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Background: Approximately 50% of the deaths of children under the age of 5 can be attributed to undernutrition, which also encompasses severe acute malnutrition (SAM). Diarrhoea is strongly associated with these deaths and is commonly diagnosed solely based on stool frequency and consistency obtained through maternal recall. This trial aims to determine whether this approach is equivalent to a ‘directly observed method’ in which a health care worker directly observed stool frequency using diapers in hospitalised children with complicated SAM. Methods: This study was conducted at ‘Moyo’ Nutritional Rehabilitation Unit, Queen Elizabeth Central Hospital, Malawi. Participants were children aged 5-59 months admitted with SAM. We compared 2 days of stool frequency data obtained with next-day maternal-recall versus a ‘gold standard’ in which a health care worker observed stool frequency every 2 h using diapers. After study completion, guardians were asked their preferred method and their level of education. Results: We found poor agreement between maternal recall and the ‘gold standard’ of directly observed diapers. The sensitivity to detect diarrhoea based on maternal recall was poor, with only 75 and 56% of diarrhoea cases identified on days 1 and 2, respectively. However, the specificity was higher with more than 80% of children correctly classified as not having diarrhoea. On day 1, the mean stool frequency difference between the two methods was -0.17 (SD; 1.68) with limits of agreement (of stool frequency) of -3.55 and 3.20 and, similarly on day 2, the mean difference was -0.2 (SD; 1.59) with limits of agreement of -3.38 and 2.98. These limits extend beyond the pre-specified ‘acceptable’ limits of agreement (±1.5 stool per day) and indicate that the 2 methods are non-equivalent. The higher the stool frequency, the more discrepant the two methods were. Most primary care givers strongly preferred using diapers. Conclusions: This study shows lack of agreement between the assessment of stool frequency in SAM patients using maternal recall and direct observation of diapers. When designing studies, one should consider using diapers to determining diarrhoea incidence/prevalence in SAM patients especially when accuracy is essential. Trial registration number:ISRCTN11571116(registered 29/11/2013).
This study was conducted at ‘Moyo’ NRU at Queen Elizabeth Central Hospital (QECH), the academic teaching hospital at the College of Medicine (COM), University of Malawi. As well as being a referral centre for the whole Southern Region of Malawi, ‘Moyo’ provides inpatient SAM treatment services for the whole of Blantyre urban and rural district, covering a population of approximately 1 million. Participants were children aged 5–59 months admitted with SAM defined as: weight-for-height ≤ −3 Z-scores (WHO growth standards) and/or a mid-upper-arm circumference (MUAC) of <115 mm (non-oedematous malnutrition, “marasmus”), and/or nutritionally induced bilateral pitting oedema (oedematous malnutrition, “kwashiorkor” and “marasmic kwashiorkor”). Oedema was defined as: Oedema level-I (+) is bilateral pitting oedema affecting the ankles/ft; level-II (++) affects both feet, hands, lower arms and lower legs; and level-III (+++) is generalized bilateral pitting oedema including both feet, legs, arms and face. All patients had complicated SAM; with medical complications like systemic or respiratory infection, gastroenteritis or HIV disease. Those with uncomplicated SAM would have been treated as outpatients in community-based treatment programs in Blantyre district [10]. After taking informed consent, we prospectively enrolled children with SAM into our study lasting the first 3 days of admission. For the StoolSAM study we assessed stool frequency and consistency prospectively in 120 SAM patients (see below). We compared the current MOYO practice of maternal-reported stool frequency (with a picture aid to help accurate recall during the previous night/day, see Fig. Fig.1)1) versus a ‘gold standard’ in which a health care worker observed stool frequency using diapers. Simple picture aid used to help primary care giver recall stool frequency of child with SAM As ‘gold standard’ (the direct observation method) diapers were assessed for presence and consistency of stools every 2 h during office hours (8 AM-6 PM), 7 days a week, by one of two members of the study team (AB, IP), thereafter we noted the number of diaper-changes made by the caregiver. For the maternal recall, we used the standard departmental questionnaire administered during the clinicians’ morning ward round, roughly between 9 and 11 am each day. Supporting the questionnaire, primary care givers were shown a picture aid to help accurate recall of stool frequency during the previous 24 h night and day period (see Fig. Fig.1).1). For simplicity, we here use the common term ‘maternal recall’ as primary care givers were by and large the actual mother of the child. Study patients were assessed both on week as well as weekend days. We did not have the resources to directly and regularly observe diaper-based output throughout the night (6 PM-8 AM). However, primary care givers were allowed to change diapers as needed, enabling the study team to count the diapers used the following morning and tally the total diapers used in each 24 h period. Diapers were observed by the study team to confirm watery stool rather than urine. After completing the 3-day study, guardians were asked which of the two methods they preferred and what level of education they had obtained. To assess maternal preference, we used a 1–5 scale: 1: strongly prefers diapers, 2: prefers diapers a little, 3: doesn’t mind which method was used, 4: prefers recall method a little, 5: strongly prefers recall method. Guardians were then prompted to explain their choice (free text) on the above-mentioned 5-point scale. We initially designed, registered and conducted the study as an RCT (see Additional file 1 for study flow chart). First, we aimed to establish whether stool frequency reported by care givers differed if diapers were also being directly assessed by staff health workers; insuring that “maternal reporting” is representative of normal practice even though direct observation is also being conducted. This also allowed us to check if diarrhoea prevalence estimated with maternal recall was the same in group-1 (“recall only” – unbiased by seeing diapers) and group-2 (“recall and diaper observation”). Recognising the limitations of this design (i.e. the assumption that true numbers of diarrhea stools are the same in the two groups) we also performed a post-hoc secondary analysis focusing on the discrepancies in stool frequency obtained by the two methods in each individual child of group-2. The randomization sequence was computer generated. Allocation concealment was achieved by inserting group labels into sealed, sequentially numbered opaque envelopes. At enrolment, the guardian drew the next numbered envelope and opened it in presence of a study team member to show their assigned group. Difference in stool frequency by maternal recall between group-1 and group-2 were assessed using generalized linear models with a Poisson distribution error for count data. Difference between the 2 groups in diarrhoea prevalence as obtained by maternal recall was assessed with Fisher Exact test. We took our ‘gold standard’ measurement of diarrhoea as having three or more diapers with ‘loose’ or worse consistency during the 14-h daytime observation period. The sensitivity and specificity of using stool frequency assessed by maternal recall to classify children as having diarrhoea or not were estimated with 95% confidence intervals for both day 1 and day 2. We analyzed all patients with sufficient data to be classified. Since maternal recall is always retrospective in nature and diapers prospective, day 2 recall was compared with day 1 diaper data, and similarly, day 3 recall was compared with day 2 diaper data. We recruited 58 children for group-2 (with both recall and diaper observation): this sample size assumed that a clinically relevant limit of agreement would be ±1.5 stool episodes per day (alpha = 0.025; beta, power = 80%; SD 2.5). These figures were based on a review of recent case notes of patients admitted to our ward. To establish agreement, mean differences and limits of agreement between methods were calculated with the R package MethComp [11] which is based on the Bland-Altman approach [12]. Generalized linear models with Poisson error distribution were used to relate stool frequency and primary care giver education with absolute discrepancy between methods. For analysis, WHZ, WAZ, HAZ and MUAC Z-scores were calculated using the WHO Child Growth Standards R package: igrowup [13]. Data entry was done with Microsoft access. Stata version 12.0 (StataCorp USA), SPSS and R (Version 3.2.3) were used for further analyses. Significance threshold was set at 5% for all statistical tests. The Malawi College of Medicine Research and Ethics Committee approved this study (P.07/13/1429) and all research associated activities were carried out according to Good Clinical Practice guidelines which are based on the Declaration of Helsinki [14].
