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COPD: Bone Density (2008)

Citation:
 
Study Design:
Class:
- Click here for explanation of classification scheme.
Quality Rating:
Research Purpose:
To determine the specific incidence and major risk factors for osteoporosis in those at high risk for falling in a Veterans Administration nursing home that included a high proportion of psychiatric patients.
Inclusion Criteria:
  • Veterans Administration Medical Center nursing home residents with high fall risk
  • Previous episode of falling or who were considered to be at high fall risk
Exclusion Criteria:
None specifically mentioned.
Description of Study Protocol:

Recruitment

Chart review of residents in the VA nursing home was conducted between January and July 1997.

Design:  Retrospective Cross-sectional analysis 

Blinding used (if applicable):  not applicable 

Intervention (if applicable):  not applicable 

Statistical Analysis

  • Descriptive statistics used to describe the demographic, clinical, laboratory and BMD characteristics of the patients. 
  • Parametric and nonparametric statistics (Pearson and Spearman rank statistics) were used to determine the correlation between osteoporosis and specific risk factors. 
  • Chi-square statistics with the Yates correction or the Fisher exact test were used to compare proportions of different risk factors in patients who had already been diagnosied and in those who had not yet been diagnosed with osteoporosis. 
  • An odds ratio with corresponding 95% confidence limits was also determined as a measure of the association between risk factors and disease.
Data Collection Summary:

Timing of Measurements

Review of medical histories and pertinent hormonal and biochemical laboratory values was performed and bone mineral density measured.

Dependent Variables

  • Bone mineral density of right hip and lumbar spine measured by DEXA; 9 subjects uncooperative and were unable to complete DEXA scanning 
  • Laboratory testing included SMA20, albumin level, thyroid-stimulating hormone, follicle-stimulating hormone, luteinizing hormone, testosterone level and prolactin level; not all laboratory measures made in all subjects

Independent Variables

  • High fall risk

Control Variables

  • Age
  • Race
  • Height
  • Weight
  • Main diagnosis
  • Use of steroids
  • Use of antiepileptic medications
  • Use of antipsychotic medications
  • History of smoking
  • History of alcohol abuse
  • Immobilization
  • History of COPD, cerebral vascular accident, gastrectomy, chronic liver disease, inflammatory bowel disease, acute infection, malignancy or hyperparathyroidism
Description of Actual Data Sample:

Initial N: 39 men 

Attrition (final N):  39 men

Age: mean age 74.7 +/- 6.8 years

Ethnicity:  95% White, 5% Black

Other relevant demographics:

Anthropometrics:

Location:  VA Medical Center, Northport, Long Island

 

Summary of Results:

 Presence of risk factors in the normal vs abnormal bone mineral density groups

Variables

Normal BMD (n=8)

 Abnormal BMD (n=30)

Smoking

 12.5% 43.4%

Malnutrition

37.5%

46.7%

Immobility

37.5%

13.3%
Antipsychotic Medication Use 50.0% 53.3%

Other Findings

Only 21% were found to have both normal lumbar spine and right hip BMD.

26% had osteoporosis and 53% had osteopenia.

There was a significant association between COPD and osteoporosis independent of oral corticosteroid use (p = 0.00045).

Additional risk factors found to be associated with osteoporosis included hypogonadism, lower body weight, antipsychotic medication use and smoking.

Author Conclusion:
In a Veterans Administration nursing home population at high risk for falls, including psyciatric patients, COPD independent of the use of corticosteroids, lower body weight, hypogonadism, use of antipsychotic medications and smoking were found to be associated with osteoporosis.
Funding Source:
Reviewer Comments:
Small sample size.  High falling risk not well described.  Limited generalizability.  DEXA and laboratory measurements not made in all patients.  Authors note that since most of the COPD patients weighed less than their IBW, lower body weight alone or in combination with other risk factors could be the cause of osteoporosis.
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? N/A
  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? 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? 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? 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? Yes
  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? N/A
  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? N/A
  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? ???
  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)? 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