Research Article: Text messaging and brief phone calls for weight loss in overweight and obese English- and Spanish-speaking adults: A 1-year, parallel-group, randomized controlled trial

Date Published: September 25, 2019

Publisher: Public Library of Science

Author(s): Job G. Godino, Natalie M. Golaszewski, Greg J. Norman, Cheryl L. Rock, William G. Griswold, Elva Arredondo, Simon Marshall, Julie Kolodziejczyk, Lindsay Dillon, Fred Raab, Sonia Jain, Maggie Crawford, Gina Merchant, Kevin Patrick, Sanjay Basu

Abstract: BackgroundWeight loss interventions based solely on text messaging (short message service [SMS]) have been shown to be modestly effective for short periods of time and in some populations, but limited evidence is available for positive longer-term outcomes and for efficacy in Hispanic populations. Also, little is known about the comparative efficacy of weight loss interventions that use SMS coupled with brief, technology-mediated contact with health coaches, an important issue when considering the scalability and cost of interventions. We examined the efficacy of a 1-year intervention designed to reduce weight among overweight and obese English- and Spanish-speaking adults via SMS alone (ConTxt) or in combination with brief, monthly health-coaching calls. ConTxt offered 2–4 SMS/day that were personalized, tailored, and interactive. Content was theory- and evidence-based and focused on reducing energy intake and increasing energy expenditure. Monthly health-coaching calls (5–10 minutes’ duration) focused on goal-setting, identifying barriers to achieving goals, and self-monitoring.Methods and findingsEnglish- and Spanish-speaking adults were recruited from October 2011 to March 2013. A total of 298 overweight (body mass index [BMI] 27.0 to 39.9 kg/m2) adults (aged 21–60 years; 77% female; 41% Hispanic; 21% primarily Spanish speaking; 44% college graduates or higher; 22% unemployed) were randomly assigned (1:1) to receive either ConTxt only (n = 101), ConTxt plus health-coaching calls (n = 96), or standard print materials on weight reduction (control group, n = 101). We used computer-based permuted-block randomization with block sizes of three or six, stratified by sex and Spanish-speaking status. Participants, study staff, and investigators were masked until the intervention was assigned. The primary outcome was objectively measured percent of weight loss from baseline at 12 months. Differences between groups were evaluated using linear mixed-effects regression within an intention-to-treat framework. A total of 261 (87.2%) and 253 (84.9%) participants completed 6- and 12-month visits, respectively. Loss to follow-up did not differ by study group. Mean (95% confidence intervals [CIs]) percent weight loss at 12 months was −0.61 (−1.99 to 0.77) in the control group, −1.68 (−3.08 to −0.27) in ConTxt only, and −3.63 (−5.05 to −2.81) in ConTxt plus health-coaching calls. At 12 months, mean (95% CI) percent weight loss, adjusted for baseline BMI, was significantly different between ConTxt plus health-coaching calls and the control group (−3.0 [−4.99 to −1.04], p = 0.003) but not between the ConTxt-only and the control group (−1.07 [−3.05 to 0.92], p = 0.291). Differences between ConTxt plus health-coaching calls and ConTxt only were not significant (−1.95 [−3.96 to 0.06], p = 0.057). These findings were consistent across other weight-related secondary outcomes, including changes in absolute weight, BMI, and percent body fat at 12 months. Exploratory subgroup analyses suggested that Spanish speakers responded more favorably to ConTxt plus health-coaching calls than English speakers (Spanish contrast: −7.90 [−11.94 to −3.86], p < 0.001; English contrast: −1.82 [−4.03 to 0.39], p = 0.107). Limitations include the unblinded delivery of the intervention and recruitment of a predominantly female sample from a single site.ConclusionsA 1-year intervention that delivered theory- and evidence-based weight loss content via daily personalized, tailored, and interactive SMS was most effective when combined with brief, monthly phone calls.Trial NCT01171586

Partial Text: Overweight and obese adults have increased risk for several chronic diseases, including type 2 diabetes, hypertension, cardiovascular disease, and many types of cancer [1]. In 2014, costs associated with the growing obesity epidemic in the United States totaled $149.4 billion [2]. Hispanics are at increased risk for overweight and obesity compared to non-Hispanics and suffer disproportionately from obesity-related comorbidities [3,4]. Fortunately, research has shown that among those who are overweight and obese, a weight loss of 5% of body weight substantially decreases chronic disease risk [1]. However, most effective weight loss interventions are costly, require in-person behavioral counseling, and lack evidence of long-term effectiveness [5,6]. Furthermore, few have been evaluated in Hispanic populations, which account for 42.5% of the obese population and comprise the largest ethnic minority group in the USA [3,4,7].

The flow of participants through the study is shown in Fig 2. Of the 799 interested in the study, 298 were eligible and randomized to the following groups: ConTxt only (n = 101), ConTxt plus health-coaching calls (n = 96), and standard print materials (control group, n = 101). A total of 261 participants completed the M6 visit (87.2% completion rate), and 253 completed the M12 visit (84.9% completion rate). Seventeen participants withdrew or were removed from the study (e.g., became pregnant, no longer wanted to participate, did not comply with study protocols). Twenty-eight participants were lost to follow-up (e.g., unable to reach after numerous contact attempts via email, mail, phone, and text). Participants were 77% female, 41% Hispanic, 72% white, 21% primarily Spanish speaking, 44% college graduates or higher, 47% married, 18% in school, and 22% unemployed. Participants had a mean (SD) age of 41.7 (11.1) years and BMI of 32.7 (3.4) (Table 3).

An automated system that offered 2–4 personalized, tailored, and interactive SMS per day containing content that was theory- and evidence-based and focused on reducing energy intake and increasing energy expenditure was only efficacious when combined with brief monthly phone calls with a health coach. On average, the combined intervention resulted in a weight loss equal to 3.6%, contrasted against those in the control who lost 0.6%, at 1 year among a diverse sample of English- and Spanish-speaking adults who were overweight or obese. The intervention effects were consistent across other weight-related outcomes, such as BMI and body fat percentage measured via DXA, and this finding is consistent with a similar study [13] and contributes further evidence that SMS coupled with brief monthly health coach calls can support sustained weight loss. In contrast, SMS alone does not appear to have a significantly greater effect on weight loss than printed materials. This is aligned with previous research that indicates that SMS content may need to be supported with other methods in order to maximize its efficacy for changing weight-related behaviors [26,27].



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