UWL: Association With Outcomes (2009)

Study Design:
- Click here for explanation of classification scheme.
Quality Rating:
Research Purpose:
  • To determine whether an association exists between mortality risk and either the six-month average intra-resident monthly variation in recorded weight measurements or the relative change in weight during any single time interval among a national sample of nutritionally at-risk elderly nursing home residents
  • To determine what baseline resident characteristics were associated with greater six-month average intra-resident monthly variation in weight.
Inclusion Criteria:
  • Capable of oral feeding at the time of the initial review
  • Had a nutritional problem identified within the previous three months that placed them at nutritional risk
  • Nutritional risk was defined as weight loss, poor appetite or both, according to one of the following: MDS documentation of poor appetite, chart documentation of poor appetite prompting dietary consultation, MDS documentation of a weight loss of 5% or more within a one-month period or chart documentation of weight loss prompting dietary consultation
  • Had to remain in an intermediate or skilled nursing home bed for at least two months.
Exclusion Criteria:

Excluded if not included above.

Description of Study Protocol:


All participants were recruited as part of the GAIN (Geriatric Anorexia Nutrition) Registry. The Registry was developed by an advisory panel composed of thought leaders in the fields of geriatric nutrition and long-term care. NCS Healthcare recruited 96 facilities for the study. During a three-month period from August to November 1998, consultant pharmacists reviewed the nursing home medical records and most recent MDS of each resident within the facilities. A maximum of 20 residents were chosen per facility. In the final study sample, 900 nursing home residents with a recently identified nutritional problem from 96 long-term care facilities in eight states were randomly selected.


Prospective cohort study. 

Blinding Used 

All data collected from the resident's medical record were blinded and coded in a manner that maintained strict patient and facility confidentiality. 

Statistical Analysis

  • Intra-resident weight variability from month to month was evaluated
  • Cox proportional hazards regression analysis was used to assess relationships between weight parameters and mortality risk during the seven months of observation.
Data Collection Summary:

Timing of Measurements

At study entry, nutritional, health status and demographic data were extracted from the nursing home chart or the Minimum Data Set. Weights were recorded at baseline and during each of the subsequent six months. Survival data collected for seven months.

Dependent Variables

  • Weight measured by the nursing staff
  • Mortality data: Death, discharge or loss to follow-up recorded.

Independent Variables

  • Demographic data
  • Diagnoses
  • Medications
  • Appetite assessment
  • Overall activity of daily living functional capacity
  • Level of feeding dependence
  • Number of pressure sores based on chart on MDS documentation.

Control Variables

  • Age
  • Appetite score
  • BMI
  • Length of stay
  • Number of diagnoses
  • Number of pressure sores.
Description of Actual Data Sample:
  • Initial N: 1,000 residents initially enrolled
  • Attrition (final N): 900 residents, 76% female. 15 were residing in an assisted living bed and 85 died or were discharged before the third month of observation
  • Age: Mean was 86±8 years (range 65 to 104)
  • Anthropometrics: Mean BMI was 21.2±4.1
  • Location: Eight states in the US.
Summary of Results:

Relationship Between Weight Change and Mortality During the Seven Months of Observation

Amount of Weight Change

Unadjusted Relative Risk (95% CI)

Adjusted Relative Risk (95% CI)

Loss of more than 10%

6.5 (2.5 to 16.9) 8.3 (3.1 to 21.8)
Loss of less than 10% 2.9 (1.2 to 7.3) 3.4 (1.3 to 8.5)
Gain of 0% to less than 10% 1.3 (0.5 to 3.5) 1.5 (0.6 to 4.0)

Gain of more than 10%



Other Findings

  • During the study, 435 (48%) participants had at least one monthly weight that differed from the previous month's weight by more than 5%; 163 (18%) participants had this magnitude of a one-month weight change more than once
  • By controlling for the linear trend of each resident's weight change between the first to the last weight, the average month-to-month residual variability in the residents' weight was calculated. This residual variability, or "average random fluctuation," in weight from one month to the next was more than 2% in 229 (25%) participants and more than 3% in 82 (9%) participants.
  • Despite the large random fluctuation in the residents' weights, weight loss was an important prognostic indicator
  • Those who lost more than 5% in any month had a 10-fold increased risk for death compared with those who gained weight (adjusted relative risk, 10.6; 95% confidence interval: 3.2 to 35.5)
  • The average random fluctuation in weight was associated with an increased risk for death only at the upper 10th percentile for the population.
Author Conclusion:

Many nutritionally compromised elderly nursing home residents experience significant bidirectional fluctuations in their weight from month to month. How much of this variability is due to measurement error is not known. However, a weight loss of more than 5% in any month has important prognostic implications.

Funding Source:
Bristol-Myers Squibb
Pharmaceutical/Dietary Supplement Company:
Reviewer Comments:

Large national sample. Authors note that the association between weight fluctuation and death may be confounded by illness severity, as these residents tend to be frailer, more functionally dependent, more difficult to weigh and more likely to experience significant fluid shifts. Authors note the following limitations:

  • Short period of observation
  • Included only residents at nutritional risk
  • Poor measurement technique, medical instability of the residents and other factors may have contributed to the variability in weights
  • Relied solely on data recorded by clinical staff within each facility, untrained to research protocol that would emphasize the importance of using a consistent approach to performing weight measurements, such as using the same scale, taking the weights at the same time of day and ensuring that the resident is wearing the same amount of clothing. 
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) N/A
  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) N/A
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? Yes
  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? Yes
  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? Yes
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? Yes
  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.) Yes
  5.3. In cohort study or cross-sectional study, were measurements of outcomes and risk factors blinded? Yes
  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? ???
  7.1. Were primary and secondary endpoints described and relevant to the question? Yes
  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? ???
  7.4. Were the observations and measurements based on standard, valid, and reliable data collection instruments/tests/procedures? ???
  7.5. Was the measurement of effect at an appropriate level of precision? ???
  7.6. Were other factors accounted for (measured) that could affect outcomes? Yes
  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? Yes
  10.2. Was the study free from apparent conflict of interest? Yes