Unintended Weight Loss in Older Adults

UWL: Association With Outcomes (2009)

Citation:

Shum NC, Hui WW, Chu FC, Chai J, Chow TW. Prevalence of malnutrition and risk factors in geriatric patients of a convalescent and rehabilitation hospital. Hong Kong Med J. 2005; 11(4): 234-242.

PubMed ID: 16085939
 
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:
  1. To assess the prevalence of malnutrition using anthropometric and biochemical parameters
  2. To test the hypothesis that the Chinese MNA is not a useful screening tool for identifying malnutrition in hospitalized geriatric patients
  3. To test the hypothesis that the risk of malnutrition is not increased by depressed mood, impaired cognitive function, functional impairment, polypharmacy, place of residence prior to admission or mobility.
Inclusion Criteria:
  • Patients 60 years or older who were transferred to the geriatric ward of of Tung Wah Eastern Hospital between 12/15/2002 and 3/31/2003
  • Patients originally admitted to Pamela Youde Nethersole Eastern Hospital through the Accident and Emergency Department.
Exclusion Criteria:
  • Patients admitted to a geriatric ward via specialist out-patient clinics or government out-patient clinics
  • Patients with amputation of limbs
  • Patients with terminal cancer
  • Patients that were re-admitted within the study period
  • Patients (or their relatives) that were unable or unwilling to give written informed consent
  • Patients suffering from severe contractures that would not allow accurate measurements of body weight or knee height.
Description of Study Protocol:

Recruitment

Most patients were not recruited for this study. As long as they met inclusion or exclusion criteria and gave written informed consent they were included. However, 12 patients were recruited from a pilot study. The method of recruitment for these 12 patients were not revealed.

Design

Cross-Sectional Study 

Blinding used (if applicable)

Intervention (if applicable)

Statistical Analysis

Multiple statistical analysis were performed, including: 

  • Student's T-tests were used to compare the distribution between malnourished and nourished subjects, to determine if significant differences existed between the sexes of the anthropometric, biochemical, and hematological parameters, and for testing in the differences in geriatric depression scale and abbreviated mental test scores between malnourished and nourished subjects.
  • Chi-squared test was used to determine any significant difference in distribution of age groups between malnourished and nourished patients and to determine the P-values. 
  • One-way analysis of variance and Tukey post-hoc comparison tests were used to determine if there were significant differences in the anthropometric parameters as well as the three biochemical and hemotological parameters between the three age groups.
  • The sensitivity and specificity of the Chinese MNA were analyzed by a 2x2 table. 
Data Collection Summary:

Timing of Measurements

Baseline demographic data was obtained upon admission to the ward. Routine blood tests, including a CBC with differential counts, liver and renal function tests, were performed one day following admission. The Chinese Mini Nutritional Assessment was completed within 48 hours of admission. Risk factors associated with malnutrition were investigated. Functional status, polypharmacy, and mobility were recorded on admission. Depressed mood and impaired cognitive function were evaluated but the time frame for these evaluations was not specified.

Dependent Variables

  • Malnutrition as defined as a BMI less than 18.5kg/m2 and albumin level lower than 35g/L
  • Malnutrition as measured by the Chinese Mini-Nutritional Assessment. Data was collected by a single single investigator
  • Nutritional status was assessed using anthrometic data (height, weight, BMI, knee heel height, triceps skin fold, mid-arm circumference, arm muscle circumference, and corrected arm muscle area), and hematological and biochemical data, using albumin, hemoglobin and lymphocyte count. 

Independent Variables

  • Depressed mood as measured by the Chinese version of the Geriatric Depression Scale
  • Impaired cognitive function as measured by the Chinese version of the Abbreviated Mental Test
  • Functional impairment as measured by self-reporting of ability to perform ADLs
  • Polypharmacy as measured by intake of five or more drugs regularly
  • Baseline demographic data including place of residence prior to admission as obtained from a questionnaire
  • Mobility as measured by ability to walk unaided, with aid, chair-bound or bed-bound
  • Age: Patients were divided into three age-groups; young-old (60-69 years), old (70-79 years) and old-old (≥80 years).

Control Variables 

Description of Actual Data Sample:

Initial N

201 patients met the inclusion and exclusion criteria. Informed consent was obtained from 108 and 12 patients were recruited from a pilot study. Total patients in the study were 120.

Attrition (final N)

Nine patients died during the study period but their data was included in the study results. Only 77 of the 120 patients completed the Chinese Mini-Nutritional Assessment. Reasons for non-completion included absence of informed consent, inability to contact relatives or guardians, or deterioration in cognitive function.

Age

  • Mean age of participants was 80.3 years. Females were older than males (mean 81.8 years vs. 78.7 years). This difference was not statistically significant (->0.05).
  • N for each age group was as follows: age 60-69, N=9,  age 70-79, N=46, age≥80, N=65.

Ethnicity

No information on ethnicity provided; however based on the study location it can be assumed all patients are Chinese.

Other relevant demographics 

  • The gender of participants were similar: 61 females (51% of those studied) and 59 males (49% of those studied)
  • 49% of participants were non-smokers, 38% ex-smokers, and 13% current smokers
  • 66% were non-drinkers, 8% current drinkers, 24% social drinkers, and 2% chronic drinkers
  • 3% of participants were single, 44% were married, and 53% widowed.

Anthropometrics

Weight, BMI, triceps skin fold thickness, mid-arm circumference, arm muscle circumference and corrected arm muscle area were significantly different among the patients of the three age-groups.

Location

Hong Kong, China

 

Summary of Results:

 Distribution of risk factors in malnourished and nourished subjects

Risk Factor Malnourished Subjects Nourished Subjects Odds Ratio* P-value from Chi- squared Test

Depression (GDS≥8)

3/5 13/67 5.25(0.96-28.76) 0.069
Moderately or severely impaired cognitive function (AMT less than seven) 2/7 14/68 1.65 (0.35-7.75) 0.618
Totally dependent (ADL) 12/20 16/100 4.93(2.24-10.87) <0.001
Polypharmacy (greater than five) 5/20 29/100 0.843 (0.33-2.14) 0.793
Living alone 2/20 15/100 0.67 (0.17-2.64) 0.735
Living in old-aged homes 9/20 22/100 2.90(1.07-7.87) 0.0481
Chair or bed-bound 13/20 24/100 4.17(1.81-9.62) 0.002

*95% Confidence Interval

Other Findings

  • Prevalence of malnutrition based on BMI of 18.5 and albumin of less than 35g/L was 16.7% (P=0.00001).
  • The distribution of malnourished patients in the old-old group (≥80 years old) was higher than those in the young-old (60-69) and old (70-79). The distribution was as follows: Young-old (0/9), old (3/43) and old-old (17/48). This distribution was significantly different (P=0.01).
  • A significant difference in hemoglobin was noted between the young old and old-old (130g/L vs. 113g/L) (P=0.05)
  • Based on the Chinese mini-nutrition assessment, the incidence of malnutrition was 16.9%. The malnourished patients had a mean MNA score that was significantly lower than the nourished group.
  • The Geriatric Depression Scale score for depressed mood and Abbreviated Mental Test score for cognitive function did not vary significantly between malnourished and nourished subjects. Risk factors for malnutrition (depression, impaired cognitive function, polypharmacy and living alone) did not differ significantly between nourished and malnutrition subjects.
  • Risk estimates of those who were totally dependent (P=0.0001), living in old-aged homes (P=0.481) and chair- or bed-bound (P=0.002) showed that these conditions were more common in malnourished than in nourished patients
  • Mortality was higher in malnourished patients than in nourished patients.

 

Author Conclusion:

The prevalence of malnutrition in geriatric patients admitted to a convalescent and rehabilitation hospital was 16.7% and is comparable with results of similar studies.

The Chinese Mini Nutrition Assessment had a high negative predictive value and was thus useful as a screening tool in clinical practice to identify malnourished patients.

Patients who were totally dependent, lived in a care home for the elderly or were chair- or bed-bound had a higher risk of malnutrition than others.

Funding Source:
Other: Not reported
Reviewer Comments:
  • Twelve of the study participants were recruited from a pilot study, but no information was provided about the time-frame of that study or on how those 12 patients were recruited.
  • Only 77 of the original 120 patients (64% of participants) completed the Chinese MNA. Reasons for non-completion were outlined and included deterioration in cognitive function.
  • The author concluded that the prevalence of malnutrition (16.7%) among geriatric patients admitted to a convalescent and rehabilitation hospital was high, but the analyst could not identify how it was determined that 16.7% is considered a high rate of malnutrition among this population.
  • In the discussion section, it is mentioned that more than half of the totally dependent patients required enteral feeding to assure adequate nutrition. This confounds the results of the study, as it might be assumed that these patients have a totally different nutrient intake than those who choose their foods freely and may have a higher or lower prevalence of malnutrition as a result of tube feeding.
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) N/A
  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.) 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? ???
  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.) ???
  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? N/A
  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? ???
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)? No
  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? No
  10.2. Was the study free from apparent conflict of interest? Yes