MNT: Weight Management (2015)


Wolf AM, Siadaty M, Yaeger B, Conaway MR, Crowther JQ, Nadler JL, Bovbjerg VE. Effects of lifestyle intervention on health care costs: Improving Control with Activity and Nutrition (ICAN). J Am Diet Assoc. 2007; 107: 1365-1373.

PubMed ID: 17659904
Study Design:
Randomized Controlled Trial
A - Click here for explanation of classification scheme.
Quality Rating:
Positive POSITIVE: See Quality Criteria Checklist below.
Research Purpose:

To evaluate the within-trial program costs and economic outcomes associated with a one-year lifestyle intervention led by a Registered Dietitian (RD) lifestyle case manager.

Inclusion Criteria:
  • Patients with type 2 diabetes
  • Diabetes medication use
  • Body mass index (BMI) of 27 kg/m2 or more
  • Age 20 years or older
  • Ability to comprehend English
  • Membership in Southern Health Services health plan as primary health insurance.
Exclusion Criteria:
  • Patients who were pregnant
  • Patients who had cognitive limitations or medical reasons precluding dietary and physical activity modifications
  • Patients who did not give informed consent. 
Description of Study Protocol:


Not discussed. Participants were health plan members.


12-month randomized controlled trial comparing lifestyle case management to usual care, conducted from 2001 to 2003.

Blinding Used 

Study personnel were blinded to allocation schedule until assignment.


  • Lifestyle case management: One RD case manager met with participants individually and in groups, and by phone for assessment, goal setting, education and referrals to community resources. Individual sessions occurred six times throughout the year, totaling four hours. Goals were tailored but based on national dietary recommendations for people with type 2 diabetes and obesity. Participants also attended six one-hour small group sessions (10 or more people per group) developed to provide the majority of education regarding diet and physical activity for improved glucose control and weight loss. Participants were given the LEARN (Lifestyle, Exercise, Attitudes, Relationships, Nutrition) manual.
  • Usual care: Received educational material only.

Statistical Analysis

  • The "four equation model" of Duan and colleagues was used to model total costs 
  • Logit link and bias corrected and accelerated nonparametric bootstrap was used for obtaining standard errors.


Data Collection Summary:

Timing of Measurements

12-month study.

Dependent Variables

The primary outcomes were:

  • Health care utilization during the year of trial
  • Health plan costs during the year of trial
  • Medical costs reimbursed by the participant's primary insurance company 
  • Pharmaceutical health care costs reimbursed by the participant's primary insurance company. 

Independent Variables

  • RD case management group: Included individual and group education, support and referrals by RDs
  • Usual-care group: Received educational material.



Description of Actual Data Sample:
  • Initial N: 147 randomly assigned to usual care (N=74) or case management (N=73). Three patients withdrew before baseline assessment.
  • Attrition (final N): 144 (87 female, 57 male); 72 in each group for intent-to-treat analysis.


  • Usual care group: 53.4±8.0 years
  • Case management group: 53.3±8.6 years.


79.5 % white (114 participants).


Groups were similar in demographic and clinical measures at baseline.

  • BMI:
    • Usual care group: 37.5±6.4
    • Case management group: 37.6±7.7
  • Waist circumference (cm)
    • Usual care group: 118.1±16.5
    • Case management group: 116.8±15.5.


Charlottesville, Virginia, US.


Summary of Results:


Mean and Median Health Care Costs and Health Care Utilization by Study Group During the Time Period of the ICAN Intervention

Type of Service                                                Usual Care Group                    Case-management Group 95% CI or P-value for Absolute Cost Difference
Medical Care      
Mean costs 8,536±3,538 5,220±5784 P<0.05
Inpatient mean cost 13,491±3,241  8,477±10,098  P=0.35, NS 
Inpatient utilization 16   2 P<0.001 
Outpatient mean cost 3,811±4,612  3,402±2,481  P=0.51, NS 
Outpatient utilization 1,333  1,334  P=0.50, NS 
Emergency room mean cost 862±1,488  849±662  P=0.97, NS 
Emergency room utilization 47   65 Not stated
Procedures mean cost 2,880±4,646 1,409±1,097 P=0.15, NS
Procedures utilization 17 14 Not stated
Pharmaceutical Care      
Mean cost 2,832±1,589 2,593±1,846

-870 to $280, NS

Change in number of medicines -0.3 meds/day -0.9 meds/day P<0.01
Total Health Care      
Mean cost 11,406±13,892 7,495±5,763 P<0.05

Other Findings

  • Net cost of the intervention was $328 per person per year
  • After incorporating program costs, mean health plan costs were $3,586 (95% confidence interval: -$8,036, -$25, P<0.05) lower in the case management group compared with the usual care group. The difference was driven by group differences in medical, but not pharmaceutical, costs, with fewer inpatient admissions and costs among case management compared with usual care (admission prevalence: 2.8% vs. 22.5% respectively, P<0.001). 
Author Conclusion:

Registered Dietitian-led lifestyle case-management intervention to usual medical care did not increase health care costs and suggested modest cost savings among obese patient with type 2 diabetes.

Funding Source:
Government: NIDDK
University/Hospital: University of Virginia
Reviewer Comments:

The author stated: "We remain cautious in declaring a cost saving within this pilot project because of the relatively small sample size for an economic evaluation coupled with large confidence intervals. Larger trials are needed to verify our results." Authors note the following limitations:

  • Small sample size for economic evaluation
  • Restriction to insured participants
  • Short follow-up
  • Inherent limitations of administrative claims data.
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? 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? 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? Yes
  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? 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? 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)? Yes
  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