Physician weight loss advice and patient weight loss behavior change: a literature review and meta-analysis of survey data

CRD summary

The review concluded that primary care provider advice on weight loss appeared to have a significant impact on patient attempts to change behaviours related to their weight. The authors’ conclusions appear overstated given the limitations of the evidence and reliance on survey data and may not be reliable.

Authors' objectives

To determine whether primary care provider counselling enhances patient engagement in weight reduction efforts.

Searching

Seven databases including PubMed, PsycINFO and The Cochrane Library were searched to November 2011 for articles published in English. Search terms were reported. Reference lists of retrieved articles were scanned.

Study selection

Eligible studies evaluated patient impressions of primary care provider weight loss advice or counselling on overweight status assessed through survey or observational data. Primary care provider could include a physician, nurse practitioner or physician assistant. Studies of patients of all weights were eligible. Data could be self-reported or via chart documented information.

Interventions by primary care providers included specific advice and information on weight loss and use of motivational interviewing to promote weight loss. Data for outcome measures were collected using a variety of published and unpublished surveys and questionnaires; some studies used the same national datasets and local datasets were also used. Most of the included studies were conducted in USA with one study each conducted in UK, Germany and Switzerland. Studies included overweight and/or obese patients or all weights including normal weight. Some patients had comorbidities such as arthritis, asthma, cardiovascular disease and diabetes.

The authors did not state how many reviewers selected studies for inclusion.

Assessment of study quality

Two reviewers assessed study quality using published criteria for methods of sampling, measurement, analysis, interpretation of results and other issues. Disagreements were resolved through discussion.

Data extraction

Two reviewers independently extracted data on patient weight loss attempts to enable calculation of odds ratios and 95% confidence intervals. Odds ratios were calculated using the odds of an event occurring in an exposed population divided by the odds of an event occurring in an unexposed population. Disagreements were resolved through discussion. Study authors were contacted for missing data where necessary.

Methods of synthesis

Pooled odds ratios and 95% CIs were calculated using a random-effects meta-analysis. Statistical heterogeneity was assessed using the Q and Ι² statistics. Sensitivity analyses removed studies with different populations (such as children) and those with outlying results to assess their effect on the analysis. Moderator analyses were undertaken to determine the impact of study characteristics on the analysis including obese patients versus mixed samples, adults versus children, surveyed by telephone versus in-person survey, data published before 1998 versus after 1998 and national versus local survey data. Studies that could not be included in the meta-analysis were described narratively.

Results of the review

Thirty-two observational studies were included in the review but only 12 were included in the meta-analysis (207,226 participants). The studies in the meta-analysis were reported to be of satisfactory quality.

The meta-analysis reported a significant impact of weight loss advice on efforts at weight loss (OR 3.85, 95% CI 2.71 to 5.49; 12 studies). However there was significant statistical heterogeneity for this analysis (Ι²=98.76%). The results of the sensitivity analyses were similar to the overall analysis. The moderator analyses reported a greater effect of weight loss advice in adults versus children and in patients who were surveyed by telephone compared to those surveyed in person. There were no significant differences in the effectiveness of advice in studies using obese patients only versus mixed samples.

The narrative synthesis reported significant actual weight loss by patients associated with primary care provided advice (seven studies). Other narrative results relating to patient stage of change, patient weight maintenance attempt and specific behaviour changes were reported.

Authors' conclusions

Primary care provider advice on weight loss appeared to have a significant impact on patient attempts to change behaviours related to their weight.

CRD commentary

The review question and inclusion criteria were broadly stated. Several relevant sources were searched. The restriction to studies in English means some data may have been missed. Study quality was assessed but results for individual studies were not reported and this made it difficult to independently comment on the evidence presented. Appropriate methods to reduce reviewer error and bias were used for quality assessment and data extraction but it was unclear whether similar methods were used for the selection of studies.

The primary outcome was weight loss attempt but this outcome may not result in actual behaviour change or weight loss.The more reliable outcome of the effect on actual weight loss was described narratively in a small subset of studies. All data were derived from surveys and these are prone to multiple potential biases and cannot determine the direction of causation of an effect. Several studies used the same survey data which precluded them being included in the meta-analysis. Combining these data in a meta-analysis may not have been appropriate given the substantial statistical heterogeneity (I²=98.76%) and variations between studies; therefore, the summary estimates should be interpreted with caution. Having found significant statistical heterogeneity, the authors explored potential reasons for this but some of the moderator analyses included only a small subset of studies.

The authors’ conclusions and recommendations appear overstated given the limitations of the evidence and reliance on survey data and may not be reliable.

Implications of the review for practice and research

Practice: The authors stated that primary care providers should address weight loss with their overweight and obese patients. Policy makers should recognise the primary care provider’s need for additional time and training in advising their patients as well as improvements in reimbursement and provision of tools such as dieticians. Primary care providers need to recognise their influence when advising their patients about their weight.

Research: The authors stated a need for further studies and interventions to clarify the role of primary care providers and to overcome barriers to provider self-efficacy relating to counselling during the clinic visit.

Funding

Not stated.

Bibliographic details

Rose SA, Poynter PS, Anderson JW, Noar SM, Conigliaro J. Physician weight loss advice and patient weight loss behavior change: a literature review and meta-analysis of survey data. International Journal of Obesity 2013; 37(1): 118-128. [PubMed: 22450855]

Original Paper URL

http://www.nature.com/ijo/journal/v37/n1/full/ijo201224a.html

Indexing Status

Subject indexing assigned by NLM

MeSH

Counseling; Diet, Reducing; Female; Health Behavior; Health Promotion /methods; Humans; Male; Obesity /epidemiology /prevention & control; Odds Ratio; Patient Compliance /statistics & numerical data; Physician's Role; Physician-Patient Relations; United States /epidemiology; Weight Loss

AccessionNumber

12013007313

Database entry date

26/09/2013

Record Status

This is a critical abstract of a systematic review that meets the criteria for inclusion on DARE. Each critical abstract contains a brief summary of the review methods, results and conclusions followed by a detailed critical assessment on the reliability of the review and the conclusions drawn.