EFFECTIVENESS OF PRIMARY CARE-RELEVANT TREATMENTS FOR OBESITY IN ADULTS: A

SYSTEMATIC EVIDENCE REVIEW FOR THE U.S PREVENTIVE SERVICES

LEBLANC ES, O’CONNOR E, WHITLOCK EP, PATNODE CD, KAPKA T ANN INTERN MED. 2011;155:434-4

FUNDING: AGENCY FOR HEALTHCARE RESEARCH AND QUALITY

Terry SonMercer UniversityOctober 28, 2011

OBJECTIVE

To summarize the effectiveness and harms of primary care-relevant weight-loss interventions for overweight and obese adults

BACKGROUND

Obesity (BMI > 30 kg/m2) is high in the U.S. exceeding 30% in most age and sex-specific groups

2007-2008—32% men and 36% women were obese Prevalence of obesity and of overweight have

increased by 134% and 48%, respectively since 1976-1980

http://resources0.news.com.au/images/2011/03/30/1226030/4795

BACKGROUND

Obesity is associated with: increased mortality, especially in adults <65 years Coronary heart disease Type 2 diabetes Certain types of cancer

http://medicineworld.org/news/news-archives/438941683-April-15-2009.html

BACKGROUND

In 2003, the U.S. Preventive Services Task Force (USPSTF) recommended that clinicians:

Screen all adults for obesity and Offer intensive counseling and behavioral

interventions

http://neuroscene.com/wp-content/uploads/2011/08/obesity.jpg

BACKGROUND

According USPSTF: Insufficient evidence to recommend for or

against moderate or low-intensity counseling together with behavior interventions to promote sustained weight loss in obese adults

Evidence was insufficient to recommend for or against counseling of any intensity and/or behavioral interventions to promote sustained weight loss in over-weight adults

BACKGROUND

The study did a systematic review to help update the recommendations

Developed an analytic framework with 4 key questions

KQ1 Asked whether primary care screening programs to identify obesity or over-weight in adults improved health or physiologic outcomes or resulted in weight loss.

KQ2 Asked whether primary care weight-loss interventions (behaviorally based with or without pharmacologic adjuncts) improved health outcomes.

KQ3 Asked whether primary care weight-loss interventions (behaviorally based with or without pharmacologic adjuncts) resulted in short-term (12 to 18 months) or long term (>18 months) weight loss, with or without improved physiologic measures

KQ4 Asked whether primary care weight-loss interventions (behaviorally based with or without pharmacologic adjuncts) caused harm or adverse events

DESIGN

6498 abstracts reviewed

648 articles reviewed against pre-specified inclusion and exclusion criteria

Included trials were appraised as good, fair, or poor quality

DESIGN

Key Questions 1-3 Randomized controlled clinical trials with

interventions focused on weight loss in adults ≥ 18 years in settings relevant to primary care settings

Key Question 4 Large cohort or case-control studies Large event monitoring Systematic evidence reviews of RCTs (randomized

controlled trials) Did not require 12 months of follow-up

RESULTS

Key Question 1: Screening for Obesity/Overweight

No trials identified in comparing screening vs no screening for adult obesity

RESULTS

Behavioral trial participants: Mean BMI 25 –39 kg/m² 34-70 years-old 60% female <40% non-white

Orlistat trial participants: 66% female <12% non-white

Metformin trial participants: Only one reported ethnicity; 45.3% non-white

Baseline BMI across all trials: 31.9 kg/m² 55% of behavioral trials and 57% orlistat trials had

clinical or subclinical cardiovascular risk factors Metformin trials examined participants with diabetes risk

factors

Patient Characteristics for KQs 2&3

RESULTS

Key Questions 2 & 3: Benefits of Weight-Loss Interventions

58 trials

(identified benefits of weight- loss interventions)

38 trials(13,495

P*)

18 trials(11,256P*)

3 trials(2,652 P*)

BI** Orlistat + BI**

Metformin + BI**

* P = Participants**BI = Behavioral interventions

k1/3 of trials: not included in a weight-loss meta-analysis due to missing information

k k

RESULTS

Key Question 4: Harms of Weight-Loss Interventions

Behavioral Intervention Studies: Total participants: not specified 10 studies used (not specified) Weight loss reduced total or hip bone mineral density in 3

fair-to good-quality trials

Orlistat (+ Behavioral Interventions): Total participants: 12, 174 18 RCTs included from KQs2 &3 5 additional studies not included in KQs 2 &3

Metformin (+ Behavioral Interventions): Total participants : 2,712 4 trials included (3 from KQs 2&3 and 1 additional RCT)

AUTHORS’ CONCLUSION

No direct evidence on benefits and harms of primary care-based obesity screening

Behavioral weight-loss interventions with or without orlistat or metformin yielded clinically meaningful weight loss

COMMENTARY

Strengths Contained analytic framework with 4 key questions Included meta-analysis Included sufficient trials for meta-analysis of behavioral

interventions on weight change data

Limitations: Few studies reported health outcomes Behaviorally based treatments were heterogeneous and specific

elements were not well-described Medication trials were inadequately powered for rare adverse

effects Meta-analysis were not performed on some studies Did not specifically define behavioral interventions Limited good quality trials

COMMENTARY

Long-term weight and health outcomes data were lacking and should be studied

Research should clarify which benefits are derived specifically from weight loss itself or from behavioral mediators, such as physical activity or dietary changes

Weight loss of 6.6 lbs in 12-18 months may be clinically significant in pre-diabetes patients Caution: Orlistat and metformin may cause GI adverse

events Behavioral intervention treatments were safer

A closer look at classification of recommendations and level of evidenceCLASS IIa

Benefit >> RiskAdditional studies with focused objectives needed It is REASONABLE to perform procedure/administer treatment

CLASS IIbBenefit ≥ risk Additional studies with broad objectives

needed; additional registry data would be helpful

 Procedure/TreatmentMAY BE CONSIDERED

LEVEL AMultiple populations evaluated

Data derived from MULTIPLE randomized clinical trials or META-ANALYSES

Recommendation in favor of treatment or procedure being useful/effectiveSome conflicting evidence from multiple randomized trials or meta-analyses

Recommendation’s usefulness/efficacy less well establishedGreater conflicting evidence from multiple randomized trials or meta-analyses

LEVEL BLimited populations evaluated

Data derived from a SINGLE randomized trial or NONRANDOMIZED studies

Recommendation in favor of treatment or procedure being useful/effective Some conflicting evidence from a single randomized trial or nonrandomized studies

Recommendation’s usefulness/efficacy less well established Greater conflicting evidence from a single randomized trial or nonrandomized studies

LEVEL CVery limited populations evaluated

Only consensus opinion of experts, case studies, or standard or care

Recommendation in favor of treatment or procedure being useful/effective Only diverging expert opinion, case studies, or standard of care

Recommendation’s usefulness/efficacy less well established Only diverging expert opinion, case studies, or standard of care

Recommendation in favor of treatment or procedure being useful/effective

Some conflicting evidence from multiple randomized trials or meta-analyses

EFFECTIVENESS OF PRIMARY CARE-RELEVANT TREATMENTS FOR OBESITY IN ADULTS: A

SYSTEMATIC EVIDENCE REVIEW FOR THE U.S PREVENTIVE SERVICES

LEBLANC ES, O’CONNOR E, WHITLOCK EP, PATNODE CD, KAPKA T ANN INTERN MED. 2011;155:434-4

FUNDING: AGENCY FOR HEALTHCARE RESEARCH AND QUALITY

Terry SonMercer UniversityOctober 28, 2011