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

Citation:

Sikand G, Kashyap ML, Wong ND, Hsu JC. Dietitian intervention improves lipid values and saves medication costs in men with combined hyperlipidemia and a history of niacin noncompliance. J Am Diet Assoc. 2000; 100: 218-224.

PubMed ID: 10670395
 
Study Design:
Retrospective Cohort Study
Class:
B - Click here for explanation of classification scheme.
Quality Rating:
Positive POSITIVE: See Quality Criteria Checklist below.
Research Purpose:
  • To determine whether medical nutrition therapy (MNT) administered by a registered dietitian leads to a reduction in levels of serum cholesterol, low-density lipoprotein cholesterol (LDL-C) and triglycerides
  • To determine if eight weeks of MNT is sufficient to obviate the need for antihypertensive medication
  • To evaluate if the cost of managing patients for one year with MNT would be significantly less than the cost of lipid-lowering medications.

 

Inclusion Criteria:

This study was a secondary analysis. Initial criteria for inclusion in the study to evaluate the efficacy of pravastatin, a 3-hydroxy-3-methylglutaryl coenzyme A (HMG CoA) reductase inhibitor, which included all subjects being asked to undergo eight weeks of dietitian intervention while following an NCEP step one diet as a dietary lead-in phase to qualify for statin therapy.

Criteria included:

  • Outpatient status (study through Department of Veterans Affairs Medical Center Lipid Research Clinic)
  • Diagnosis of combined hyperlipidemia defined as having cholesterol level of 6.2mmol per L or greater, and triglyceride level of 1.7mmol per L to 9.0mmol per L
  • Previously met NCEP eligibility criteria for initiation of anti-hyperlipidemic medications (LDL-C greater than or equal to 4.1mmol per L with two or more risk factors for coronary heart disease)
  • Not taking anti-hypertensive medications
  • Less than 140% of desirable body weight
  • Between the ages of 21 and 75 years
  • Had two to four individualized dietitian visits over an eight-week period
  • History of self-reported niacin non-compliance.
Exclusion Criteria:

Not specified.

Description of Study Protocol:

Recruitment

Patients at the Department of Veterans Affairs Medical Center in Long Beach, California who were "niacin failures" (self-reported non-compliance) with a previously prescribed niacin regimen. Subjects were screened by a telephone interview and invited to the lipid research center between May, 1992 and August, 1993 to qualify for participation in a clinical trial to evaluate the efficacy of pravastatin.

Design

Retrospective cohort and secondary analysis. Baseline lipid values obtained from VA computerized laboratory data records and patient records. Final lipid values obtained at week six or seven of the dietary lead-in phase.

Intervention

Dietitian visits occurred as follows: 

  • Visit one at week zero (70 minutes)
  • Visit two at week four (70 minutes)
  • Visit three at week six (30 minutes)
  • Visit four at week seven (30 minutes).

Statistical Analysis 

  • A two-tailed paired T-test was conducted to examine within-group changes before and after dietitian intervention in levels of total cholesterol, LDL-C, triglycerides, HDL-C and body mass index
  • Total cholesterol reduction was evaluated to determine changes in risk for coronary artery disease according to NCEP criteria
  • Cost analysis was done, including a sensitivity analysis to prevent overly optimistic results by including the cost of a baseline MNT visit for the 30 subjects who chose not to participate in the study but received the initial dietitian intervention.

 

Data Collection Summary:

Timing of Measurements

Lipid values collected at baseline and at week six or seven. Dietitian visits occurred as follows: 

  • Visit one at week zero
  • Visit two at week four
  • Visit three at week six
  • Visit four at week seven.

Dependent Variables

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

Independent Variables

Dietitian visits occurred as follows: 

  • Visit one at week zero (70 minutes)
  • Visit two at week four (70 minutes)
  • Visit three at week six (30 minutes)
  • Visit four at week seven (30 minutes).

Control Variables

  • Age
  • Number of treatment visits.

 

Description of Actual Data Sample:
  • Initial N: Retrospective chart review of 73 men
  • Attrition (final N): 43 had complete information for data analysis
  • Age: 33 to 75, mean = 60.7±10.1 years
  • Ethnicity: Not specified
  • Other relevant demographics: All participants were male
  • Location: Long Beach, CA Department of Veteran's Affairs Medical Center Lipid Research Clinic.

 

Summary of Results:

Pre-treatment and post-treatment values and changes in plasma lipid levels, body mass index and statin therapy in 43 male volunteers in 6.5±2.0 weeks. 

Variable and Group

Mean Pre-Treatment Values

Mean Post-treatment Values

Mean Actual Change Value

Mean Actual Change %

Total cholesterol (mmol/L)

 

     
   All subjects (N=43)  6.7±0.9  6.0±0.9  -0.75±0.09  -11%
   Two visits (N=17)  6.8±0.9  6.0±1.0  -0.78±0.13  -11%
   Three visits (N=23)  6.7±0.9  6.0±0.9  -0.65±0.12  -9%
   Four visits (N=3)  7.2±1.1  6.0±1.3  -1.15±0.72  -15%
LDL-cholesterol (mmol per L)        
   All subjects (N=43)  4.4±0.8  3.8±0.9  -0.41±0.10  -9%
   Two visits (N=17)  4.5±0.9  3.8±0.9  -0.54±0.15  -12%
   Three visits (N=23)  4.5±0.6  3.9±0.9  -0.28±0.14  -6%
   Four visits (N=3)  3.6  3.5±0.7  -0.36  -10%
HDL-cholesterol (mmol per L)        
   All subjects (N=43)  0.9±0.2  0.9±0.2  0.02±0.02  4%
   Two visits (N=17)  0.9±0.2  0.9±0.2  0.005±0.04  2%
   Three visits (N=23)  0.8±0.2  08±0.2  0.03±0.03  5%
   Four visits (N=3)  0.9±0.1  0.9±0.2  0.03±0.05  2%
Triglycerides (mmol per L)        
   All subjects (N=43)  4.2±2.1  3.0±1.6  -1.1±0.2  -22%
   Two visits (N=17)  4.0±2.1  2.9±1.5  -1.1±0.4  -22%
   Three visits (N=23)  4.1±2.1  3.0±1.7  -1.1±0.3  -21%
   Four visits (N=3)  5.2±1.9  3.6±1.8  -1.5±1.0  -27%

Body Mass Index

 

 

 

 

   All subjects (N=43)  29.9±3.4  29.2±3.2  -0.7±0.1  -2%
   Two visits (N=17)  30.3±3.8  29.5±3.4  -0.8±0.2  -2%
   Three visits (N=23)  29.5±3.4  29.0±3.3  -0.5±0.1  -1%
   Four visits (N=3)  30.6±2.6  29.3±1.9  -1.2±0.4  -5%
Patients needing anti-hyperlipidemic medications        
   All subjects (N=43)  30  15  -15  -50%
   Two visits (N=17)  12  5  -7  -58%
   Three visits (N=23)  16  9  -7  -44%

    Four visits (N=3)

 2

 1

 -1

 -50%

 

Cost Variable
Cost (In 1996 Dollars)
Cost of MNT interventions for one year [Initiating MNT cost for 43 patients during first eight weeks ($175 per patient, for three visits of 70 minutes, 70 minutes, 30 minutes each)] (a).
 $7,525.00
Ongoing MNT costs for 13 non-drug eligible patients for remaining 44 weeks (four follow-up dietitian visits of 30 minutes each at $140 per patient) (b).
 $1,820.00
Ongoing MNT cost for 15 patients for whom statin therapy was averted for the remaining 44 weeks (four follow-up dietitian visits of 30 minute each at $140 per patient) (c ).
$2,100.00
Actual total cost of MNT for one year (a+b+c=D).
$11,445.00
Sensitivity analysis (baseline MNT cost for 30 patients who chose to not participate); baseline MNT costs for 30 dropouts (initial visit of 70 minutes at $70 per patient (e).
$2,100.00
Conservative total cost of MNT for one year (D+e=F).
$13,545.00
Consequence of MNT intervention (statin therapy cost, including monitoring, averted by MNT for one year). [Total cost of statin therapy (including monitoring) averted for one year in 15 patients at $2,732.94 per patient=G].
$40,994.10
Conservative net benefit (cost savings) from MNT as a result of averted statin therapy (G-D=H).
$29,549.10
Actual net benefit (cost savings) per patient as a result of averted statin therapy (I per number of study patients).
$687.19
Conservative net benefit (cost savings) from MNT as a result of averted statin therapy (G-F=I).
$27,449.10
Conservative net benefit (cost savings) per patient as a result of averted statin therapy (I per number of study patients).
$638.35
Actual cost/benefit ratio (G/D).
1:3.58
Conservative cost/benefit ratio (G/F).
1:3.03
 

Other Findings

Total dietitian intervention time was 169±19 minutes in 2.7±0.6 sessions (range two to four sessions) during 6.5±2.2 weeks of MNT (range four to eight weeks).

MNT lowered levels of total cholesterol 11% (P<0.001); LDL-C, 9% (P<0.001); triglycerides, 22% (P<0.0001); and BMI, 2% (P<0.0001).  MNT raised HDL-C 4%.

After dietitian intervention, only 15 of 30 eligible patients required anti-hypertensive medications, which led to an annual cost savings of $27,449.10, or $638.35 per patient.

A cost savings of $3.03 in statin therapy was realized for each dollar spent on MNT.

Author Conclusion:

Dietitian intervention (an average of three individualized dietitian visits of one hour each over an eight-week period) resulted in positive short-term clinical outcomes and cost savings of lipid-lowering medications and related monitoring costs.

As a result of significant reduction in lipid values, 15 fewer patients (of the 30 eligible patients) required anti-hyperlipidemic medications after dietitian intervention.

A net cost benefit of of $687.19 per patient was realized. The cost-benefit ratio shows that for each dollar spent on MNT, $3.58 was averted in statin therapy. Sensitivity analysis resulted in a more conservative net cost benefit of $638.35 per patient, and the cost-benefit ratio shows that for each dollar spent on MNT, $3.03 was averted in statin therapy.

Funding Source:
Not-for-profit
0
Foundation associated with industry:
Reviewer Comments:

The longer-term estimates (beyond the eight weeks) did not clearly indicate their evidence basis.

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? ???
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