Factors associated with dropout in a group weight-loss programme: a longitudinal investigation

Area of Science:

• Behavioral Science
• Obesity Research
• Public Health Interventions

Background:

• Attrition significantly limits the effectiveness of weight management interventions.
• Understanding factors associated with dropout is crucial for improving program adherence.

Purpose of the Study:

• To investigate personal, sociodemographic, and treatment-related factors linked to attrition at various stages of a 10-week group weight-loss program.
• To identify predictors of dropout throughout the intervention, including early, mid, and late stages.

Main Methods:

• A longitudinal clinical intervention study involving 587 participants (90% female, mean age 46 years, mean BMI 31.9 kg/m²).
• Comparison of three groups: Control, Behavioural Intentions, and Implementation Intentions over 10 weeks.
• Logistic regression models with multiple imputations were used to analyze weekly and overall dropout rates.

Main Results:

• A smaller reduction in body mass index (BMI) during the initial 2 weeks was the most significant predictor of dropout across most weeks.
• Dropout in the final week (week 10) showed a different pattern, with 56% of total dropout occurring then.
• The final week's dropout model, unlike earlier weeks, considered BMI reduction in the preceding 2 weeks but not at the intervention's start.

Conclusions:

• Initial weight loss is a critical, independent determinant of dropout in adult weight-loss programs, except for the final week.
• This finding offers a simple yet powerful method for assessing major dropout risk factors.
• Interventions should focus on promoting early weight loss to enhance participant retention.