Study design
This study used data from the Multiple Indicator Cluster Surveys (MICS) carried out in the DRC in 2018. The surveys were conducted by the National Statistical Office (NSO) and United Nations International Children’s Emergency Fund (UNICEF), in collaboration with relevant DRC Ministries. During data collection, following UNICEF guidelines, written informed consent was obtained from all participants (mothers) following an explanation of study objectives, assurance of the confidentiality of their identity, and a guarantee that there was no disadvantage to not participating in the study. All data were recruited anonymously via study identification numbers. A two-stage sampling method was used. At the first stage, three strata within each province, except Kinshasa, were created. Within each stratum, primary sample units (PSU) were selected with probability proportional to population size. In the second stage, 30 households were drawn from each of the 721 clusters, with 21,630 households selected in total. Details of these MICS have been previously described elsewhere [36]. For this study, MICS data were accessed and analyzed with the authorization of UNICEF.
The MICS were designed to collect updated information on the situation of women and children nationally. Due to the intrinsic structure of the questionnaire, only women who had children under 5 years old were included, a total of 20,245 participants. In our study, we focus on 2918 children who had diarrhoea in the last 2 weeks. Of that group, 292 participants were excluded due to missing values in maternal age, child age, sex of the child, marital status, maternal educational attainment, maternal smoking status, maternal alcohol use, wealth index, children’s health insurance, residence region, dyspnoea in the last 2 weeks, fever or cough in the last 2 weeks, seeking advice or treatment for diarrhoea in the last 2 weeks, Oral Rehydration Salts (ORS) or oral zine use, and type of services accessed for diarrhoea. The final analyses included a total of 2626 individuals.
Measurement and data collection
Predisposing characteristics (P) are personal characteristics that exist prior to the onset of specific episodes of illness. In this study, P included age, sex, marital status, and maternal educational attainment as they have been previously used in studies examining risk factors for healthcare utilisation. Our study also included other factors such as children’s number in a household, smoking status, and alcohol use as they are often considered in studies using the BM. Age was a continuous variable, while the six others were categorical variables: sex (girl/boy), marital status (married/cohabiting/not married), maternal educational attainment (no formal school, primary school, junior high school, senior middle school, senior high school and above), children’s number in a household (1-13), maternal smoking status (yes/no), and maternal alcohol use (yes/no).
Enabling resources (E) are factors that make health services resources available to the family. In prior studies, the most commonly used variables in the category were income and financial situation. The current study attempted to capture E by examining five variables: wealth index (0-10), health insurance (yes/no), residence region (rural/urban), improved water sources (yes/no) and improved sanitation facilities (yes/no). The use of a wealth index is generally considered an accurate mechanism to determine socioeconomic status (SES) within a population [37, 38]. The wealth index [39], which captures underlying long-term wealth through household asset information, was constructed by principal components analysis using the information on ownership of consumer goods (e.g. refrigerators, televisions, cars, trucks, bicycles, and motorcycles), materials used in household construction (e.g. wood, bricks, rocks, and cement), household electricity, access to drinking water and water for general use, and improved sanitation facilities [36, 40]. Therefore, individuals’ SES was determined through the wealth index. Drinking water sources are defined as improved drinking water sources (piped water, boreholes or tubewells, protected dug wells, protected springs, rainwater, and packaged or delivered water), and unimproved sources (unprotected springs and wells, surface water, and other sources) [41]. Improved sanitation facilities are those designed to hygienically separate excreta from human contact (Flush/pour flush toilets connected to piped sewer systems, septic tanks or pit latrines; ventilated improved pit latrines, composting toilets or dry pit latrines with slabs), while unimproved sanitation facilities (Pit latrines without a slab or platform, hanging latrines or bucket latrines and open defecation). Improved and unimproved water sources or sanitation facilities were represented as dichotomous variables, with “1″ representing “unimproved” and “2″ representing “improved”, respectively for both water sources and sanitation (Additional file 1: Table 1) [32].
We measured children’s health needs (N) by using the following common factors that impacted the possibility of healthcare-seeking behaviour, including fever (yes/no), cough (yes/no), dyspnoea (yes/no), and eating less (No, eating more/Same as before/Yes, eating less) in the last 2 weeks.
Four variables were used in this study to quantify children’s healthcare usage for diarrhoea: seeking advice or treatments for diarrhoea in the last 2 weeks (yes/no), the type of services accessed for diarrhoeal health issues (including 16 items, the options given for “where did you seek advice or treatment?” were classified as the public health sector, private health sector, other sources, and none (Additional file 1: Table 1) [42], ORS use in the last 2 weeks (yes/no), and oral zinc use in the last 2 weeks (yes/no).
Data analysis
Structural equation modelling (SEM) was conducted using SPSS AMOS, version 24 (IBM-SPSS, Chicago), to validate the hypothesized direct and indirect associations among individual characteristics, health services quality contextual factors, and healthcare-seeking behaviours. To determine whether the relationships among the latent variables constructed were as suggested by BM, a confirmatory factor analysis (CFA) was conducted. Guided by the BM, four latent variables were examined: predisposing characteristics, enabling characteristics, health needs, and health services use for children with diarrhoea.
In addition to the chi-squared test (χ2), the goodness of fit index (GFI), the adjusted goodness of fit index (AGFI), and the comparative fit index (CFI) were examined. In all cases, the values ranged from 0 to 1 and reflected the improvement in the fit of a hypothesized model over a model of independence among the measured variables, with values over 0.95 indicative of a good fit. Eventually, the root means squared error of approximation (RMSEA) was used as a measure of model fitness per degrees of freedom, with values less than 0.06 considered desirable.