Effects of complexity of handwashing instructions on handwashing procedure replication in low-income urban slums in Bangladesh: a randomized non-inferiority field trial


 Handwashing instructions vary in complexity, with some recommending multiple steps. To assess whether complex handwashing instructions changed handwashing procedure replication, we conducted a randomized non-inferiority trial in a low-income area, Dhaka. We randomly assigned mothers and children aged 5–10 years to one of three handwashing instruction sets: simple (N = 85 mothers/134 children), moderate (N = 75 mothers/148 children), or complex (84 mothers/147 children). Simple instructions had three steps: wet, lather, and rinse hands, and moderate included the simple instructions plus steps to scrub palms, backs of hands, and dry hands in the air. Complex instructions included moderate instructions plus steps to scrub between fingers, under nails, and lather for 20 s. After baseline, cue cards were used to promote handwashing instructions, and adherence after 2 weeks of interventions was evaluated. Compliance with handwashing procedure replication to all instructions in simple, moderate, and complex increased after the intervention among mothers and children. Compliance to all instructions in the simple group was higher in the simple group (100%) compared to all instructions in moderate (47%) and complex instruction groups (38%). Simple handwashing steps are easier to remember for long time periods compared to complex steps.


INTRODUCTION
In 2013, the World Health Organization estimated a total of 297,000 deaths attributed to inadequate handwashing, mostly from low-income countries (WHO ). Handwashing with soap has been considered one of the most effective ways of reducing infectious diseases (Fewtrell et  For example, studies of patients using antiretroviral therapy for HIV/AIDS have shown that increased complexity in the medication regimen resulted in decreased patient adherence (Stone et al. ). A 17 country review on adherence to medication suggested that adherence to intake medication increased up to 10% when patients switched from the combination of multiple drugs to simpler single-dose therapy (Hutchins et al. ).
Several studies have investigated the effects of different regimens of handwashing complexity on microbial hand contamination. A recent community-based microbial handwashing effectiveness observational study in Zimbabwe found that a regimen of wetting hands by dipping into a vessel, using any soap, scrubbing the fingertips, and cleaning under the fingernails significantly lowers the contamination in post-wash hand rinse samples compared to pre-wash (Friedrich et al. ). The rest of the steps (scrubbing back of the hands, scrubbing between fingers, and scrubbing for >20 s) did not significantly remove Escherichia coli. ), but no study has been conducted to assess the impact of handwashing instruction complexity for handwashing procedure replication on the behavior at the community level. In a low-income urban area in Dhaka, Bangladesh, we conducted a randomized non-inferiority field trial among mothers of young children and children aged 5-10 years to evaluate whether increasingly complex handwashing instructions reduced handwashing procedure replication. We also assessed whether the complexity of handwashing instructions affected the ability of respondents to recall recommended times to wash hands.

METHODS
A non-inferiority trial aims to demonstrate that the test product is not worse than the comparator by more than a small pre-specified amount (Ricci ). For this study, we defined a non-inferiority trial to determine whether moderate and/or complex handwashing instructions (a new treatment) result in compliance with handwashing procedure replication that is not worse than simple handwashing instructions (the reference treatment) by more than an acceptable amount (Piaggio et al. ). This amount is known as the non-inferiority margin or delta. There was no prior information on the specific topic of the complexity of handwashing instruction and handwashing behavior, and we assumed that moderate and/or complex handwashing instructions were 25% less adheres compared to simple handwashing instructions. For this study, we defined handwashing procedure replication as the demonstration of the full set of prescribed instructions provided to the respondents after baseline data collection.

Study site
We conducted this study from July to October 2010 in the Jafrabad area of Dhaka, a densely populated low-income area where people live in compounds containing multiple households (BBS ), and where the incidence of cholera is high (incidence rate of 1.64 per 1,000) (Chowdhury et al.

Enrolment of the study population
Fieldworkers surveyed all compounds in the Jafrabad area and prepared a line-list of 346 compounds. They then enrolled all compounds having more than four households (N ¼ 309 compounds) to maximize the likelihood that at least one eligible respondent would be identified in each compound. Using a Microsoft Excel random number generator, one of the investigators (DS) assigned 103 compounds each (from the 309 selected compounds) to one of three handwashing complexity instruction sequences: simple (three steps: wet hands with water, apply soap and produce lather, and rinse both hands), moderate (six steps: wet hands with water, apply soap and produce lather, scrub palms of hands, scrub back of hands, rinsed both hands, and dry hands by waving in the air), or complex (nine steps: wet hands with water, apply soap and produce lather, scrub palms of hands, scrub back of hands, scrub between fingers, clean under fingernails, scrub for at least 20 s rinse both hands, and dry hands by waving in the air) ( Figure 1).
Caregivers were considered eligible if they had a child <2 years old or a child 5-10 years old ( Figure S1, available with the online version of this paper). Mothers of children <2 years old were selected because they are the group to which handwashing is most often promoted. We chose to interview mothers of older children because the primary school age (5-10 years old) is considered an optimal time to promote new behaviors and since children at this age are expected to take responsibility for their own handwashing. (Dutton et al. ; WSP ) (all data relevant to children 5-10 years old are shown in the online Supplementary Appendix). Fieldworkers performed systematic random sampling to identify every fourth household of the compound to determine mothers and children meeting the eligibility criteria. In brief, one fieldworker entered the assigned compound and began at the first household on the left of the main compound entrance. At the fourth household counting in a clockwise direction, the fieldworker attempted to recruit a study participant. If no eligible mother was available, the fieldworker continued in a clockwise direction one household at a time until an eligible mother was recruited. After recruiting one mother in that compound, the data collector proceeded to the next compound to recruit another mother in the same manner.

Data collection and intervention delivery
The fieldworkers used a survey questionnaire to collect baseline data on household demographics, current water and sanitation-related knowledge and reported practices, asked them to perform a demonstration of usual handwashing behavior after defecation including hand drying, then recorded knowledge of recommended times to wash hands.
Once baseline data were collected, the fieldworker used a pictorial cue card for all groups to promote recommended times to wash hands (before preparing food, before eating, after defecation, and after cleaning a child's anus) ( Figure S2 We wanted to evaluate whether the increased number of steps in the complex group would alter recall of the information on when to wash hands. Thus, the respondent was asked to recall the recommended times at which hands should be washed with soap and demonstrate/show how to wash hands. We evaluated whether the complexity of the recommended handwashing steps affected immediate handwashing procedure replication and recall of key times for handwashing immediately following the intervention, compared to baseline.
Similar information was collected after 2 days and 2 weeks of intervention using the same methods in order to assess whether the time since intervention might affect the ability to reproduce the recommended handwashing steps and recall of key times to wash hands.

DATA ANALYSIS
To compare demonstrated handwashing practices of mothers between measurement at baseline and endline, we used the paired t-test. Since we measured the practices of one mother from each compound, we did not account for clustering. We also used the paired t-test to compare compliance to recommended handwashing times of mothers between measurement at baseline and endline. For children, we compared demonstrated handwashing practices between baseline and endline using a generalized linear model adjusting for pair matching. Since we measured the practices of more than one child from the same compound, we adjusted standard errors to account for clustering at the compound level.

ETHICS
Written informed consent was obtained from parents and assent was obtained from the children.   Figure S1). Mean ages of mothers and children were comparable across the groups (about 25 years for mothers and 7.5 years for children). The mean number of persons per household was 4.5 across groups. All intervention households (100%) had access to latrine facilities and among them, only 2-6% of households had access to a private latrine in their premises across the groups. Overall, more than 99% of households had access to municipal piped supplied water, and among them, only 7-15% sources were household private taps across the groups. Most of the household (95%) had access to water at the handwashing station but only 25-33% had soap across the groups. On average, only 13-17% of households had soap inside their latrine across the group, and the mean distances between handwashing station and latrines were between four and five paces. Almost all (99%) of the households had access to drinking water within the compound, and most of them were connected through piped water into a shared facility (Table 1).

Handwashing procedure replication by mothers
At baseline before the intervention, compliance to simple instructions was similar (wet hands with water ¼ 100%, apply soap and produce lather 63-66%, and rinse hands thoroughly ¼ 100%) across the intervention groups. Compliance to moderate and complex instructions was consistent across the intervention groups at baseline except for the step denoting air drying of hands ('dried hands in the air'; the simple group 11%, the moderate group 15%, and in the complex group only 5%) ( Table 2).
When we evaluated handwashing procedure replication to the moderate and complex instruction sets without inclusion of the air drying step, 88-98% of mothers in the