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DM: Weight Management (2007)

Citation:

Vettor R, Serra R, Fabris R, Pagano C and Federspil G. Effect of sibutramine on weight management and metabolic control in type 2 diabetes: a meta-analysis of clinical studies. Diabetes Care 2005;28(4):942-949.

PubMed ID: 15793204
 
Study Design:
Meta-analysis or Systematic Review
Class:
M - Click here for explanation of classification scheme.
Quality Rating:
Positive POSITIVE: See Quality Criteria Checklist below.
Research Purpose:

The purpose was to determine the effect of sibutramine on weight loss and glycemic control in obese subjects with type 2 diabetes.

Inclusion Criteria:
  • randomized controlled clinical trials (blind, parallel or crossover)
  • diagnosis of type 2 diabetes
  • presence of overweight or obesity
  • minimum duration of treatment with sibutramine of at least 3 months
  • full publication in English
Exclusion Criteria:
  • abstracts of studies
Description of Study Protocol:

Literature Search:

  • electronic databases  searched included Cochrane library, Medline, EMBASE
  • reference lists of all relevant articles
  • authors also contacted Abbott Laboratories to identify unpublished data
  • key terms used: "sibutramine, obesity, diabetes, clinical trials"

Design: meta-analysis

Blinding used: not applicable

Intervention: sibutramine

Statistical Analysis

  • Hedges and Olkin mehods to determine effect size for each study; mean of a control group subtracted from mean of the experimental group and divided by pooled SD of both groups
  • degree of homogeneity or heterogeneity of dataset and X2 test also calculated
Data Collection Summary:

Timing of Measurements: trials lasted until 2004

Outcome Measures (Dependent Variables)

  • body weight
  • waist circumference
  • fasting blood glucose and serum insulin
  • HbA1c
  • fasting seru triglycerides
  • total, DLD- and HDL choleserol
  • systolic and diastolic blood pressure
  • heart rate

Independent Variables

  • sibutramine

Control Variables

 

Description of Actual Data Sample:

Initial N: 10 studies with total of 1093 subjects (552 sibutramine and 541 placebo)

Attrition (final N): not applicable

Age: mean age of sibutramine-treated subjects in all the studies was not given but described as "slightly lower than in the placebo group" the overall effect resulted in a significant difference between the two groups (P = 0.0078)

Ethnicity: not described

Other relevant demographics:

Anthropometrics:

Location: worldwide studies

 

Summary of Results:

 Data from eight studies were included in the meta-analysis.

Variables

Sibutramine Group

Measures and confidence intervals

Control group

Measures and confidence intervals

Overall Effect Size standard mean difference (95% CI)

Statistical Significance of Group Difference

Decrease in weight (kg)

5.533 ± 0.225

-0.900 ± 0.169

0.85 (95% CI 1.00-0.74)

P < 0.0001

Decrease in waist circumference (cm)

 5.320 ± 0.310

 -1.130 ± 0.160

0.67 (0.83-0.51)

 P < 0.0001

Statistically significant improvements with sibutramine treatment. Values are given as standard mean differences (units were not noted).

  • basal blood glucose showed a small decrease of 0.17  (95% CI 0.03-0.32; P=0.0187)
  • HbA1c decreased -0.28% (95% CI -0.13 to -0.42%; P=0.0002)
  • serum triglycerides -0.24 (95% CI -0.09 to -0.39; P=0.0024)
  • HDL cholesterol 0.20 (95% I 0.05-0.35; P=0.0087)
  • no clear evidence for an effect of sibutramine treatment on systolic blood pressure and a weak increase in diastolic blood pressure (0.22 95% CI 0.07-0.38; P=0.005)

Other Findings

 

Author Conclusion:
Sibutramine has a substantial effect on weight loss which may impart a considerable benefit on glycemic control and lipid profile.
Funding Source:
University/Hospital: University of Padua (Italy)
Reviewer Comments:
Quality Criteria Checklist: Review Articles
Relevance Questions
  1. Will the answer if true, have a direct bearing on the health of patients? Yes
  1. Will the answer if true, have a direct bearing on the health of patients? Yes
  2. Is the outcome or topic something that patients/clients/population groups would care about? Yes
  2. Is the outcome or topic something that patients/clients/population groups would care about? Yes
  3. Is the problem addressed in the review one that is relevant to dietetics practice? Yes
  3. Is the problem addressed in the review one that is relevant to dietetics practice? Yes
  4. Will the information, if true, require a change in practice? Yes
  4. Will the information, if true, require a change in practice? Yes
 
Validity Questions
  1. Was the question for the review clearly focused and appropriate? Yes
  1. Was the question for the review clearly focused and appropriate? Yes
  2. Was the search strategy used to locate relevant studies comprehensive? Were the databases searched and the search termsused described? Yes
  2. Was the search strategy used to locate relevant studies comprehensive? Were the databases searched and the search termsused described? Yes
  3. Were explicit methods used to select studies to include in the review? Were inclusion/exclusion criteria specified andappropriate? Wereselectionmethods unbiased? Yes
  3. Were explicit methods used to select studies to include in the review? Were inclusion/exclusion criteria specified andappropriate? Wereselectionmethods unbiased? Yes
  4. Was there an appraisal of the quality and validity of studies included in the review? Were appraisal methodsspecified,appropriate, andreproducible? Yes
  4. Was there an appraisal of the quality and validity of studies included in the review? Were appraisal methodsspecified,appropriate, andreproducible? Yes
  5. Were specific treatments/interventions/exposures described? Were treatments similar enough to be combined? Yes
  5. Were specific treatments/interventions/exposures described? Were treatments similar enough to be combined? Yes
  6. Was the outcome of interest clearly indicated? Were other potential harms and benefits considered? Yes
  6. Was the outcome of interest clearly indicated? Were other potential harms and benefits considered? Yes
  7. Were processes for data abstraction, synthesis, and analysis described? Were they applied consistently acrossstudies and groups? Was thereappropriate use of qualitative and/or quantitative synthesis? Was variation in findings among studies analyzed? Were heterogeneity issued considered? If data from studies were aggregated for meta-analysis, was the procedure described? Yes
  7. Were processes for data abstraction, synthesis, and analysis described? Were they applied consistently acrossstudies and groups? Was thereappropriate use of qualitative and/or quantitative synthesis? Was variation in findings among studies analyzed? Were heterogeneity issued considered? If data from studies were aggregated for meta-analysis, was the procedure described? Yes
  8. Are the results clearly presented in narrative and/or quantitative terms? If summary statistics are used, are levels ofsignificance and/or confidence intervals included? Yes
  8. Are the results clearly presented in narrative and/or quantitative terms? If summary statistics are used, are levels ofsignificance and/or confidence intervals included? Yes
  9. Are conclusions supported by results with biases and limitations taken into consideration? Are limitations ofthe review identified anddiscussed? No
  9. Are conclusions supported by results with biases and limitations taken into consideration? Are limitations ofthe review identified anddiscussed? No
  10. Was bias due to the review's funding or sponsorship unlikely? Yes
  10. Was bias due to the review's funding or sponsorship unlikely? Yes