Comparison of Methods for Delivering a Lifestyle Modification Program for Obese Patients

Context People who are obese have difficulty changing their lifestyle to lose weight. Contribution This trial compared 5 ways of providing support for lifestyle modification. It found that high-frequency telephone contact with a dietitian led to the same weight loss as in-person contact and more weight loss than with low-frequency or e-mail contact or no contact at all. Caution Many patients withdrew, and most were women. Implication Telephone contacts with dietitians are as effective as in-person appointments for helping patients lose weight, and both are more effective than education or occasional dietitian contact. The Editors Despite substantial increases in awareness of the disease burden associated with excess weight, the prevalence of obesity continues to increase (1, 2). Lifestyle modification, which includes a low-calorie diet, increased physical activity, and behavioral treatment, continues to be the cornerstone of weight management (3). However, the inability of most patients to sustain long-term lifestyle changes makes pharmacotherapy an attractive option. In one trial, the addition of sibutramine, 15 mg/d, to a lifestyle modification program resulted in weight loss at 12 months that was nearly twice that of each treatment alone (4). Academic medical centers typically produce the best weight-loss results by combining intensive behavioral modification programs with pharmacotherapy in a structured setting that requires patients to attend weekly individual or group behavioral treatment sessions led by dietitians or behavioral psychologists. Despite the additional benefits of combining interventions, primary care practitioners, the principal providers of obesity treatment (5), frequently prescribe medications but offer minimal lifestyle counseling. Possible reasons for omitting lifestyle counseling may be little or no training in behavioral counseling; inability to dedicate time for ongoing counseling; lack of multidisciplinary staff; inadequate infrastructure; and costs associated with more frequent visits, which are seldom covered by medical insurance. As a result, investigators have begun to explore alternative methods of providing lifestyle modification, such as telephone contact or Internet- and e-maildelivered interventions, which could decrease the demands of onsite behavioral programs, improve patient adherence, and reduce costs (69). However, to our knowledge, no study has directly compared these different methods of delivering and reinforcing the behavioral modification program. Thus, we aimed to examine the effect of 5 methods of delivering a lifestyle modification program in combination with the weight-loss medication sibutramine. We hypothesized that high-frequency face-to-face meetings with a dietitian would produce the greatest weight loss, whereas self-help would be associated with the least. Weight loss with telephone and e-mail interventions were expected to fall between these 2 groups. Methods Study Design This was a 6-month, open-label study. We assigned participants to 1 of 5 intervention groups by using a computer-generated randomization schedule consisting of randomly permuted blocks. Block length was 5. All groups received the same drug treatment, sibutramine, 10 mg/d, and a standardized lifestyle modification program for weight loss that included a printed manual and access to a weight-loss Web site. The method of delivering the lifestyle modification program varied among the intervention groups in frequency and type of contact with a dietitian. High frequency was weekly contact during the first 3 months and every other week during the following 3 months, and low frequency was monthly contact. The type of contact with the dietitian was either face-to-face or by telephone or e-mail. One group had no contact with a dietitianonly self-help with the lifestyle manual and access to the weight-loss Web site. We randomly assigned patients to high-frequency face-to-face counseling (HF-F2F), low-frequency face-to-face counseling (LF-F2F), high-frequency telephone counseling (HF-TEL), high-frequency e-mail counseling (HF-EMAIL), and self-help (SELF) (Figure 1). Figure 1. Study flow diagram. AE= adverse event; HF-EMAIL= high-frequency e-mail counseling; HF-F2F= high-frequency face-to-face counseling; HF-TEL= high-frequency telephone counseling; LF-F2F= low-frequency face-to-face counseling; SELF= self-help. * High frequency was weekly contact during weeks 1 to 12 and every other week during weeks 13 to 24. Low frequency was monthly contact. Participants defaulted at their request or were lost to follow-up. Study Sample Participants were to be men and women age 25 to 60 years who had a body mass index of at least 30 kg/m2 but less than 40 kg/m2. Participants had their own physicians for routine medical care and received screening for trial eligibility after responding to advertisements placed in the community. They had to be eligible to receive sibutramine (per the U.S. package insert), adhere to study-related procedures, and have access to the Internet and e-mail. We excluded participants if they had uncontrolled blood pressure (140/90 mm Hg); type 1 or 2 diabetes; coronary heart disease; chronic congestive heart failure; stroke; substantial metabolic, hepatic, or renal disease; current cancer; or gastric bypass surgery. We also excluded persons who in the past 6 months had lost 10% or more of their initial weight, participated in a structured weight-loss program, or taken weight-loss drugs. We excluded women who were pregnant or breastfeeding, and women of childbearing potential had to use adequate contraception. The first participant visit took place in August 2004, and the last participant was seen in April 2005. The study was conducted at 12 U.S. research centers comprising mostly nonacademic, independent clinics that had experience running clinical trials with obese patients. Local ethics committees approved the trial. Outcomes and Measurements The study's primary outcome was 6-month change in body weight. Secondary outcomes were 6-month changes in waist circumference; lipid, glucose, and insulin levels; blood pressure; weight-related symptoms; and quality of life. We obtained measurements of body weight, blood pressure, and pulse rate at baseline and at the end of weeks 2, 4, 12, and 24. We took waist circumference and biochemical measurements (fasting lipid, glucose, and insulin levels) at baseline and at the end of weeks 12 and 24. We did safety laboratory measurements (serum chemistry, hematology, and urinalysis) at screening and at the end of the study. We assessed patient-reported quality of life and symptom distress at baseline and at 24 weeks by using validated measures: the Impact of Weight on Quality of Life-Lite (IWQOL-Lite) (10) and the Weight-Related Symptoms Measure (WRSM) (11). We used percentage of contact participationcalculated as actual divided by expected contactas a measure of adherence to the intervention for the groups with dietitian contacts. We scheduled high-frequency groups for 18 contacts and low-frequency groups for 7 contacts. Lifestyle Modification Program We adapted the behavioral strategies and the support materials from the Diabetes Prevention Program (www.bsc.gwu.edu/dpp/manuals.htmlvdoc). Study dietitians had standardized lifestyle and Web site training before participating in the trial and received ongoing support through monthly teleconferences led by a senior dietitian and regular teleconferences with the Web site developer. Caloric Intake We instructed all participants to adopt a 750 kcal/ddeficit diet with a minimum intake of 1000 kcal/d for women and 1200 kcal/d for men. We estimated daily caloric requirements at baseline by using the HarrisBenedict formula and adjusted downward if patients lost 9.1 kg during treatment. The macronutrient composition of the diet consisted of 15% protein, 30% (or less) fat, and 55% carbohydrate. Physical Activity Recommendations We recommended walking as the primary method of physical activity. We gave all participants a pedometer and recommended increasing their number of steps per day by approximately 500 steps each week. We encouraged participants to build to a goal of 10000 steps per day. Behavioral Recommendations Behavioral treatment strategies included goal setting, self-monitoring (including weekly weighing and completion of daily food intake and physical activity logs), stimulus control, enlisting the support of family and friends, use of problem-solving skills to overcome barriers, cognitive restructuring, and coping with slips and lapses. Support Materials All participants received the same support materials, which were a lifestyle modification manual (both in print and electronic format) and access to an interactive weight-loss Web site application. We encouraged participants to log on to the Web site at least once a week. Statistical Analysis We selected the sample size to provide the study with 80% power to detect a 1.5% difference in weight loss between any 2 of the 5 groups on the basis of a 2-sample t test at the 5% level (2-sided) assuming a common SD of 2.6%. The primary statistical analysis used a mixed-model repeated-measures approach for longitudinal data. The mixed-model analysis included intervention, visit, and the intervention-by-visit interaction as fixed factors and baseline body weight as a covariate. We found clinical center to be an insignificant factor and removed it from the final model. This was a modified intention-to-treat analysis because it included all randomly assigned participants who had a baseline measurement and at least 1 postbaseline measurement of body weight, and participants were considered members of the intervention group in which they were randomly assigned, regardless of adherence. We did not follow participants who withdrew prematurely, but we used their partial data in the analysis. All 10 pairwise comparisons among the 5 intervention groups were to be done