Effect of a stepped-care intervention approach on weight loss in adults: a randomized clinical trial

Abstract

Context: Given the obesity epidemic, effective but resource-efficient weight loss treatments are needed. Stepped-treatment approaches customize interventions based on milestone completion and can be more effective while costing less to administer than conventional treatment approaches.

Objective: To determine whether a stepped-care weight loss intervention (STEP) compared with a standard behavioral weight loss intervention (SBWI) would result in greater weight loss.

Design, setting, and participants: A randomized clinical trial of 363 overweight and obese adults (body mass index: 25-<40; age: 18-55 years, 33% nonwhite, and 83% female) who were randomized to SBWI (n = 165) or STEP (n = 198) at 2 universities affiliated with academic medical centers in the United States (Step-Up Study). Participants were enrolled between May 2008 and February 2010 and data collection was completed by September 2011.

Interventions: All participants were placed on a low-calorie diet, prescribed increases in physical activity, and attended group counseling sessions ranging from weekly to monthly during an 18-month period. The SBWI group was assigned to a fixed program. Counseling frequency, type, and weight loss strategies could be modified every 3 months for the STEP group in response to observed weight loss as it related to weight loss goals.

Main outcome measure: Mean change in weight over 18 months. Additional outcomes included resting heart rate and blood pressure, waist circumference, body composition, fitness, physical activity, dietary intake, and cost of the program.

Results: Of the 363 participants randomized, 260 (71.6%) provided a measure of mean change in weight over 18 months. The 18-month intervention resulted in weight decreasing from 93.1 kg (95% CI, 91.0 to 95.2 kg) to 85.6 kg (95% CI, 83.4 to 87.7 kg) (P < .001) in the SBWI group and from 92.7 kg (95% CI, 90.8 to 94.6 kg) to 86.4 kg (95% CI, 84.5 to 88.4 kg) in the STEP group (P < .001). The percentage change in weight from baseline to 18 months was -8.1% (95% CI, -9.4% to -6.9%) in the SBWI group (P < .001) compared with -6.9% (95% CI, -8.0% to -5.8%) in the STEP group (P < .001). Although the between-group difference in 18-month weight loss was not statistically different (-1.3 kg [95% CI, -2.8 to 0.2 kg]; P = .09), there was a significant group × time interaction effect (P = .03). The cost per participant was $1357 (95% CI, $1272 to $1442) for the SBWI group vs $785 (95% CI, $739 to $830) for the STEP group (P < .001). Both groups had significant and comparable improvements in resting heart rate, blood pressure level, and fitness.

Conclusions: Among overweight and obese adults, the use of SBWI resulted in a greater mean weight loss than STEP over 18 months. Compared with SBWI, STEP resulted in clinically meaningful weight loss that cost less to implement.

Trial registration: clinicaltrials.gov Identifier: NCT00714168.

Figure 1

Consort Diagram

Figure 2

Transition across weight loss steps in Stepped-Care (STEP) Intervention (N=198)