Cluster Randomised Control Trial to determine the effectiveness of safe storage to prevent self- poisoning: report of design, community participation and implementation challenges

Introduction  Pesticide poisoning is a major public health problem in rural Asia, especially in agricultural communities. The WHO recognises pesticide poisoning to be the single most important global means of suicide. There is convincing evidence that restricting access to commonly used, highly lethal methods of suicide not only reduces method-specific rates of suicide  but also significantly affects overall rates of suicide. Numerous pilot studies of safe storage of pesticides have shown its acceptability by the community.  However, before this approach can be more widely promoted across Asia, evidence is required to determine the effectiveness, cost and safety of this approach.  

Methods and Results:  We have started a community-based cluster randomised controlled trial (RCT) of the effectiveness of safe storage containers to reduce pesticide self-poisoning. We will recruit rural villages from five administrative divisions in the Anuradhapura District of Sri Lanka.  Community approval will be sought and a census carried out, collecting baseline data from all households on demographics, pesticide usage, previous self-reported self-harm and socio-economic status. Intervention households, determined by their use of pesticides, will be offered a free UV-resistant polyethylene in-ground container with a lock. The safe storage device was developed and piloted following input from industry and farmers.   The primary outcome will be the incidence of pesticide self-poisoning, both fatal and non-fatal. Secondary outcomes will include the incidences of pesticide poisoning, self-harm (all methods both fatal and non-fatal), self-poisoning (all substances) and unintentional poisoning in children. Power calculations suggest that 217,944 person years of follow-up are required in each arm of the trial to compensate for non-eligibility, non-compliance and contamination (24,216 households; 81 villages per arm; total 162 villages).  

Discussion:  The presentation will discuss the challenges of conducting such a study, including design issues with the safe storage device; community engagement; logistics; and promotion activities to ensure compliance.