“CATCH-IT Reports” are Critically Appraised Topics in Communication, Health Informatics, and Technology, discussing recently published ehealth research. We hope these reports will draw attention to important work published in journals, provide a platform for discussion around results and methodological issues in eHealth research, and help to develop a framework for evidence-based eHealth. CATCH-IT Reports arise from “journal club” - like sessions founded in February 2003 by Gunther Eysenbach.
Monday, December 7, 2009
CATCH-IT Final Report: Web-based weight loss in primary care: A RCT
Abstract: click here
Slide presentation: click here
Draft report: click here
The purpose of this paper is to review the study by Bennett et al.(1) on their web-based behavior modification intervention for weight loss. With rising obesity rates around the world,(2) there is a need for weight loss interventions that are accessible to a larger number of individuals. Behavior therapy can significantly enhance comprehensive weight loss strategies,(3) but access to lifestyle interventions are limited by costs and availability of counseling services. The authors present a web-based tool with the potential for wide scale implementation at low costs.
The objective of the study was to evaluate the short-term (12-week) efficacy of a web-based intervention in primary care patients with obesity (BMI 30 to 40 kg/m2) and hypertension.
A total of 101 obese, hypertensive patients were randomized to receive either the web-based intervention (n=51) or usual care (n=50). Intervention participants had access to the comprehensive weight loss website for 3 months, and four counseling sessions (two in-person sessions and two telephone sessions). Counseling was provided by a health coach (registered dietician) trained to use principles of motivational interviewing. The health coach provided counseling on “obesogenic” behavior goals (determined at the start of the intervention). Participants could select new goals at week 6. The primary purpose of the website was to facilitate daily self-monitoring of adherence to behavior change goals.
Participants in the usual care group received the standard care offered by the outpatient clinic. They were also given a copy of the “Aim for a Healthy Weight” document published by the National Heart Lung and Blood Institute.(4)
At baseline, and at 3 month follow-up, participants completed a web-based survey followed by anthropometric measures and blood pressure assessments. Participants were offered $25 for attending each assessment.
Primary outcome: Greater weight loss was reported in the intervention group (-2.281 kg +/- 3.21) than the usual care group (0.28 +/- 1.87 kg); mean difference -2.56 kg (95% CI -3.60, -1.53). Intervention participants lost a greater percentage of baseline body weight (-2.6% +/- 3.3%) than usual care participants (0.39% +/- 2.16%); mean difference -3.04% (95% CI -4.26, -1.83). About a quarter of intervention participants (25.6%) lost >5% of their initial body weight at 12-week. None of the usual care participants lost > 5% body weight in the study period.
Secondary outcomes: A reduction in BMI was observed among the intervention group (-0.94 +/- 1.16 kg/m2) compared to an increase in BMI in the usual care group (0.13 +/- 0.75 kg/m2); mean difference -0.07 kg/m2 (95% CI -1.49, -0.64). No statistically significant differences were found for waist circumference, systolic blood pressure, and diastolic blood pressure.
Participants meeting the login goal (3 times per week) for at least 6 weeks had greater weight loss (-3.30 +/- 3.78 kg) than those who met the login goal for less than 6 weeks (-0.42 +/- 1.78 kg); mean difference: -2.88 kg (95% CI -1.56, -4.60). Those who met the login goal for 10 weeks (83% of study weeks) demonstrated much greater weight loss (-4.50 +/- 3.29 kg) than those who did not (-0.60 +/- 1.87); mean difference: -3.90 kg; (95% CI -2.43, -5.36).
No association was found between participation in four coaching sessions and weight loss.
Bennett et al. reported short term weight loss of -2.25kg +/- 3.21 using a web based behavioral intervention. While this result is statistically significant, the small amount of weight loss is of limited clinical significance. Obesity guidelines suggest losing 10% of initial body weight (e.g., 10% of 100kg person = 10kg) for clinical benefits.(5,6)
The weight loss reported in the study was somewhat lower than weight loss reported in other weight loss internet interventions.(7) The authors suggested that dietary restrictions would be necessary to achieve results of larger magnitude. However, the rationale for treating obese patients with behavior therapy alone is not clear. Canadian obesity guidelines recommend diet and physical activity as the first-line treat of obesity. Behavior interventions are considered as an adjunct to other interventions.(3)
The relatively short study period was also somewhat unusual since long-term weight loss is the main challenge in obesity. The trial period of 12 weeks is much shorter than study periods reported by other studies.(6)
According to the authors, the intervention was developed to overcome the challenge of long term adherence. Adherence to behavior change strategies often wanes over time. Unfortunately, adherence to the web based intervention also decreased over the study period with 78% who met login goal at week 1, versus 43.1% at 12 weeks.
The authors suggested that the web based intervention can be implemented without a health coach. But, success without coach support may be less since a research assistant (health coach) contacting participants can act as a “push” factor that lowers attrition rates.(8)
Some of the references noted in the paper do not support the text. For example, on page 2, the paper states that “research staff subsequently collected anthropometric measures and blood pressure using established procedures (reference 20).” However, reference 20 refers to a 24 page survey NHANES food questionnaire.(9)
Some of the numbers reported in the paper need revisiting. For example, Table 1 (page 2) indicates that intervention participants (n = 51) had a higher body weight (101.0 kg +/- 15.4) than usual care participants (n = 50) with a body weight of (97.3 kg +/- 10.9). But, the body weight of all participants (n=101) was also reported as (97.3 kg +/- 10.9).
Despite all the weaknesses noted above, the study was well designed. The paper included most items on the CONSORT(10,11) and STARE-HI(12) checklists. Although the authors did not explicitly state that this was a pilot study, it appears that they have already begun other trials using their iOTA approach (see website).
The web intervention included many interesting features such as the display of the “average performance for other program participants,” regular updates to behavioral skills needed to adhere to obesogenic behavior change goals, social networking forum, recipes.
The obesogenic behavior change goals are very short and simple ("Walk 10,000 steps every day," "Watch 2 h or less of TV every day," "Avoid sugar-sweetened beverages," "Avoid fast food," "Eat breakfast every day," and "No late night meals and snacks"). Christensen(13) suggests that “shorter interventions” could be the primary role of the internet in disease prevention instead of delivery of lengthy therapy that requires hours of online work.
In terms of future research, it would be interesting to compare the web based intervention with other weight loss interventions. Although comparison with “usual care” may be common practice in randomized controlled trials, a “head-to-head” trial with an alternative intervention may contribute more knowledge. For instance, a comparison of the web based intervention with a paper based monitoring tool could be very informative, since it would allow analysis of web enabled features.
1. In the usual care group, what was standard care? How many visits did the usual care group make to the primary care provider for weight reduction?
2. Of the 124 ineligible participants, what were the reasons for ineligibility?
3. What was the web based survey completed by participants at baseline and at 3 months follow-up? Was the NHANES food questionnaire used as the web based survey? What were the results of the survey?
4. Table 3 (page 4) excluded the one participant who did not login once. Given that the range of logins from week 1 to week 12 includes “0”, why was this data omitted?
5. Intervention participants received “two 20-min motivational coaching sessions in person (baseline and week 6), and two, 20-min biweekly sessions via telephone (week 3 and 9)”. Were there biweekly telephone coaching sessions in addition to the two telephone sessions at week 3 and week 9? What was the impact of the “message feature that allowed for direct communication with the coach”? Was there extended access to the health coach beyond the four sessions throughout the 12 week study period?
6. With regards to the web-based intervention, what was being tracked by the web-based intervention (number of times eat out, number of stairs walked)? How many minutes on average did each session take? What behaviour skills were presented on the website and updated biweekly? What was the impact of the social networking forum?
1. Bennett G Bennett GG, Herring SJ, Puleo E, Stein EK, Emmons KM and Gillman MW. Web-based Weight Loss in Primary Care: A Randomized Controlled Trial. Obesity (2009) Advance online publication, 20 August 2009. DOI:10.1038/oby.2009.242
2. OECD Health Data 2009: How Does Canada Compare. http://www.oecd.org/dataoecd/46/33/38979719.pdf
3. Lau DCW, Douketis JD, Morrison KM, Hramiak IM, Sharma AM, Canadian clinical practice guidelines on the management and prevention of obesity in adults and children. CMAJ 2007;176(8 suppl):Online-1–117 www.cmaj.ca/cgi/content/full/176/8/S1/DC1
4. National Heart, Lung, and Blood Institute, National Institutes of Health. Aim for a Healthy Weight. Washington DC: US Department of Health and Human Services, 2005. http://www.nhlbi.nih.gov/health/public/heart/obesity/aim_hwt.pdf
5. Wadden TA, Butryn ML, Wilson C. Lifestyle modification for the management of obesity. Gastroenterology. 2007 May;132(6):2226-38.
6. Sarwer DB, von Sydow Green A, Vetter ML, Wadden TA. Behavior therapy for obesity: where are we now? Curr Opin Endocrinol Diabetes Obes. 2009 Oct;16(5):347-52. DOI: 10.1097/MED.0b013e32832f5a79
7. M. Neve, P. J. Morgan, P. R. Jones and C. E. Collins. Effectiveness of web-based interventions in achieving weight loss and weight loss maintenance in overweight and obese adults: a systematic review with meta-analysis. Obesity Reviews. 2009 Sep 14 DOI: 10.1111/j.1467-789X.2009.00646.x
8. Eysenbach Gunther. The Law of Attrition. J Med Internet Res. 2005;7(1):e11. doi: 10.2196/jmir.7.1.e11. http://www.jmir.org/2005/1/e11/v7e11
9. National Heart, Lung, and Blood Institute, National Institutes of Health. Aim for a Healthy Weight. Washington DC: US Department of Health and Human Services, 2005. http://www.nhlbi.nih.gov/health/public/heart/obesity/aim_hwt.pdf
10. Moher D, Schulz KF, Altman DG for the CONSORT Group. The CONSORT Statement: Revised Recommendations for Improving the Quality of Reports of Parallel-Group Randomized Trials. Ann Intern Med. 2001;134:657-662. (http://www.consort-statement.org)
11. Altman DG, Schulz KF, Moher D, Egger M, Davidoff F, Elbourne D, Gøtzsche PC, Lang T for the CONSORT Group. The Revised CONSORT Statement for Reporting Randomized Trials: Explanation and Elaboration. Ann Intern Med. 2001;134:663-694. (http://www.consort-statement.org)
12. Talmon J, Ammenwerth E, Brender J, de Keizer N, Nykänen P, Rigby M. STARE-HI--Statement on reporting of evaluation studies in Health Informatics. Int J Med Inform. 2009 Jan;78(1):1-9.
13. Christensen H, Ma A. The Law of Attrition Revisited. (J Med Internet Res 2006;8(3):e20) doi:10.2196/jmir.8.3.e20. http://www.jmir.org/2006/3/e20/