Unintended Weight Loss in Older Adults

UWL: Nutritional Status (2009)

Citation:

Bedard M, Molloy DW, Bell R, Lever JA. Determinants and detection of low body mass index in community-dwelling adults with Alzheimer's disease. International Psychogeriatrics. 2000; 12(1): 87-98.

PubMed ID: 10798456
 
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:

To determine the proportion of older adults with Alzheimer's disease presenting to a geriatric clinic with low body mass index (BMI), the proportion of these individuals recognized by clinicians as malnourished and what patients' characteristics and caregivers' and clinicians' impressions are associated with low BMI.

Inclusion Criteria:
  • All patients who completed a baseline assessment at the outpatient geriatric clinic between 1988 and 1997 were eligible
  • Patients with dementia of the Alzheimer's type.
Exclusion Criteria:

None specifically mentioned.

Description of Study Protocol:

Recruitment

All patients who completed a baseline assessment at the outpatient geriatric clinic between 1988 and 1997 were eligible. Patients were referred to the clinic for memory or behavior problems by general practitioners and other specialists. Approximately 50% of all referrals were for patients with dementia of the Alzheimer's type.

Design

Cross-sectional study. 

Statistical Analysis

  • Descriptive analyses (means and percentages) were used to present demographic information
  • The kappa statistic was used to calculate the agreement between clinician's report on risk of malnutrition and low BMI
  • To determine variables associated with low BMI, groups were compared using odds ratios with 95% confidence intervals
  • To examine the independent contribution of variables to BMI status, logistic regression using backwards elimination was conducted.
Data Collection Summary:

Timing of Measurements

Data obtained at the baseline visit was used for all analyses.

Dependent Variables

  • Weight, height, BMI and medical information were obtained from patients and caregivers by clinicians using a standardized assessment protocol
  • Clinicians' impressions regarding evidence of malnutrition was also obtained through special forms during clinical interviews and examinations 
  • Cognition was determined using the Mini-Mental State Examination
  • Mood was evaluated with the Geriatric Depression Scale
  • Ability to perform Activities of Daily Living (ADL) was determined with an instrument developed by Lawton and Brody.

Independent Variables

Alzheimer's disease.

Description of Actual Data Sample:
  • Initial N: 1,484 patients were referred during the data collection period. 732 (49.3%) were given a diagnosis of Alzheimer's disease. Weight and height were available for 340 (46%) patients. 
  • Attrition (final N): 340 patients with Alzheimer's disease were included in analyses; 62% were female
  • Age: Mean age, 75 years
  • Other relevant demographics: Overall, patients were moderately demented (SMMSE=19.6, Reisberg scale = 3.6), were not depressed (GDS=7.8) and were taking 3.6 medications.
  • Location: Canada. 
Summary of Results:

Associations Between Patient Characteristics and Low BMI (<21)

Variables

Odds Ratio 95% Confidence Interval

Age more than 85

1.37 0.53 to 3.51
Female gender 5.13 2.24 to 11.74
Duration more than three years 1.29 0.71 to 2.37
SMMSE less than 20 1.76 0.97 to 3.20
GDS more than 15 1.26 0.52 to 3.04
ADL less than 40 2.24 1.06 to 4.74
Feeding less than four 1.70 0.53 to 5.47
Shopping (less than three) 1.58 0.85 to 2.96
Food preparation (less than three) 1.59 0.83 to 3.02
Receives no support 1.51 0.68 to 3.35
Lives alone 1.02 0.49 to 2.11
Smokes 1.78 0.82 to 3.88
Drinks 1.55 0.83 to 2.88

Number of medications

0.95 

0.47 to 1.91

Other Findings

  • The mean BMI was 25.4±4.5 and ranged from 15.3 to 44.8
  • 46 patients (16%) had a BMI below 21
  • Of all 46 with low BMI, clinicians reported evidence of potential malnutrition in 11 patients, eight of whom had a BMI below 21
  • Using logistic regression, women were five times more likely to have a BMI below 21 than men (odds ratio = 5.13, 95% confidence interval = 2.24 to 11.74)
  • Individuals with low cognition were twice as likely to have a BMI below 21 than individuals with higher cognition (odds ratio = 2.24, 95% confidence interval = 1.06 to 4.74)
  • None of the caregivers' answers to questions were associated with low BMI
  • Several clinicians' impressions were associated with low BMI, including a loss of appetite (odds ratio = 2.38, 95% confidence interval = 1.23 to 4.58), presence of diarrhea (odds ratio = 2.79, 95% confidence interval = 1.24 to 6.30), and evidence of malnutrition (odds ratio = 16.35, 95% confidence interval = 4.18 to 63.89). 
Author Conclusion:

The proportion of patients with Alzheimer's disease with a BMI below 21 is similar to that encountered in the general population aged 65 years or more.  However, clinicians have difficulty identifying persons at risk of malnutrition according to BMI status. Women with low cognition were at increased risk of having a low BMI. Improvement in the detection of malnutrition is desirable. Further exploration of causal links between cognition and malnutrition is required.

Funding Source:
Not-for-profit
0
Foundation associated with industry:
Reviewer Comments:

All subjects were from same outpatient geriatric clinic. Some measurements were not made with instruments shown to be valid or reliable. Authors note the following limitations:

  • Measurement of malnutrition, relied on BMI as the sole indicator of nutritional status 
  • Sample size may be too small to detect statistically significant differences between variables in study and BMI.
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? ???
  2.2. Were criteria applied equally to all study groups? ???
  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? Yes
  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? Yes
  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? Yes
  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.) Yes
  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? ???
  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? N/A
  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? 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