Unintended Weight Loss in Older Adults

UWL: Association With Outcomes (2009)

Citation:

Knoops KTB, Slump E, de Groot LCPGM, Wouters-Wesseling W, Brouwer ML, van Staveren WA. Body weight changes in elderly psychogeriatric nursing home residents. J Gerontol A Biol Sci Med Sci. 2005; 60 (4): 536-539.

PubMed ID: 15933399
 
Study Design:
Prospective longitudinal study
Class:
C - Click here for explanation of classification scheme.
Quality Rating:
Neutral NEUTRAL: See Quality Criteria Checklist below.
Research Purpose:

To identify predictors of body weight change in nursing home patients with possible to severe dementia.

Inclusion Criteria:
  • Aged over 65 years
  • BMI below 35kg/m2
  • Probable presence of dementia
  • Having been in the nursing home for more than three months.
Exclusion Criteria:
  • Having terminal care
  • Cancer
  • Rheumatoid arthritis
  • Diabetes.
Description of Study Protocol:

Recruitment

Study was conducted in a geriatric nursing home in The Netherlands that houses elderly people with possible to severe dementia.

Design

  • Prospective longitudinal study
  • Enrolled residents were followed for 24 weeks.

Statistical Analysis

  • Changes in body weight were calculated by subtracting baseline body weight from the last measurement of body weight
  • A difference of more than 2.0kg was seen as a change in body weight
  • Three body weight change categories were created: Weight loss group (more than 2.0kg lost), weight gain group (more than 2.0kg gained) and a weight-stable group
  • Differences between the three groups were tested by ANOVA, chi-square tests or exact tests
  • A generalized linear mixed-effects model was used to investigate weight changes over time, adjusted for age and sex.
Data Collection Summary:

Timing of Measurements

  • Residents were followed for 24 weeks
  • All measurements were made at baseline
  • Body weight was measured every two weeks.

Dependent Variables

Body weight measured to the nearest 0.1kg on a calibrated balances scale.

Independent Variables

  • Anthropometric characteristics: Height or knee height  
  • Dietary intake was measured with a combined three-day food record and by observations during the hot meals
  • Energy and nutrient intakes were calculated using the Dutch food composition database
  • Food behavior restrictions were measured following the classification of Berkhout
  • Dependency was measured by a questionnaire (Care Index Geriatrics), which measures restrictions in cognitive, physical and social functioning
  • Psychological characteristics
  • Residents appetite, thirst and dental status were recorded
  • Past medical information obtained from medical records: Reports on chronic diseases, cardiovascular, renal, bone fracture and other diseases, cardiovascular accidents, transient ischemic attack, chronic infections, influenza, higher and lower bronchial tube infection, gastrointestinal tract diseases and urinary and other infections 
  • Use of medicines.

Control Variables

  • Age
  • Sex.
Description of Actual Data Sample:

Initial N

  • Of the 192 residents, 46 did not meet inclusion criteria, five had limited psychological functioning and for 31, informed consent could not be obtained
  • 110 residents were enrolled.

Attrition (Final N)

  • 108 residents were included in the analysis
  • For two residents, body weight was assessed only once
  • Of the 108 participants, 17% did not complete the study. 

Age

  • Weight Loss Group: 17% male; mean age, 82.1±7.6 years: 32% dropouts
  • Weight Gain Group: 13% male; mean age, 83.0±7.5 years; 17% dropouts
  • Weight Stable Group: 14% male; mean age, 83.6±7.0 years; 9% dropouts.

Ethnicity

Not mentioned.

Anthropometrics

There were significantly more dropouts in the Weight Loss Group than in the Weight Gain and Weight Stable Groups (P=0.03).

Location

The Netherlands.

Summary of Results:

Variables

Beta 95% Confidence Interval

P-Value

Age at Baseline

-0.09

-0.23, 0.04

0.17

Sex

-8.64

-12.45, -4.83

<0.0001

BMI at Baseline
2.25
1.98, 2.51
<0.0001
ZIG Total Score at Baseline
-0.11
-0.21, -0.01
0.039
Intake of Fat (g per Day) at Baseline
0.07
0.01, 0.13
0.027
Decreased Appetite (Yes or No)
-2.16
-4.32, -0.01
0.049
Difficulties with Bringing Food to Mouth (Yes or No)
2.51
-0.15, 5.16
0.064

Other Findings

  • Mean body weight change was -0.14kg (range, -12.7 to +8.9)
  • During the follow-up period, 26% of the participants lost (mean, -4.1kg) and 22% gained (mean, 4.0kg) at least two kg of body weight
  • Dependency (beta, -0.11; 95% confidence interval, -0.21, -0.01) and decreased appetite (beta, -2.17; 95% confidence interval, -4.32, -0.01) were significantly associated with body weight loss.
  • Body mass index (beta, 2.25; 95% confidence interval, 1.98, 2.51) and intake of fat (beta, 0.07; 95% confidence interval, 0.01, 0.15) were predictors of weight gain
  • The effect of difficulties (beta, 2.51; 95% confidence interval, -0.15, 5.16) with bringing food to the mouth was only borderline significant
  • In this study, chronic diseases, chronic infections in the past, pressure ulcers, acute infections, medicine use, decreased thirst, not having all teeth, problems with chewing or swallowing, energy intake, protein intake and carbohydrate intake were not associated with body weight changes.
Author Conclusion:

Although this study has some limitations, it seems to be that further decrease in cognitive functioning, the intake of fat, BMI and a decreased appetite are associated with body weight changes.

Funding Source:
Industry:
Numico Research B.V.
Other:
Reviewer Comments:
  • All residents were from one nursing home and were only followed for 24 weeks
  • High dropout rates
  • Authors note the following limitations:
    • Edema was not well registered
    • Due to the small number of weight losers and weight gainers, the power for detecting differences in other predictors, for example chronic diseases, pressure ulcers and chronic infections in the past, was possibly too low.
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? ???
  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? ???
3. Were study groups comparable? ???
  3.1. Was the method of assigning subjects/patients to groups described and unbiased? (Method of randomization identified if RCT) Yes
  3.2. Were distribution of disease status, prognostic factors, and other factors (e.g., demographics) similar across study groups at baseline? ???
  3.3. Were concurrent controls or comparisons used? (Concurrent preferred over historical control or comparison groups.) Yes
  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? ???
  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%.) No
  4.3. Were all enrolled subjects/patients (in the original sample) accounted for? ???
  4.4. Were reasons for withdrawals similar across groups? ???
  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? N/A
  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? Yes
  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? Yes
  7.6. Were other factors accounted for (measured) that could affect outcomes? Yes
  7.7. Were the measurements conducted consistently across groups? Yes
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? No
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