Enhanced patient counselling and SMS reminder messages to improve access to community-based eye care services in Meru, Kenya: statistical analysis plan for a Bayesian adaptive trial

Background Health service programmes frequently encounter challenges with patient adherence to care. A promising, low-risk approach to address this issue is providing patients with targeted information about the importance of adherence. In the Vision Impact Project (VIP), an eye health screening programme in Kenya, the adherence rate to attending triage clinics after referral is around 50%. To improve this rate, this trial will test the effectiveness of delivering relevant information to patients at the point of referral along with reminder messages. Methods A pragmatic, Bayesian adaptive trial will be conducted within the VIP programme to assess the effectiveness of providing enhanced information compared to standard care. Weekly interim analyses will monitor adherence rates to referral appointments following positive vision impairment screenings. Participants will be randomized equally into intervention and control groups. The trial will stop if interim findings indicate either efficacy of one arm over the other, or futility that the two arms are performing equally. Discussion This paper presents the statistical analysis plan for a pragmatic adaptive trial aimed at improving adherence in an eye screening programme in Kenya. This statistical analysis plan expands on the design and analysis plan detailed in the study protocol and documents decision rules to avoid post hoc decision-making. Trial registration ISRCTN 11329596, Registered on 02 February 2024, https://doi.org/10.1186/ISRCTN11329596