EAL

COPD: Bone Density (2008)

Citation:

Study Design:

Class:

- Click here for explanation of classification scheme.

Quality Rating:

Research Purpose:

The purpose of this study was to compare the degree of osteoporosis and bone metabolism markers between elderly women with COPD and those with bronchial asthma who have never received chronic systemic corticosteroids, and to determine the factors influencing bone metabolism in these patients.

Inclusion Criteria:

Elderly female Japanese patients with COPD and bronchial asthma followed at the outpatient clinic of Tokyo Metropolitan Geriatric Medical Center.

Exclusion Criteria:

Coexisting medical disorder that might affect bone metabolism or if they had received medications known to affect bone metabolism apart from inhaled corticosteroids.

Description of Study Protocol:

Recruitment Subjects were recruited from the outpatient clinic of Tokyo Metropolitan Geriatric Medical Center with the diagnoses of COPD and bronchial asthma. The criteria for the diagnoses were based on the American Thoracic Society standards. None of the patients had a history of chronic systemic corticosteroid use, defined as any oral steroids received continuously for > 1 week in the previous 10 years. All were postmenopausal.

Design: Cross-sectional survey. Total body and lumbar bone mineral density (BMD) were measured by dual-energy x-ray absorptiometry, and the data were compared between the two groups. In addition, the association between bone mass and clinical variables was determined.

Blinding used (if applicable): None

Intervention (if applicable): Not applicable

Statistical Analysis

An unpaired Student t-test and X2 test were used to compare differences between patients with bronchial asthma and patients with COPD. Relationships between the variables were assessed with Pearson correlation coefficients.

Data Collection Summary:

Timing of Measurements: one time measurement

Dependent Variables

Bone mineral density (dual-energy x-ray absorptiometry of the total body and lumber spine)
Lung Function (FVC, FEV1)
Bone metabolism markers (intact parathyroid hormone, osteocalcin, total urinary deoxypyridinoline)

Independent Variables

Bronchial asthma versus COPD

Control Variables

Menopausal status

Description of Actual Data Sample:

Initial N: 20 COPD, 24 bronchial asthma

Attrition (final N): as above

Age: 72.3 ± 13 years for COPD subjects, 76.6 ± 1.5 years for bronchial asthma subjects

Ethnicity: Not mentioned

Other relevant demographics:

All the COPD group were ex-smokers, none in the bronchial asthma group

Anthropometrics

Patient characteristics, anthropometric variables and details of inhaled steroid use of the study group
Variables	COPD	Bronchial asthma	p value
FEV1 (L)	0.94 ± 0.08	1.17 ± 0.08	<0.04
FEV1 (% predicted)	49.9 ± 3.8	66.5 ± 3.8	<0.01
BMI	22.0 ± 0.8	24.6 ± 0.9	<0.04
Duration of inhaled steroid use (months)	20.1 ± 5.4	39.5 ± 6.1	<0.03
Total amount of inhaled steroid use, mg	288.3 ± 78.9	743.2 ± 178.9	<0.04

Location:

Tokyo Japan

Summary of Results:

Variables	COPD Group Mean SEM	Bronchial asthma group Mean SEM	p Value
Total body BMD g/cm²	0.89 ± 0.02	0.98 ± 0.02	<0.01
Spine BMD g/cm²	0.80 ± 0.04	1.01 ± 0.04	<0.001
Spine Z score	-0.33 ± 0.27	1.08 ±0.34	<0.01
Spine T score	-2.54 ± 0.32	-1.01 ± 0.35	<0.01

Other Findings

50% of the COPD group and 21% of the bronchial asthma group received a diagnosis of osteoporosis based on Japanese criteria (p<0.05).

There were no differences between the two groups in terms of urinary and serum bone metabolism markers.

The BMI of the patients with COPD was positively correlated with total body BMD (r=0.49, p =0.03) and the BMD of the lumbar spine (r=0.55, p=0.02).

Author Conclusion:

In elderly female patients, osteoporosis is more common in cases of COPD than in bronchial asthma, even if these patients had not received long-term systemic corticosteroids. The explanation for the higher prevalence of osteoporosis in COPD is still not known, but the preventative strategies to decrease osteoporotic fractures should be added to the management of elderly patients with COPD.

Funding Source:

Reviewer Comments:

Significant differences between groups in terms of smoking status and BMI. Authors note limitations of not including a healthy control group and that severe cases may have been excluded since only patients not receiving long-term systemic corticosteroid therapy were enrolled. Only women in the study limits generalizability to men.

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?		???
	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?	No
	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?		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?	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?		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?	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?	Yes
	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?	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)?	Yes
	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