setting with 20-50% of patients identified as malnourished at admission.1, 2 Poor nutrition has been adversely associated with a range of clinical, functional and economic outcomes.1, 3, 4 Malnourished patients have been shown to have a length of hospital stay 1.5–1.7 times longer than well-nourished patients.3, 4 They have also been shown to have a three-fold increase in mortality over a 12-month period post discharge.3

The prevalence of inpatient malnutrition and its related outcomes are likely to vary with different populations and health care settings. Yet there are few studies reporting prevalence of malnutrition in Asian hospitals and these have largely focused on older adults.5, 6, 7 The true prevalence of malnutrition in a Singapore acute-care hospital setting has not been clearly established. A previous study done in a large acute-care hospital in Singapore, found the “prevalence” to be 15% using Subjective Global Assessment (SGA).8 However, this figure is likely to be an underestimate as only patients screened to be at risk of malnutrition using the Malnutrition Screening Tool9 were assessed using SGA. Furthermore, patients were selected from four discipline-specific wards and hence may not be representative of all hospital patients.

Few studies have prospectively examined the long term clinical outcomes of malnutrition3 and consideration of the confounding effect of disease or diagnosis-related groups (DRG) is rare.10 Even fewer studies have investigated mortality outcomes using data from national death registers.3 Furthermore, most studies evaluating the prognostic significance of malnutrition have focused on Caucasian populations, whilst studies in Asian populations are scarce.1, 3, 4

The aim of this study was to comprehensively determine the prevalence of malnutrition and its impact on length of hospital stay, readmission, 3-year mortality and cost of hospitalization in patients newly admitted to an acute-care tertiary hospital in Singapore, across different DRG.

Section snippets

Study participants and study design

The study participants were patients newly admitted to National University Hospital (NUH), which is a 987-bed acute tertiary hospital, with a comprehensive range of medical and surgical specialties. Its catchment includes the western region of Singapore as well as complicated clinical cases that require specialist tertiary care from all over the country. To ensure that study subjects were as representative of the institution’s patient profile as possible, consecutive patients newly admitted to

Demographics of participants

A total of 1079 patients fulfilled the inclusion criteria and were eligible to participate in the study. From these, 818 (76%) patients participated in the study, 11 declined to participate and 250 were discharged within 48 hours of admission before SGA could be completed. The demographic profiles of the participants and of the hospital population are described in Table 1. The study sample was older than the hospital population (difference = 2.6 years, CI 1.48–3.58) but there was no difference in

Discussion

This study is amongst the first to examine the impact of malnutrition on length of hospital stay, readmission, hospitalization cost and mortality in a large sample representative of patients admitted to a major Singaporean tertiary hospital. In addition, few studies have controlled for the confounding effect of diagnosis on malnutrition outcomes or used national death register data to determine mortality outcomes. After controlling for the potential confounders of age, gender, ethnicity and

Conclusions

Malnutrition is evident in up to one third of the patients admitted to a Singapore tertiary hospital and leads to substantial increases in length of hospital stay, readmission rate, mortality and hospitalization cost when compared with well-nourished patients of similar diagnosis. As such, this study provides clear evidence that the adverse outcomes of malnutrition are not just a consequence of the disease process. Given the prevalence of malnutrition and its poor short and longer term

Statement of authorship

SLL conceptualized, designed and conducted the study, interpreted the data and wrote the manuscript. KCBO, WCL and MF provided significant advice on the design of the study and assisted in writing the manuscript. YHC performed statistical analysis and interpreted the data. LD interpreted the data, provided significant advice on the design of the study and assisted in writing the manuscript. All authors have made substantial contributions and approved the final manuscript.

Conflict of interest

None of the authors had any conflict of interest related to the authorship of the submitted paper.

Acknowledgements

The recruitment phase of this study was supported by the National Healthcare Group Small Innovative Grant (NHG-SIG).

We thank Ms Tan Ai Vee (Singapore Ministry of Health), Ms Cherie Tong (National University Hospital) and Ms Serene Wong (National University Hospital) for contributing part of the data collection and Dr Merrilyn Banks (Royal Brisbane & Women’s Hospital) for her advice on DRG. We also thank Mr. Dennie Hsu from National University Hospital for his unwavering support for this study.

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