Feasibility of a peer-supported, WhatsApp-assisted, lifestyle modification intervention for weight reduction among adults in an urban slum of Karachi, Pakistan: a mixed-methods, single-group, pretest-post-test, quasi-experimental study

Objectives: This pilot study assessed whether a peer-supported, WhatsApp-assisted lifestyle modification intervention for weight reduction is feasible to execute a definitive trial.

Design: A mixed-methods, single group, pretest and post-test, quasi-experimental study.

Setting: Azam Basti, an urban slum in Karachi, Pakistan.

Participants: Fifty participants (males and females aged 20-60) with a body mass index of >23 kg/m², along with their nominated peers from the same family.

Intervention: Using motivational interviewing techniques, a trained nutritionist delivered the lifestyle modification intervention to the participants and peers for 3 days after the baseline assessment and then once monthly for 1 year. The intervention was delivered in groups using WhatsApp voice calls. The education sessions mainly focused on dietary modifications, physical activity advice and peer-support assignments to achieve a 5% wt loss from the participant's initial body weight.

Outcomes: The feasibility measures included screening, recruitment, retention and monthly interview response rates. At 1 year, in-depth interviews (IDIs) with participants and peers were conducted to explore the facilitators, barriers, acceptability and experiences of the intervention. Changes in weight, calorie intake/day and calorie expenditure/day were also assessed.

Results: The recruitment and retention rates were 32% (n=50/156) and 78% (n=39/50), respectively, while the response rate for monthly interviews ranged between 66% (n=33) and 94% (n=47). The mean weight loss at 1 year was 2.2 kg, and the reduction in mean calorie intake was 386 kcal/day. There were no changes in the mean calorie expenditure. During the IDIs, participants and peers reported intervention via WhatsApp and peer support as convenient, flexible and supportive.

Conclusions: The quantitative and qualitative findings of the current pilot study support the scale-up of this work with minor modifications to the screening method as well as close monitoring and motivational interviewing to improve adherence in terms of physical activity.

Trial registration number: NCT05928338.