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MNT: Cost Effectiveness, Cost-benefit, or Economic Savings of MNT (2009)

Citation:

Johannesson M, Fagerberg B. A health-economic comparison of diet and drug treatment in obese men with mild hypertension. J Hypertension. 1992; 10: 1063-1070. 

PubMed ID: 1328366
 
Study Design:
Cost-effectiveness analysis of a randomized trial.
Class:
A - Click here for explanation of classification scheme.
Quality Rating:
Neutral NEUTRAL: See Quality Criteria Checklist below.
Research Purpose:

To carry out an economic evaluation of a randomized clinical trial in which drug treatment and non-pharmacological treatment were compared with respect to changes in major cardiovascular risk factors. 

Inclusion Criteria:
  • Male
  • 40 to 69 years of age
  • Obese (BMI >26 kg/m2)
  • Untreated DBP of 90 to 104mm Hg.
Exclusion Criteria:
  • Diabetes mellitus
  • Organ damage secondary to hypertension
  • Diseases that might have interfered with compliance and the interpretation of results.
Description of Study Protocol:

Recruitment

Screening after advertisement in newspaper.

Design

Randomized clinical trial. Six-week run-in period followed by randomization to either diet or drug treatment for one year.

Intervention

Random assignment to one of two groups:

  • Diet to reduce weight by more than or equal to 5%, restrict sodium to less than or equal to 95mmol per day; decrease alcohol intake if consuming more than or equal to 250g per week
  • Drug treatment of 50mg per day to 100mg per day of atenolol.

Statistical Analysis

  • Cost-effectiveness analyses: Treatment costs, saved costs of cardiovascular disease morbidity, divided by increase in life expectancy (both direct and indirect costs)
  • Sensitivity analyses (direct costs only)
  • Life years gained: Computer simulation model
  • Cost-benefit analyses of treatment and saved morbidity costs.

 

Data Collection Summary:

Timing of Measurements

Blood pressure and serum lipid concentrations assessed at run-in and after one year.

Dependent Variables

  • Change in DBP, total cholesterol, HDL and LDL cholesterol, triglycerides
  • Treatment cost
  • Cost-effectiveness per patient for diet and drug treatments
  • Cost-benefit analysis of diet and drug treatment
  • Life years gained
  • Willingness to pay.

Independent Variables

Assignment to diet or drug treatment group.

 

Description of Actual Data Sample:
  • Initial N: 64 men were recruited and 61 completed the study. N=31 in diet and N=30 in drug treatment group
  • Attrition (final N): Cost-benefit analysis; N=28 in diet and 25 in drug group, those who had completed questionnaire used to perform analyses
  • Age: aged 40 to 69 years
  • Ethnicity: Not reported.

Location

  • Centre for Health Economics, Stockholm School of Economics, Stockholm
  • Department of Medicine, Sahlgren's Hospital, Gothenberg University, Gothenberg, Sweden.

 

Summary of Results:

After 1 year, total body weight decreased by 7.6±3.1kg in diet group and increased by 0.9±2.3kg in drug treatment group. Sodium intake was reduced by 42±48mmol per day and 10±54mmol per day in the diet and drug groups, respectively. 

Variables (Change from pre-Tx to One Year)

Diet Group (N=31)

Drug Group (N=30)

Statistical Significance of Group Difference

DBP (mm Hg)

-3±6

-11±6

P<0.001

Total cholesterol (mmol per L)

-0.33±0.85

0.04±0.55

P=0.082

HDL (mmol per L)

0.9±0.37

-0.13±0.33

P<0.001

LDL (mmol per L) -0.32±0.68 -0.02±0.62 P=0.037
Triglycerides (mmol per L) -0.23±0.89 0.42±0.72 P=0.003

 Treatment cost per patient.

Cost, Swedish Crowns $

Diet Group

Drug Group

Difference

(Diet-drug)

Drugs

0

1,342

-1,342

Consultations

4,280

4,280

0

Dietitian

900

0

+900

Group meetings 130 0 +130
Travel 720 520 +200
Time 2,318 1,770 +548
Total Cost 8,348 7,912 +436

Cost-benefit analysis: Both treatments resulted in a loss compared to no treatment, but difference between diet and drug group very small.

Cost, Swedish Crowns $

Diet Group

Drug Group

Difference

(Diet/drug)

Willingness to pay (benefit)

5,556

5,448

+108

Costs:

 

 

 

Treatment

8,212

8,233

-21

Saved disease -1,142 -1,142 0
Total 7,070 7,091 -21
Benefits per Costs -1,514 -1,643 +129

Drug treatment was the preferred option in three of the five cost-effectiveness simulations. The cost-benefit analysis did not show any difference between the two groups.

Author Conclusion:

It is difficult to draw any definite conclusions about the cost-effectiveness of diet versus drug treatment from this study due to the lack of important knowledge regarding the effect of risk factor changes upon the incidence of CHD

When this study is combined with available data, it seems that non-pharmacological treatment (diet) used in a clinical setting is less cost-effective than anti-hypertensive drug treatment. 

Funding Source:
Government: National Corporation of Swedish Pharmacies, Swedish Council for Planning and Coordination of Research
Not-for-profit
0
Foundation associated with industry:
Reviewer Comments:

Small number of subjects; diet intervention not described in detail. Authors note that "the contradictory results of these simulations clearly demonstrate our lack of knowledge concerning important aspects of anti-hypertensive treatment." Authors also note that the interpretation of the results has to be related to the fact that it was a highly selected patient sample, based on obese men motivated for diet treatment.

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? ???
  5.1. In intervention study, were subjects, clinicians/practitioners, and investigators blinded to treatment group, as appropriate? ???
  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.) ???
  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? No
  6.1. In RCT or other intervention trial, were protocols described for all regimens studied? No
  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? 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? 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)? N/A
  8.5. Were adequate adjustments made for effects of confounding factors that might have affected the outcomes (e.g., multivariate analyses)? N/A
  8.6. Was clinical significance as well as statistical significance reported? ???
  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