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COPD: Effectiveness of Therapies (2007-2008)

Citation:
 
Study Design:
Class:
- Click here for explanation of classification scheme.
Quality Rating:
Research Purpose:
To evaluate the effects on energy intake and body weight of an intensified nutritional support compared to the regular support during hospitalization.
Inclusion Criteria:
  • Underweight and normal weight patients with end-stage pulmonary disease assessed for lung transplantation
  • Willingness to participate and ability to cooperate by eating assigned diet
Exclusion Criteria:
  • Unwillingness to participate and eat prescribed diet
  • Too sick to be able to cooperate
  • Leave of absence and eating meals away from hospital
Description of Study Protocol:

Recruitment

Patients were referred to hospital from all over Norway to be evaluated for lung transplantation.  71 consecutive underweight and normal weight patients enrolled in the study between August 1993 and August 1998.

Design:  Randomized Controlled Trial.  Underweight patients were randomized using random number tables stratified by age and sex.

Blinding used (if applicable):  not possible with interventions, apart from dietitian who was responsible for diet allocation, none of investigators performing measurements knew which group patients belonged to.

Intervention (if applicable)

  • Underweight patients randomized to receive either energy-rich diet planned for 10 MJ/day and 45 - 50% energy from fat and offered supplements (Group 1) or the normal hospital diet planned for 8.5 - 9 MJ/day and 35 - 35% energy from fat (Group 2)
  • Normal weight control patients received normal diet (Group 3)

Statistical Analysis

Student's t test was used for comparisons of baseline characteristics between groups.  Differences in weight change and dietary data between groups were tested for statistical significance using Wilcoxon's signed rank test.  Two-way ANOVA used to test whether sex influenced the differences in energy intake between groups.  Post hoc analysis with Bonferroni correction was performed on residuals to control differences between groups for energy intake.  Spearman's rank correlation coefficient was used to show the association between energy from nutritional supplements and total energy intake. 

Data Collection Summary:

Timing of Measurements

Measurements made upon arrival at hospital and repeated at end of hospital stay.

Dependent Variables

  • Body weight, height, BMI
  • Triceps skinfold measurements using Harpenden calipers 
  • Mid-upper arm circumference
  • Lung function measured using automated pulmonary function unit
  • Serum albumin measured colorimetrically
  • Serum creatinine, potassium and phosphate concentrations and urinary creatinine measured with routine methods
  • Muscle strength measured using handgrip dynamometer

Independent Variables

  • Underweight patients randomized to receive either energy-rich diet planned for 10 MJ/day and 45 - 50% energy from fat and offered supplements (Group 1) or the normal hospital diet planned for 8.5 - 9 MJ/day and 35 - 35% energy from fat (Group 2)
  • Normal weight control patients received normal diet (Group 3)
  • Food intake recorded for 3 days

Control Variables

  • Energy intake
Description of Actual Data Sample:

Initial N: 42 underweight and 29 normal weight patients

Attrition (final N):  65 subjects:  18 in Group 1 (8 male, 10 female), 19 in Group 2 (10 male, 9 female), 28 in Group 3 (12 male, 16 female).  6 were excluded - 1 did not want the energy-rich diet, 1 had particular dietary wishes, 1 had leave of absence, 1 had short stay, and 2 died.

Age:  mean age Group 1:  49 years (range 44 - 53 years), Group 2:  48 years (range 44 - 52 years), Group 3:  51 years (48 - 55 years)

Ethnicity:  not mentioned

Other relevant demographics:

Anthropometrics: 

Location:  Norway

 

Summary of Results:

Weight Change during the hospital stay, BMI after intervention, total energy intake per kg of body weight and total energy intake compared with REE predicted by Harris-Benedict equation:

 

Group 1

Group 2

Group 3

Weight change, (median) kg

 1.2 (p < 0.01) 0 -0.3 (p < 0.001)
BMI 18.3 +/- 1.7 17.0 +/- 2.2 (p < 0.001) 22.2 +/- 1.6 (p < 0.001)

Total intake (median), kJ/kg

215

169 (p < 0.01)

111 (p < 0.001)

Total intake/REE predicted (median), %

217 (p < 0.02)

151 (p < 0.03)

126 (p < 0.001)

Other Findings

During mean hospital stay of 12 days, energy intake was significantly greater for the patients on intensified nutritional support (median 11.2 MJ) than for the underweight patients on the regular support (8.4 MJ, p < 0.02) and the normal weight patients (7.0 MJ, p < 0.001).

The increase in energy intake in Group 1 resulted in a significant weight gain (median 1.2 kg) compared with Group 2 (p < 0.01) and group 3 (p < 0.001). 

Author Conclusion:
In summary, it was possible, during a short hospital stay, to increase the energy intakes and body weights of underweight patients assessed for lung transplantation by an intensified nutritional support compared to the normal diet and regular support.  In this group of patients, an energy-rich diet could be recommended and for additional support they might routinely be offered ready-made, liquid nutritional supplements.
Funding Source:
Reviewer Comments:
Measurements made over 5 year study length.  Authors note that short hospital stay a clear improvement in nutritional status could not be expected; weight gain may be more attributed to water.
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? ???
  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.) No
  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? 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? 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? 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? 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? ???
  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? ???
  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