Hand-washing promotion for preventing diarrhoea

Background: Diarrhoea accounts for 1.8 million deaths in children in low- and middle-income countries (LMICs). One of the identified strategies to prevent diarrhoea is hand washing. Objectives: To assess the effects of hand-washing promotion interventions on diarrhoeal episodes in children and adults. Search methods: We searched CENTRAL, MEDLINE, Embase, nine other databases, the World Health Organization (WHO) International Clinical Trial Registry Platform (ICTRP), and metaRegister of Controlled Trials (mRCT) on 8 January 2020, together with reference checking, citation searching and contact with study authors to identify additional studies. Selection criteria: Individually-randomized controlled trials (RCTs) and cluster-RCTs that compared the effects of hand-washing interventions on diarrhoea episodes in children and adults with no intervention. Data collection and analysis: Three review authors independently assessed trial eligibility, extracted data, and assessed risks of bias. We stratified the analyses for child day-care centres or schools, community, and hospital-based settings. Where appropriate, we pooled incidence rate ratios (IRRs) using the generic inverse variance method and a random-effects model with a 95% confidence interval (CI). We used the GRADE approach to assess the certainty of the evidence. Main results: We included 29 RCTs: 13 trials from child day-care centres or schools in mainly high-income countries (54,471 participants), 15 community-based trials in LMICs (29,347 participants), and one hospital-based trial among people with AIDS in a high-income country (148 participants). All the trials and follow-up assessments were of short-term duration. Hand-washing promotion (education activities, sometimes with provision of soap) at child day-care facilities or schools prevent around one-third of diarrhoea episodes in high-income countries (incidence rate ratio (IRR) 0.70, 95% CI 0.58 to 0.85; 9 trials, 4664 participants, high-certainty evidence) and may prevent a similar proportion in LMICs, but only two trials from urban Egypt and Kenya have evaluated this (IRR 0.66, 95% CI 0.43 to 0.99; 2 trials, 45,380 participants; low-certainty evidence). Only four trials reported measures of behaviour change, and the methods of data collection were susceptible to bias. In one trial from the USA hand-washing behaviour was reported to improve; and in the trial from Kenya that provided free soap, hand washing did not increase, but soap use did (data not pooled; 3 trials, 1845 participants; low-certainty evidence). Hand-washing promotion among communities in LMICs probably prevents around one-quarter of diarrhoea episodes (IRR 0.71, 95% CI 0.62 to 0.81; 9 trials, 15,950 participants; moderate-certainty evidence). However, six of these nine trials were from Asian settings, with only one trial from South America and two trials from sub-Saharan Africa. In seven trials, soap was provided free alongside hand-washing education, and the overall average effect size was larger than in the two trials which did not provide soap (soap provided: RR 0.66, 95% CI 0.58 to 0.75; 7 trials, 12,646 participants; education only: RR 0.84, 95% CI 0.67 to 1.05; 2 trials, 3304 participants). There was increased hand washing at major prompts (before eating or cooking, after visiting the toilet, or cleaning the baby's bottom) and increased compliance with hand-hygiene procedure (behavioural outcome) in the intervention groups compared with the control in community trials (data not pooled: 4 trials, 3591 participants; high-certainty evidence). Hand-washing promotion for the one trial conducted in a hospital among a high-risk population showed significant reduction in mean episodes of diarrhoea (1.68 fewer) in the intervention group (mean difference −1.68, 95% CI −1.93 to −1.43; 1 trial, 148 participants; moderate-certainty evidence). Hand-washing frequency increased to seven times a day in the intervention group versus three times a day in the control arm in this hospital trial (1 trial, 148 participants; moderate-certainty evidence). We found no trials evaluating the effects of hand-washing promotions on diarrhoea-related deaths or cost effectiveness. Authors' conclusions: Hand-washing promotion probably reduces diarrhoea episodes in both child day-care centres in high-income countries and among communities living in LMICs by about 30%. The included trials do not provide evidence about the long-term impact of the interventions.