Age differences in the impact of a Positive Deviance/Hearth programme on the nutritional status of children in rural Bangladesh

Objective: To examine the difference in the rehabilitation rate from underweight by child age at enrolment in the Positive Deviance (PD)/Hearth programme. Design: This secondary data analysis used programme monitoring records of underweight children aged 6-60 months attending a 2-week PD/Hearth session and followed up for 6 months in Sep. 2018-Mar. 2019. Data were analysed using multi-level mixed-effect regression and poisson regression with robust variance. Setting: Rajshahi Division, Bangladesh Participants: A total of 5,227 underweight (weight-for-age z-score [WAZ]<-2) children who attended the PD/Hearth sessions. Results: From enrolment to six months follow-up, the mean WAZ improved from -2.80 to -2.09, and the percentage of underweight children decreased to 54.5%. Compared to the enrolment age of 6-11 months, the estimated monthly change in WAZ at six months of follow-up were 0.05 lower for 12-23 months, 0.06 lower for 24-35 months, and 0.09 lower for 36-60 months of the enrolment age (all p<0.001). The probability of rehabilitation at six months of follow-up were lower by 16.7% for 12-23 months (RR=0.83; 95% CI: 0.77, 0.91), 15.5% for 24-35 months (RR=0.84; 95% CI: 0.78, 0.92), and 34.9% for 36-60 months of the enrolment age (RR=0.65; 95% CI: 0.59, 0.72), compared to the enrolment age of 6-11 months. Conclusions: Enrolment in the PD/Hearth programme at a younger age had the advantage of greater rehabilitation from underweight than older age. Our findings provide a better understanding of the successes and failures of the PD/Hearth programme to achieve more sustainable and cost-effective impacts.