12-month outcomes and process evaluation of the SHED-IT RCT: an internet-based weight loss program targeting men

Abstract

This article reports the 12-month follow-up results and process evaluation of the SHED-IT (Self-Help, Exercise, and Diet using Information Technology) trial, an Internet-based weight loss program exclusively for men. Sixty-five overweight/obese male staff and students at the University of Newcastle (Callaghan, Australia) (mean (s.d.) age = 35.9 (11.1) years; BMI = 30.6 (2.8)) were randomly assigned to either (i) Internet group (n = 34) or (ii) Information only control group (n = 31). Both received one face-to-face information session and a program booklet. Internet group participants were instructed to use the study website for 3 months. Participants were assessed at baseline, 3-, 6-, and 12-month follow-up for weight, waist circumference, BMI, blood pressure, and resting heart rate. Retention at 3- and 12-months was 85% and 71%, respectively. Intention-to-treat (ITT) analysis using linear mixed models revealed significant and sustained weight loss of -5.3 kg (95% confidence interval (CI): -7.5, -3.0) at 12 months for the Internet group and -3.1 kg (95% CI: -5.4, -0.7) for the control group with no group difference. A significant time effect was found for all outcomes (P < 0.001). Per-protocol analysis revealed a significant group-by-time interaction for weight, waist circumference, BMI, and systolic blood pressure. Internet group compliers (who self-monitored as instructed) maintained greater weight loss at 12 months (-8.8 kg; 95% CI -11.8, -5.9) than noncompliers (-1.9 kg; 95% CI -4.8, 1.0) and controls (-3.0 kg; 95% CI -5.2, -0.9). Qualitative analysis by questionnaire and interview highlighted the acceptability and satisfaction with SHED-IT. Low-dose approaches to weight loss are feasible, acceptable, and can achieve clinically important weight loss in men after 1-year follow-up.