Unintended Weight Loss in Older Adults

UWL: Association With Outcomes (2009)

Citation:

Purandare N, Burns A, Craig S, Faragher B, Scott K. Depressive symptoms in patients with Alzheimer's disease. Int J Geriatr Psychiatry. 2001; 16 (10): 960-964.

PubMed ID: 11607939
 
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 evaluate whether depressive symptoms occurred in patients with Alzheimer's Disease in the absence of co-existing major depression
  • To identify those that are able to differentiate Alzheimer's Disease from major depression
  • To describe those symptoms common to both disorders.

 

Inclusion Criteria:

Patients were diagnosed according to the DSM-III-R criteria for primary degenerative dementia of the Alzheimer type and major depression.

Exclusion Criteria:

None specifically mentioned.

Description of Study Protocol:

Recruitment

A convenience sample of consecutive patients suffering from either Alzheimer's Disease or major depression seen over a six-month period were recruited from a specialist old age psychiatry service in South Manchester, which serves an urban population over the age of 65 years.

Design

Cross-sectional study.

Blinding Used

Diagnosis was made independently of the researcher who carried out the clinical assessments.

Statistical Analysis

  • Age followed a normal distribution and was analyzed using parametric statistical methods (mean, standard deviation and Student's unpaired T-test)
  • Data from all three depression scales exhibited positively skewed distributions and were evaluated using median, interquartile range and Mann-Whitney U-test
  • Gender distribution of the study cohorts was compared using frequency counts and Fisher's exact test
  • Individual discriminant function analyses were carried out for each of the three depression scales to identify the minimum combinations of items best able to differentiate statistically those patients with major depression from Alzheimer's Disease and the percentages of patients correctly classified were computed.
Data Collection Summary:

Timing of Measurements

All measurements were made while patients were seen over a six-month period.

Dependent Variables

  • Cognitive function was assessed using the Mini-Mental State Examination
  • Depressive symptoms were profiled using the Hamilton Depression Rating Scale, the Cornell Scale for Depression in Dementia, and the Geriatric Depression Scale.

Independent Variables

Alzheimer's Disease or major depression.

Control Variables

Demographic information: Age, sex, duration of illness and current treatment.

Description of Actual Data Sample:
  • Initial N: 30 patients with Alzheimer's disease, 30 with major depression
  • Attrition (final N): As above
  • Age: See Results
  • Location: United Kingdom. 
Summary of Results:

Description of the Sample

Variables

Alzheimer's Disease

Major depression

Significance of Difference

Number

30
30
N/A

Diagnosis

DSM-III-R

DSM-III-R

N/A

Age (Years)
79.9±6.2
75.8±5.5
P<0.01
Sex (Male:Female)
8:22
4:26
P=0.33
Mini-Mental State Examination
20 (15 to 23)
27 (25 to 29)
P<0.001 
Hamilton Depression Rating Scale
8.5 (3 to 13)
26.5 (24 to 30)
P<0.001
Cornell Scale for Depression in Dementia
5 (2 to 11)
19 (16 to 22)
P<0.001
Geriatric Depression Scale
8 (5 to 13)
21 (17 to 24)
P<0.001

Other Findings

  • Patients with Alzheimer's Disease were older, but there was no sex difference between the groups
  • Depressive symptoms were present in Alzheimer's Disease in the absence of co-existent major depression
  • Certain depressive symptoms from all the three scales such as sadness, diurnal variation in mood and early or late insomnia were able to differentiate the two disorders with almost 90% accuracy while symptoms such as irritability, retardation and weight loss were common to both and were unable to differentiate the two. 
Author Conclusion:
  • The main findings of this study were that depressive symptoms occur in Alzheimer's Disease in the absence of major depression and that some depressive symptoms are common to both
  • Depressive symptoms occur in Alzheimer's Disease when co-existing depression is ruled out. Their recognition has implications for the diagnosis of major depression in these patients.
Funding Source:
Other: Not reported
Reviewer Comments:

Small numbers of subjects in groups. Authors note the following limitations:

  • Age- and sex-matched healthy control group were not included
  • Study sample was convenience sample with a possible pre-selection bias.
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) Yes
  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) Yes
 
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) 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? 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? Yes
  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? Yes
  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? Yes
  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? 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? N/A
  6.7. Was the information for 6.4, 6.5, and 6.6 assessed the same way for all groups? Yes
  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? Yes
  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? 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? 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? 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