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UWL: Association With Outcomes (2009)

Citation:
 
Study Design:
Class:
- Click here for explanation of classification scheme.
Quality Rating:
Research Purpose:

To determine the association between a previously validated frailty phenotype (which includes weight loss, exhaustion, slow walking, sedentariness and weak grip) and the development of new-onset dependence in activities of daily living, independent of hospitalizations, in a prospective cohort of community-dwelling, moderately disabled older women who were indepndent in activities in daily living at enrollment.

Inclusion Criteria:
  • Female gender
  • 65 years old or older
  • Resident of Eastern Baltimore city and county
  • Mini-Mental State Exam Score 18 or greater
  • Self-report of difficulty or dependence with tasks in two or more of the following functional domains: Mobility, upper extremity function, higher functioning tasks and self-care tasks
  • Independent in the following five activities of daily living: Toileting, bathing, transferring, eating and dressing.
Exclusion Criteria:
  • Dependent in one or more of the following five activities of daily living: Toileting, bathing, transferring, eating, and dressing
  • Not a subject in the Women's Health and Aging Study (Sample of 32,538 age-stratified women in Eastern Baltimore obtained from 1992 Medicare Data).
Description of Study Protocol:

Recruitment 

Randomly selected women who agreed to an in-home interview and met the inclusion criteria above.

Design

Prospective cohort study.

Intervention

In-home interview every six months for three years.  Weight measured (with other frailty criteria) at baseline only. 

Statistical Analysis 

SPSS and Stata Version 7.0 were used to analyze categorical variables with contingency tables and perform the chi-squared or Fischer exact test, as appropriate. P-values were two-sided and considered significant statistically if less than 0.05. Bivariate and multivariate analyses were performed. 

 

Data Collection Summary:

Timing of Measurements 

Every six months for three years.

Dependent Variables

New onset dependence in activities of daily living  (assessed via questionnaire: "Do you usually receive help from another person in 'toileting,' bathing, transferring, eating and dressing?").

Independent Variables

  • Frailty (Five defining criteria. One is frail with the presence of three or more of the following):
    • Shrinking: Self-reported weight at age 60. Weight at baseline exam is greater than or equal to 10% of weight at age 60 (i.e., 10% or more loss of self-reported weight at age 60)
    • Exhaustion: Self report
    • Low physical activity: 90 kilocalories or less per week on activity scale for walking, household chores, outdoor chores, dancing, bowling or regular exercise
    • Slowness: Timed walk over four meters, adjusted for height
    • Weakness: Grip strength using a handheld dominant-hand dynamometer adjusted for BMI
  • Hospitalizations (Self-report)
  • Cognitive Function (Mini-Mental State Exam)
  • Depressive Symptoms (Geriatric Depression Scale)
  • Demographics
  • Medical diagnoses.

Control Variables

Adjusted for age, race, education, self-reported health status, baseline difficulty with ADLs, baseline difficulty walking one-fourth mile or up 10 steps, presence of four or more chronic conditions, Mini-Mental State Exam score, Geriatric Depression Scale Score and hospitalization).

Description of Actual Data Sample:
  • Initial N: 784 women
  • Attrition (final N): 749 women (96%)
  • Age: 78±7.9 years
  • Ethnicity: 28% African Americans, 72% other
  • Other relevant demographics: 25% of 749 women were frail at baseline, 58% has nine or more years of education, 80% had Mini-Mental State Exam scores greater than 24, 61% had difficulty with one or more activities of daily living at baseline but no dependency
  • Location: In-home interviews in Eastern Baltimore.
Summary of Results:

 

Variables

Adjusted Hazard Ratio for New-onset Dependence in Activities of Daily Living (95% Confidence Ratio)

Statistical Significance of Group Difference

Shrinking

1.60 (1.20 to 2.12)

P value less than 0.05

Weakness

1.06 (0.81 to 1.39)

Not significant

Slowness

1.96 (1.43 to 2.70)

P value less than 0.05

Low physical activity

1.44 (1.12 to .87)

P value less than 0.05

Exhaustion

0.94 (0.67 to 1.31)

Not significant

*Adjusted for age, race, education, self-reported health status, baseline difficulty with ADLs, baseline difficulty walking one-fourth mile or up 10 steps, presence of four or more chronic conditions, Mini-Mental State Exam score, Geriatric Depression Scale score and hospitalization.

Other Findings

  • Frailty was independently associated with the development of dependence in activities of daily living: Adjusted (as above*) hazard ratio = 2.2; (95% confidence interval 1.4 to 3.6)
  • A dose dependent relationship exists between the number of frailty criteria at baseline and the development of new-onset dependence in activities of daily living. Hazard ratio for presence of one criterion; 1.33 (0.82 to 2.16) vs. presence of four to five criteria; 2.38 (1.33 to 4.25). 
Author Conclusion:

Frailty, conceptualized as underlying vulnerability and hospitalization, which marks acute deterioration in health, were strongly and independently associated with new-onset dependence in activities in daily living.

Funding Source:
Other:
Reviewer Comments:
  1. This study did not classify participants as underweight and did not use BMI in the multivariate analysis. It did not examine the direct relationship between underweight or weight loss and dependence in daily living.
  2. The "Shrinking" parameter in the Frailty phenotype relied upon self-reported weight at age 60 years. The precision of this parameter may have been affected by recall bias.
  3. After baseline measurements, study relies upon subject or proxy report for outcome variables. The reliance on self-report to obtain information on variables, including weight, resulted in a neutral quality rating for the study. Also, weighing procedure at baseline is not described and there is no information provided on the interviewers in the study.
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? Yes
  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? 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.) 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? No
  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? No
  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? No
  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.) N/A
  5.3. In cohort study or cross-sectional study, were measurements of outcomes and risk factors blinded? No
  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? ???
  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? No
  6.3. Was the intensity and duration of the intervention or exposure factor sufficient to produce a meaningful effect? Yes
  6.4. Was the amount of exposure and, if relevant, subject/patient compliance measured? Yes
  6.5. Were co-interventions (e.g., ancillary treatments, other therapies) described? Yes
  6.6. Were extra or unplanned treatments described? Yes
  6.7. Was the information for 6.4, 6.5, and 6.6 assessed the same way for all groups? No
  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? No
  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? No
  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? 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)? No
  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