Unintended Weight Loss in Older Adults

UWL: Screening and Assessment Methods (2009)

Citation:

Burden ST, Bodey S, Bradburn YJ, Murdoch S, Thompson AL, Sim JM, Sowerbutts AM. Validation of a nutrition screening tool: testing the reliability and validity. J Hum Nutr Diet 2001;14(4):269-275.

PubMed ID: 11493385
 
Study Design:
Cross-sectional study
Class:
D - Click here for explanation of classification scheme.
Quality Rating:
Neutral NEUTRAL: See Quality Criteria Checklist below.
Research Purpose:

The aim of this study was to validate a nutrition screening tool for use in South Manchester University Hospitals Trust. The objectives were to determine inter-observer error to evaluate reproducibility, and to assess the degree to which the tool identifies malnourished patients and those at risk of malnutrition in the real-world environment of a hospital ward.

Inclusion Criteria:

None specifically mentioned.

Exclusion Criteria:
  • Unconscious
  • Bed-bound
  • Unable to be weighed
  • Confused.
Description of Study Protocol:

Recruitment

Two wards within each directorate were included, eight wards in total.  A sample of 100 patients was selected from medical, surgical and elderly care wards.

Design

Cross-sectional study.

Statistical Analysis

  • Frequency distribution and cross tabulations were run to explore the data set
  • Fisher's exact test for two-sided significance was used for the nominal data
  • Results were compared for inter-observer error to determine whether the screening tool was reproducible with different observers.
Data Collection Summary:

Timing of Measurements

To test the reliability of the screening tool, nurses and dietitians completed the screening tool on the same patient. Nurses screened all patients within the first 24 hours of admission, and the dietitian completed another screening tool independently within 48 hours of admission. 

Dependent Variables

Identification of malnutrition at ward level.

Independent Variables

  • Screening tool with four common markers of nutritional status: body mass index (BMI), mid-upper arm circumference (MUAC), percentage weight loss and energy intake calculated from the patient's first full day in the hospital and expressed as a percentage of their estimated average requirements (EAR)
  • Patients were considered malnourished if they fell into one of the following categories: 
    • BMI less than 20
    • MUAC less than the15th percentile
    • Dietary intake less than 25% of the patient's EAR
    • Weight loss more than 10%.
Description of Actual Data Sample:

Initial N: 100 patients

Attrition (final N): 100 patients (67 women, 33 men)

Age: Mean age, 63 years; range, 25 to 93 years

Ethnicity: Not mentioned

Location: United Kingdom.

 

Summary of Results:

 

Variables

MUAC<15th percentile EAR intake<25%

Weight loss>10%

BMI<20

Sensitivity

82 59 35  59 

Specificity

86

86

86

92

Other Findings

The screening tool identified 17% of patients as malnourished (scores more than 15), 50% at moderate risk of malnutrition (scores 10 to 14) and 33% at minimal risk (scores 7 to 9).

There was a 95% level of agreement between nurses and dietitians within ±3%.

The screening tool had a sensitivity level of 78% and a specificity of 52% when compared with all patients who had one or more markers indicating malnutrition.

This association was found to be statistically significant (P<0.005). 

Author Conclusion:

The screening tool is reliable when completed by different observers and is valid for wide scale nutritional assessment. The screening tool identifies an acceptable number of patients who are malnourished but overestimates patients at moderate risk.

Funding Source:
University/Hospital: Department of Nutrition and Dietetics, Withington Hospital, Nell Lane, Didsbury, Manchester M20 2LR, UK
Other: Not reported
Reviewer Comments:

Relatively small sample size. Authors note that inclusion and exclusion criteria were used that introduced unavoidable bias into the sampling procedure.

Quality Criteria Checklist: Primary Research
Relevance Questions
  1. Would implementing the studied intervention or procedure (if found successful) result in improved outcomes for the patients/clients/population group? (Not Applicable for some epidemiological studies) Yes
  2. Did the authors study an outcome (dependent variable) or topic that the patients/clients/population group would care about? Yes
  3. Is the focus of the intervention or procedure (independent variable) or topic of study a common issue of concern to dieteticspractice? Yes
  4. Is the intervention or procedure feasible? (NA for some epidemiological studies) Yes
 
Validity Questions
1. Was the research question clearly stated? Yes
  1.1. Was (were) the specific intervention(s) or procedure(s) [independent variable(s)] identified? Yes
  1.2. Was (were) the outcome(s) [dependent variable(s)] clearly indicated? Yes
  1.3. Were the target population and setting specified? Yes
2. Was the selection of study subjects/patients free from bias? ???
  2.1. Were inclusion/exclusion criteria specified (e.g., risk, point in disease progression, diagnostic or prognosis criteria), and with sufficient detail and without omitting criteria critical to the study? Yes
  2.2. Were criteria applied equally to all study groups? N/A
  2.3. Were health, demographics, and other characteristics of subjects described? Yes
  2.4. Were the subjects/patients a representative sample of the relevant population? ???
3. Were study groups comparable? N/A
  3.1. Was the method of assigning subjects/patients to groups described and unbiased? (Method of randomization identified if RCT) N/A
  3.2. Were distribution of disease status, prognostic factors, and other factors (e.g., demographics) similar across study groups at baseline? N/A
  3.3. Were concurrent controls or comparisons used? (Concurrent preferred over historical control or comparison groups.) N/A
  3.4. If cohort study or cross-sectional study, were groups comparable on important confounding factors and/or were preexisting differences accounted for by using appropriate adjustments in statistical analysis? N/A
  3.5. If case control study, were potential confounding factors comparable for cases and controls? (If case series or trial with subjects serving as own control, this criterion is not applicable.) N/A
  3.6. If diagnostic test, was there an independent blind comparison with an appropriate reference standard (e.g., "gold standard")? N/A
4. Was method of handling withdrawals described? Yes
  4.1. Were follow-up methods described and the same for all groups? Yes
  4.2. Was the number, characteristics of withdrawals (i.e., dropouts, lost to follow up, attrition rate) and/or response rate (cross-sectional studies) described for each group? (Follow up goal for a strong study is 80%.) Yes
  4.3. Were all enrolled subjects/patients (in the original sample) accounted for? Yes
  4.4. Were reasons for withdrawals similar across groups? N/A
  4.5. If diagnostic test, was decision to perform reference test not dependent on results of test under study? N/A
5. Was blinding used to prevent introduction of bias? ???
  5.1. In intervention study, were subjects, clinicians/practitioners, and investigators blinded to treatment group, as appropriate? N/A
  5.2. Were data collectors blinded for outcomes assessment? (If outcome is measured using an objective test, such as a lab value, this criterion is assumed to be met.) ???
  5.3. In cohort study or cross-sectional study, were measurements of outcomes and risk factors blinded? ???
  5.4. In case control study, was case definition explicit and case ascertainment not influenced by exposure status? N/A
  5.5. In diagnostic study, were test results blinded to patient history and other test results? N/A
6. Were intervention/therapeutic regimens/exposure factor or procedure and any comparison(s) described in detail? Were interveningfactors described? Yes
  6.1. In RCT or other intervention trial, were protocols described for all regimens studied? N/A
  6.2. In observational study, were interventions, study settings, and clinicians/provider described? Yes
  6.3. Was the intensity and duration of the intervention or exposure factor sufficient to produce a meaningful effect? N/A
  6.4. Was the amount of exposure and, if relevant, subject/patient compliance measured? N/A
  6.5. Were co-interventions (e.g., ancillary treatments, other therapies) described? N/A
  6.6. Were extra or unplanned treatments described? N/A
  6.7. Was the information for 6.4, 6.5, and 6.6 assessed the same way for all groups? N/A
  6.8. In diagnostic study, were details of test administration and replication sufficient? N/A
7. Were outcomes clearly defined and the measurements valid and reliable? Yes
  7.1. Were primary and secondary endpoints described and relevant to the question? N/A
  7.2. Were nutrition measures appropriate to question and outcomes of concern? Yes
  7.3. Was the period of follow-up long enough for important outcome(s) to occur? N/A
  7.4. Were the observations and measurements based on standard, valid, and reliable data collection instruments/tests/procedures? Yes
  7.5. Was the measurement of effect at an appropriate level of precision? Yes
  7.6. Were other factors accounted for (measured) that could affect outcomes? ???
  7.7. Were the measurements conducted consistently across groups? N/A
8. Was the statistical analysis appropriate for the study design and type of outcome indicators? Yes
  8.1. Were statistical analyses adequately described and the results reported appropriately? Yes
  8.2. Were correct statistical tests used and assumptions of test not violated? Yes
  8.3. Were statistics reported with levels of significance and/or confidence intervals? Yes
  8.4. Was "intent to treat" analysis of outcomes done (and as appropriate, was there an analysis of outcomes for those maximally exposed or a dose-response analysis)? N/A
  8.5. Were adequate adjustments made for effects of confounding factors that might have affected the outcomes (e.g., multivariate analyses)? Yes
  8.6. Was clinical significance as well as statistical significance reported? Yes
  8.7. If negative findings, was a power calculation reported to address type 2 error? N/A
9. Are conclusions supported by results with biases and limitations taken into consideration? Yes
  9.1. Is there a discussion of findings? Yes
  9.2. Are biases and study limitations identified and discussed? Yes
10. Is bias due to study's funding or sponsorship unlikely? Yes
  10.1. Were sources of funding and investigators' affiliations described? No
  10.2. Was the study free from apparent conflict of interest? Yes