Protocol for cost-effectiveness analysis of a randomised trial of mHealth coaching (Bump2Baby and Me) compared to usual care for healthy gestational weight gain and postnatal outcomes in at-risk women and their offspring

Background: Gestational diabetes mellitus (GDM) and overweight are associated with an increased likelihood of complications during birth and for the newborn baby. These complications lead to increased immediate and long-term healthcare costs as well as reduced health and wellbeing in women and infants. This protocol presents the health-economic evaluation to investigate the cost-effectiveness of Bump2Baby and Me (B2B&Me), which is a health coaching intervention delivered via smartphone to women at risk of gestational diabetes. Methods: Using data from the B2B&Me randomised controlled trial, this economic evaluation compares costs and health effects between the intervention and control group using the incremental cost-effectiveness ratio. Direct healthcare costs, costs of pharmaceuticals and intervention costs will be included in the analysis, body weight and quality-adjusted life years will serve as the effect outcomes. To investigate the long-term cost-effectiveness of the trial, a Markov model will be employed. Deterministic and probabilistic sensitivity analysis will be employed. Discussion: GDM is a growing public health concern affecting both short and long-term health outcomes and healthcare costs. Identifying cost-effective options for prevention is an international global priority. This protocol describes the methods for calculating the short-term and long-term cost-effectiveness of an intervention aimed at preventing GDM, overweight and obesity amongst women during pregnancy and the first year postpartum. Trial registration Australian New Zealand Clinical Trials Registry ACTRN12620001240932. Registered on 19 th November 2020