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

Citation:

Sikand G, Kashyap ML, Yang I. Medical nutrition therapy lowers serum cholesterol and saves medication costs in men with hypercholesterolemia. J Am Diet Assoc. 1998; 98: 889-894.

PubMed ID: 9710659
 
Study Design:
Retrospective Cohort Study
Class:
B - Click here for explanation of classification scheme.
Quality Rating:
Neutral NEUTRAL: See Quality Criteria Checklist below.
Research Purpose:

This study was designed to evaluate whether medical nutrition therapy (MNT) administered by registered dietitians could lead to a beneficial clinical and cost outcome in men with hypercholesterolemia. Specific aims were to:

  • Determine whether medical nutrition therapy sessions provided by a registered dietitian led to a reduction in serum cholesterol and LDL-cholesterol (LDL-C)
  • Determine how many MNT sessions with a registered dietitian are ideal to achieve significant reductions in LDL-C
  • Determine if additional MNT sessions improve LDL-C outcome
  • Determine if the reduction in LDL-C with MNT is sufficient to obviate the need for lipid-lowering medications
  • Evaluate if the cost of treating patients with hypercholesterolemia with MNT is significantly less than the cost of treating them with lipid-lowering therapy.
Inclusion Criteria:

Medical records were reviewed for 95 subjects who had undergone a six- to eight-week NCEP step 1 dietary intervention in preparation for a cholesterol-lowering trial involving the use of an experimental lipid-lowering medication. Criteria included:

  • Outpatient
  • Primary diagnosis of hypercholesterolemia
  • Previously met NCEP eligibility criteria for initiating cholesterol-lowering drug therapy (LDL-C greater than or equal to 4.1mmol per L with two or more CHD risk factors)
  • Not taking cholesterol-lowering medications
  • Between the ages of 21 and 75 years
  • Had two to four visits with a dietitian over six to eight weeks.
Exclusion Criteria:

Patients lacking required information were excluded from the study.

Description of Study Protocol:
  • Recruitment: Of charts of 95 men reviewed, 21 were eliminated for incomplete information
  • Design: Retrospective cohort study. Charts were reviewed and subjects placed in groups of two, three or four visits with a registered dietitian. Analysis was done on relationship and visits and lowering of cholesterol, and associated costs.
  • Intervention: MNT by a registered dietitian.

Statistical Analysis

  • A two-tailed paired T-test was conduction to examine within-group changes for all subjects in total cholesterol, LDL-C, triglycerides, HDL-C, and body mass index (BMI)
  • Analysis of covariance was used to measure the relationship between the number of dietitian intervention visits and the resultant LDL-C level, adjusted for age and baseline LDL-C
  • The costs of lipid-lowering drugs were derived using the medical care component of the Consumer Price Index, and all cost calculations include a proportional 80% use of statin therapy and 20% use of niacin therapy.

 

Data Collection Summary:

Timing of Measurements

This review uses baseline and visit at six to eight weeks, original measurement dates not specified here.

Dependent Variables

  • Total cholesterol
  • LDL-C
  • Triglycerides
  • HDL-C
  • Body mass index.

Independent Variables

MNT visits by an RD; subjects placed in groups of two, three or four visits with a registered dietitian.

Control Variables

  • Age
  • Baseline LDL-C.
Description of Actual Data Sample:
  • Initial N: 95 men
  • Attrition (final N): 74 men had complete information and were picked for review
  • Age: 32 to 75 years, mean 60.8±9.8 years
  • Location: Department of Veterans Affairs Medical Center, Long Beach, CA.

 

Summary of Results:

 

Pre- and post-treatment values and changes in plasma lipids, body mass and lipid drug eligibility in 74 male veterans.

Variable Group

Mean Pre-Treatment Group

 

Mean Post-treatment Values

Mean Actual Change Value

Mean Actual Change %

Total cholesterol (mmol per L)

 

 

 

 

   All subjects

7.02±0.10

6.100.08

-0.94±0.09

-13.4

   Two visits (N=29)

7.07±0.21

6.27±0.14

-0.82±0.18

-11.6

   Three visits (N=32)

6.99±0.12

6.06±0.11

-0.92±0.12

-13.2

   Four visits (N=12)

7.07±0.18

5.82±0.14

-1.32±0.13

-18.6

LDL-C (mmol per L)

 

 

 

 

   All subjects

4.93±0.08

4.18±0.07

-0.05±0.02

-14.2

   Two visits (N=29)

4.86±0.16

4.28±0.11

-0.09±0.03

-12.1

   Three visits (N=32)

4.97±0.11

4.16±0.09

-0.04±0.04

-15.7

   Four visits (N=12)

5.04±0.19

3.95±0.14

-0.09±0.08

-21.9

HDL-C (mmol per L)

 

 

 

 

   All subjects

1.18±0.03

1.11±0.03

-0.05±0.02

-4.4

   Two visits (N=29)

1.17±0.04

1.09±0.04

-0.09±0.03

-4.4

   Three visits (N=32)

1.17±0.05

1.12±0.04

-.04±0.04

-3.3

   Four visits (N=12)

1.22±0.10

1.14±0.06

-0.09±0.08

-7.1

Triglyceride (mmol per L)

 

 

 

 

   All subjects

1.97±0.11

1.75±0.11

-2.22±0.87

-10.8

   Two visits (N=29)

2.18±0.20

1.9±0.18

-0.28±1.05

-12.4

   Three visits (N=32)

1.88±0.14

1.69±0.17

-0.14±0.78

-7.4

   Four visits (N=12)

1.72±0.16

1.54±0.18

-0.29±0.61

-16.3

Total cholesterol/high density lipoprotein cholesterol: All subjects

6.31±0.19

5.72±0.15

-0.59±0.14

-9.4

LDL-C/HDL-C: All subjects

4.46±0.15

3.92±0.11

-0.54±0.11

-12.1

Body mass index: All subjects

26.9±0.5

26.8±0.5

-0.1±0.52

0.4

Patients needing lipid-lowering drugs

 

 

 

 

   All subjects

67

33

-34

-51

   Two visits (N=29)

25

15

-10

-40

   Three visits (N=32)

31

14

-17

-55

   Four visits (N=12)

11

4

-7

-64

Estimated annualized cost savings of MNT vs. statin and niacin therapy in 74 male veterans.

Cost Variable
Cost (in 1995 Dollars)
Alternative A: MNT
 
Cost of initiating MNT for 74 patients for seven weeks (three RD visits of 50 minutes each)
$12,210.00
Cost of ongoing MNT for seven patients not eligible for drug therapy (two follow-up RD visits over remaining 45 weeks of 50 minutes each)
$770.00
Cost of ongoing MNT for 34 patients averted from drug therapy (two follow-up RD visits over remaining 45 weeks of 50 minutes each)
$3,740.00
Total cost of MNT over one year (initiating and ongoing: Five dietitian visits equals 250 minutes) (A)
$16,720.00
Alternative B: Cost of lipid drug therapy averted as a consequence of MNT
 
Cost of statin therapy, including monitoring, averted in 27 patients (80%) in one year
$71,511.95
Cost of niacin terapy averted in seven patients (20%) in one year
$5,769.75
Total cost of lipid drug therapy, including monitoring, averted in one year in 34 patients (B)
$77,281.68
Annualized cost savings of MNT vs. lipid drug therapy (B - A)
$60,561.68
Cost-Benefit ratio of MNT: Lipid drug therapy (including monitoring) (B/A)
1:4.28

Other Findings

Medical nutrition therapy lowered total serum cholesterol levels 13% (P<0.0001), LDL-C 11% (P<0.05), and HDL-C 4% (P<0.05).

Total dietitian intervention time was 144±21 minutes (range 120 to 180 minutes) in 2.8±0.7 sessions (range two to four) during 6.8±0.7 weeks of medical nutrition therapy (range six to eight weeks). 

Results showed a marginal difference between the number of dietitian visits and change in LDL-C (F=2.6, P<0.084).

However, the magnitude of LDL-C reduction was significantly higher with four dietitian visits (180 minutes) than with two visits (120 minutes) (21.9% vs. 12.1%, P=0.027).

Lipid drug eligibility was obviated in 34 of 67 (51%) subjects per the National Cholesterol Treatment Program guidelines algorithm.

The estimated annualized cost savings from the avoidance of lipid medications was $60,561.68.

Cost-effectiveness ratios varied from 4.66 to 7.74 for high-intensity care and 5.52 to 9.90 for moderate-intensity care.

The cost-effectiveness ratio expressed as dollar cost per unit of change in LDL-C improved as the intensity of dietitian intervention increased from two to four visits, despite the incremental dietitian changes.

 

 
Author Conclusion:

Data confirmed that individualized medical nutrition therapy provided by registered dietitians leads to significant reduction in total cholesterol (P<0.0001), LDL-C (P<0.0001) and triglycerides (P<0.05) levels.

For each dollar spent on medical nutrition therapy, a cost savings of $4.28 was noted.

Funding Source:
University/Hospital: University of Pittsburgh School of Medicine
Reviewer Comments:

Authors note that projected cost savings must allow for follow-up RD intervention and allowed for two additional visits per year, which "seemed reasonable," although there is no evidence to support this.

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? Yes
  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? 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? 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? 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? 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? 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? ???
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