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COPD: Determination of Energy Needs (2007)

Citation:

Mosier K, Renvall MJ, Ramsdell JW, Spindler AA.  The effects of theophylline on metabolic rate in chronic obstructive lung disease patients.  J Am Coll Nutr 1996;15(4):403-7.

PubMed ID: 8829097
 
Study Design:
Randomized Crossover Trial
Class:
A - Click here for explanation of classification scheme.
Quality Rating:
Neutral NEUTRAL: See Quality Criteria Checklist below.
Research Purpose:

To study the effect of theophylline and an alternative bronchodilator, ipratropium, on resting energy expenditure and thermic effect of food.

Inclusion Criteria:
  • At least 65 years old
  • Clinical diagnosis of COPD with FEV1 <70% predicted, FEV1/FVC < 70%
  • Capable of maintaining a respiratory symptom diary
Exclusion Criteria:
  • Current or recent (within 2 weeks) respiratory tract infection
  • COPD exacerbation within 1 month of start of titration phase
  • Requirement for maintenance oral corticosteroid therapy
Description of Study Protocol:

Recruitment

Patients recruited from faculty practice of University of California, San Diego.

Design

Randomized, repeated measures crossover trial.

Blinding used (if applicable)

Double blind.

Intervention (if applicable)

Subjects took theophylline or ipratropium for 2 weeks, followed by 1 week washout period, and then 2 weeks on the alternative drug.  Drug levels were 2 puffs (36 mcg) 4 times per day.  During washout period, subjects received placebo tablets and placebo inhaler.

Statistical Analysis

REE and TEF analyzed by repeated measures ANOVA followed by Scheffe post hoc analysis.  Data grouped for all subjects and then analyzed by gender.  Potential effects on REE and TEF of the covariates age, drug sequence, and COPD severity were estimated by ANCOVA.

Data Collection Summary:

Timing of Measurements

2-week titration period prior to study to determine optimal theophylline dosage.  All measurements taken at the end of each 2 week period.

Dependent Variables

  • BMI
  • Resting energy expenditure and thermic effect of food measured by indirect calorimetry
  • Body composition measured with bioimpedance
  • Girth circumferences at waist and hip with tape measurement
  • Dietary intake assessed from 4-day food records
  • Activity level through Blair Seven-Day Physical Activity Record 

Independent Variables

  • Theophylline or ipratropium for 2 weeks

Control Variables

 

Description of Actual Data Sample:

Initial N: 15 patients

Attrition (final N):  14 completed, 1 dropped out due to illness

Age:  mean age men:  72 +/- 4 years, women: 74 +/- 6 years, overall:  74 +/- 5 years

Ethnicity:  not mentioned 

Other relevant demographics: 12 had been on theophylline prior to study

Anthropometrics:

Location:  University of California, San Diego

 

Summary of Results:

 

 

Baseline Ipratropium Theophylline Calculated

MREE - Men

1628 +/- 284

1590 +/- 256

1560 +/- 160

1588 +/- 327

MREE - Women

1368 +/- 163

1333 +/- 135

1376 +/- 203

1229 +/- 71

MREE - All

1438 +/- 219

1454 +/- 229

1502 +/- 240

1438 +/- 219

TEF - Men 330 +/- 115 454 +/- 136 449 +/- 107 108 +/- 30
TEF - Women 265 +/- 75 260 +/- 65 244 +/- 87 99 +/- 25
TEF - All 301 +/- 100 359 +/- 138 339 +/- 138 103 +/- 26

Other Findings

Resting energy expenditure did not differ between baseline and either of the 2 drug treatments.  ANCOVA indicated no effect of drug sequence, age, gender or FEV1 on measured REE.

Measured REE was similar to predicted REE based on Harris-Benedict.

ANOVA on TEF data showed no differences across the 3 drug trials in all subjects.

In men, thermic effect of food increased significantly during theophylline and ipratropium drug treatment periods (p < 0.03). 

Mean total expenditure values calculated from the sum of REE, TEF and activity expenditure totaled 2700 kcal/day for men and 2200 kcal/day for women, or 33 kcal/kg for men and 34 kcal/kg for women.

Author Conclusion:

In this group of well-nourished COPD patients, resting energy expenditure was not affected by therapeutic doses of theophylline or ipratropium.  The elevated values for the thermic effect of food in men need further study.

Funding Source:
Reviewer Comments:
Small sample size, all faculty members.  2 weeks may not be sufficient duration to see effect.  No power calculations done.  12 had been on theophylline prior to 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) 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? 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? ???
  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? N/A
  6.3. Was the intensity and duration of the intervention or exposure factor sufficient to produce a meaningful effect? ???
  6.4. Was the amount of exposure and, if relevant, subject/patient compliance measured? ???
  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? 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? ???
  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? ???
  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? 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? No
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