Unequal treatment: challenging socioeconomic and living area disparities in oral rehydration therapy and continued feeding in 35 Sub-Saharan African countries


 Background While the 2030 global goal has motivated proliferation of equity-oriented studies globally, we did not find sweeping studies on disparity in Oral Rehydration Theory (ORT) and continued feeding at the level of the Sub-Saharan Africa (SSA) region. Yet, exploring the within and between-country variations of the service could help synthesize useful policy lessons that can be applied to other settings within the region. We aimed to generate evidence on inequality in use of the service at the level of SSA in order to suggest the way forward to advance the momentum already gained in the region with respect to improving coverage of this lifesaving interventions. Method We applied the World Health Organization’s Health Equity Assessment Toolkit for the analysis. Data were obtained from Demographic and Health Surveys conducted between 2012 and 2016. Thirty-five countries were selected from different income categories in SSA. ORT and continued feeding disparity was analyzed with respect to five dimensions of inequality (wealth, education, sex, residence and subnational regions) through four measures of inequality: difference, ratio, population attributable risk and fraction. Results Disparity in use of ORT and continued feeding plagued SSA and consistently favored advantaged population subgroups. In 20 out of 35 countries, the service was disproportionately concentrated among children from well to do households. The inequality was strikingly pronounced in Angola, Guinea, Cameroon and Mali. We also recorded sizable variations with respect to residence and education in 23 and 11 countries. Interestingly, male and female children get the service almost equally in most countries, with only four countries (Niger, Kenya, Guinea-Bissau, and Senegal) suffered sex differentials, generally to the favor of male children. Conclusion In SSA, unjustified disparity around use of ORT and continued feeding is a pervasive problem that requires resolute policy response soon. Eliminating the disparity would set the region miles ahead to reaching the child health related global goals to be attained in 2030. The region might benefit from equitable economic and education policies.

literatures, we found that studies that discuss the situation of disparity in use of ORS and continued feeding among children with diarrhea in SSA are lacking. WHO examined the state of inequality in ORT in several countries of low income and middle income using data collected through DHS conducted until 2013 (11). However, we signi cantly updated the available evidence by incorporating data from more recent DHSs. The study aims to generate high quality information on status of ORT disparity in SSA and put the way forward about the possibility to challenge the unacceptable disparity. The evidence could be of help to identify subgroups of a population that require big policy attention and in so doing would potentially lead to attainment of ensuring universal reproductive, maternal and child health care target of the 2030 SDG. Selection of the countries in our analysis was partly based on the fact that, they are from different country level income categories (low income, lower middle and upper middle income), and this could allow us to benchmark the disparity situation in one country in a speci c income category to that of another nation in a different income category. This in turn facilitates interpretation of state of inequality in ORT in a way that could potentially lead to emergence of policy relevant suggestions. Also, we included the DHSs carried out between 2012 and 2016, as DHSs conducted until 2013 were analyzed by the WHO as mentioned in the background; we continued from where previous high quality study ends.

Data
DHS is a nationally representative household survey conducted at regular time intervals to provide countries with updated information on a different health topics such as maternal and child health, reproductive health, fertility, nutrition, mortality, and HIV/AIDS to mention just a few. The United States Agency for International development (USAID) and each country's statistical agency cooperate to run the survey with technical support from Inner City Fund (ICF) international.
Method of DHS has been described in detail in the nal DHS report of each country and readers can read relevant sections of the respective countries' DHS report to learn the methodology. Concisely, it follows a two stage strati ed cluster sampling design. Big geographic areas like enumeration area (EA) are selected in the rst stage though Probability Proportional to Size (PPS) approach (citation), where relatively larger EA is more likely to be selected than smaller EA. In the second stage, a pre-calculated (28 to 30) number of households are selected from each EA. In the selected household, eligible participants (women aged 15 to 49 years and men 15 to 59 years) interviewed on wide range of areas using questionnaires that are comparable across countries. To capture some useful information on health topics that would be of relevant in a country only, country speci c questions are also included in the model questionnaire. The similarity of the methodologies in all the DHS makes it easy for sound comparison of ndings across the 35 countries.

Variables
We measured inequality for ORT and continued feeding in under-ve children with diarrhea. ORT and continued feeding is the the percentage of children age under-ve who had diarrhea in the two weeks prior to the survey and were treated with ORT, oral rehydration salts or any appropriate solution prepared in household. A child is said to have diarrhea if he/she has passage of three or more loose or watery stools per day (12). The ORT and continued feeding was calculated for the children who were born ve years prior to the respective surveys. We disaggregated utilization of ORT and continued feeding using ve dimensions of inequality which included wealth (economic status), education, residence, region and sex. While educational status is classi ed as no education, primary and secondary education, wealth index is classi ed into ve categories: poorest, poor, middle, rich and richest. In all the DHSs, wealth index has been used as proxy for economic status and is computed based on household assets and possessions using a statistical technique called Principal Component Analysis (13). Residence is a binary variable classi ed as urban vs. rural and sex as male and female. Sub-categories of a region differ based on where which country the study is done. See Tables 6 in the result section for detail on this.

Statistical analysis
We approached investigation of the inequality in utilization of oral rehydration therapy and continued feeding in two steps. First, we disaggregated utilization of ORT and continued feeding by the aforementioned equity strati ers. This is a preliminary, but critically important step to correctly interpret ndings obtained through summary measures in the later stage of our analysis. Again as part of the rst step, we also presented the population share of each subgroup alongside their respective coverage of the health indicator; this is very important in the interpretation of uncertainty intervals of point estimates.
Secondly, we analyzed the inequality in oral rehydration therapy and continued feeding through calculation of four measures of inequality: Difference, Population Attributable risk (PAR), Ratio and Population Attributable Fraction (PAF). When we interpret ndings produced using any of these measures, we feedback to the rst step to check how the summary was estimated.
Detailed account of the methods followed in this study have been found elsewhere (10,14). PAR is calculated as the difference between the estimate for the reference subgroup y ref  D is calculated as the difference between two subgroups: D = y high -y low . For binary dimensions (residence and sex for our study), y high refers to the subgroup with the highest estimate ( urban and male) and y low to the subgroup with the lowest estimate of ORT and continued feeding ( rural and female). For ordered dimensions (wealth and education for our study), y high refers to the most-advantaged subgroup (richest and secondary education) and y low to the most-disadvantaged subgroup (poorest and illiterate group). For subnational region, y high refers to the subgroup with the highest estimate and y low to the subgroup with the lowest estimate. The calculation of R parallels that of D except that it is a ratio of two estimates instead of subtracting one from another. WHO's HEAT software. We accessed the latest o ine version of the application from internet, and did the analysis and interpret ndings in accordance with equity analysis principles contained in the WHO health equity analysis book (10).

Ethical Consideration
Ethical permissions are not required for this study since we used DHS datasets already publicly available. Ethical procedures were the responsibility of the institutions that commissioned, funded, or managed the surveys. All DHS surveys are approved by ICF international as well as an Institutional Review Board (IRB) in respective country to ensure that the protocols are in compliance with the U.S. Department of Health and Human Services regulations for the protection of human subjects.

Results
Wealth based inequality Table 1 presents utilization of ORT and continued feeding for each subgroup of the economic status strati er across the 35 low income, lower middle income and upper middle income SSA countries along with the population share of each. In the vast majority of the studied countries, ORT and continued feeding is higher among the richest subgroups. There are also few countries with disproportionately higher coverage in quintiles 3 and 4. For instance, in Mozambique and Lesotho, the average coverage among quintile 4 is higher than among quintile 5. In the other few countries, coverage is higher among the poorest subgroup than among the richest subgroup. For instance, the coverage is, on average, higher among the poorest subgroups in Togo, Namibia, Gabon and Eswatini (  the average coverage is higher among the primary group. In Rwanda, we observed unusual concentration of the service, where the coverage is highest among no education, followed by primary and secondary. In the remaining countries, it is higher among children born into women who completed the secondary education (Table 3).

Sex Inequality
Without calculating summary measures, in 19 (54%) of the countries, the average coverage of ORT and continued feeding is higher among male children than among female children (Table 5). According to the summary measures, however, we saw sex inequality in Niger, Kenya, Guinea-Bissau, and Senegal only (Table 6).  Residence Inequality The present study shows that out of the 35 countries, in twenty six of them, the average coverage of the ORT and continued feeding is higher among urban residents as compared to the rural residents. However, in Algeria, Burundi, Eswatini, Gabon, Sao Tome, Benin, Gambia, Senegal and Togo, at least the point estimate is higher among the rural than among urban residents ( Table 7).  Tome, Sierra Leone, Togo and Senegal, we did not record any urban-rural inequality. Sub-national Regional Inequality Table 9 shows signi cant regional disparities in the utilization of ORT and continued feeding in the SSA countries. We recorded within country subnational regional disparities in the service in the studied countries, albeit the extent of disparities varied by country. With the exception of Comoros, Gabon, Rwanda, Sao Tome and Sierra Leone where no regional inequality was observed, other countries saw regional inequality with at least one measure. In Burundi, Cameron, Democratic Republic of Congo, Eswatini, Ethiopia, Guinea, Guinea Bissau, Kenya, Mali, Mauritania, Niger, Nigeria, Senegal, Togo, Uganda, Zambia and Zimbabwe, both absolute and relative regional inequality were demonstrated by all the four measures. The magnitude of regional inequality varied based on the measures of inequality. For instance, based on the PAF measure, the average regional disparity was highest in Ethiopia (105.2%) followed by Ghana (80.1%) and Mali (67.2%). By the Difference measure, the highest were in Guinea Bissau (59.6%) followed by Ghana (53%) and Angola (51.3%). See Table 10.  Table 10 Sub-national regional inequality in ORT and continued feeding in the 35 low income, lower middle income and upper middle income SSA countries  (4).The SDG underscores policy implications of disaggregating health care indicators by dimensions of inequality such as wealth and place of residence. To this end, ndings presented in this paper could contribute to the design of equity interventions in order to minimize the observed disparity in one of the most imperative child health care indicators, ORT and continued feeding.
We recorded substantial wealth-related disparity in 20 countries. The disparity was highest and more pronounced in few countries such as Angola, Guinea, Cameroon and Mali. Based on the PAF measure, we showed that the coverage for ORT and continued feeding in 2013 in Nigeria would have been increased, on average, by a staggering nearly 62% if the country had avoided the poor-rich disparity of the service. This translates to a rise of the coverage from 29-47%. In other words, the coverage gap would have dropped from 71 pp to 53 pp. Such big rise in the coverage would signi cantly have helped the country attain the global goal of universal coverage in maternal and child health care service. Angola, Guinea, and Cameroon each had average wealth related disparity between 24%-52%, and as is the case discussed for Nigeria above, their respective national coverage for ORT and continued feeding would have considerably risen if they were able to avoid the observed disparity. Although income disparity in SSA has received greater attention by the SDG (4), there are income disparities that persist still today in the region. In fact, SSA is one of the most unequal regions in the world in terms of income distribution between people (5). Thus, since income is the basis for living, accelerated reduction of poverty in the region could be translated into attaining the other SDGs (5). However, extent of income variations differed by countries in the region. Nigeria is one of the most unequal countries in the region (15), and the disparity continues to cause disparities in health care use like ORT and continued feeding. When there is economic disparity in a nation, already wealthier people are likely to bene t more from the economic growth whereas poor people are left behind with little gains (15). An economic growth would bene t wider public including the poor when countries are of more equal (15). Policies need to focus on correcting the stark income inequality between peoples to rescue poverty related health loss. Due to the fact that income and health have a wellknown close nexuses, equitable economic policy must be regarded as health policy (16), in order to confront the steady economic gradient in health. The mechanisms by which income can exert its in uence on health and health cares have been studied (17). One of the possible mechanism through which income affects health and health care is that it increases people's chance of being covered under insurance, and for low-income people, this scheme enhances their means of accessing medical care (17).
In 2018, an estimated 27.9 million people were not under insurance coverage in America (18). Since larger share of uninsured people are disproportionately low income families (19), economic policy targeted towards economically lagging households should consider expanding coverage of insurance service.
We also showed educational inequality in ORT and continued feeding in eleven countries: Angola, Benin, Burundi, Cameron, Chad, Guinea, Guinea Bissau, Kenya, Mali, Mozambique and Nigeria. While the disparity in all these countries requires more work to eliminate the inequality, some countries such as Chad, Guinea, Cameron, Nigeria and Mozambique had the highest average inequality. Had these countries avoided the absolute educational disparity in the use of ORT and continued feeding, then the national coverage of the health service in these countries would have been climbed by, on average, 10 to nearly 18 pp, and the rise in the national coverage would have been increased even more if they had avoided the relative disparity on average by between 26 and 41 percent. Secondary school participation has been most challenging in SSA and South Asia (20). In Chad for instance, more than 6 for every 10 adolescents do not join secondary school. More worse is that, there is striking gaps in level of secondary school participation between income groups, where only less than 50% of children from poor family are able to attend secondary school in contrast to 80% of adolescents from the richest household (20). Increasing the proportion of girls who graduated secondary education would greatly contribute to the ght against educated driven inequality in use of ORT and continued feeding in these countries. SSA is required to increase the total enrollments by more than 3 times than the current level if the aim is to attain universal coverage for pre-primary, primary and secondary education by 2030 (21). As an important component of socioeconomic status, education has long been known to in uence health disparities directly (22), but education is largely recognized as a legitimate domain of public health action, and is an in uential method to disrupt the vicious cycle of poverty. Moreover, education is an essential component of public health interventions that can be used to stimulate health equity and help overcome health disparities (23). Given the current low educational status in most SSA countries, integrating education into public health policies could lead to widespread bene t with respect to challenging health care disparities in the sub-region.
The other interesting nding of this study is that, the largest number of countries in the study did not see sex related disparity around ORT and continued feeding. In 2030, all countries globally are going to ensure gender equality with respect to health care, and participation in politics as well as economic sectors (4). Our study con rms that most SSA countries are likely to attain that goal with respect to this child health care intervention if they do maintain the current momentum. However, there are a handful of countries with slight sex disparity: Niger, Kenya, Guinea-Bissau, and Senegal. In the no sex disparity scenario, Niger would have elevated the coverage of ORT and continued feeding by, on average, 2.3 pp, and female children had a slight advantage over males in use of the service. In Kenya and Guinea-Bissau, on the other hand, male children had on average 6.4 and 11.3 pp respectively more chance of getting the service than female children. Similarly, male children had little but statistically signi cant advantage over female counterparts in Senegal with regard to receiving ORT and continued feeding. Governments of these countries may consider revising existing interventions in order to make the interventions more gender sensitive and responsive.
No urban-rural inequality was found in 12 of the studied African countries: Ghana, Benin, Burundi, Algeria, Eswatini, Gabon, Gambia, Namibia, Sao Tome, Sierra Leone, Togo and Senegal. In terms of subnational regions, ve countries (Comoros, Gabon, Rwanda, Sao Tome and Sierra Leone) managed to distribute the service fairly between different regions while the remaining countries had gaps in ORT and continued feeding between different regions. Rural settings and certain geographical areas tend to host rather few children with diarrhea that receive ORT and continued feeding. This further implies that the residence related and subnational regional variations could obstruct SSA countries from attaining of the SDG. To curb the predictable threat of the within country disparities, such countries need to revise existing child health interventions and promote more equitable interventions that target rural areas, poor and illiterate households, and certain geographical areas to accelerate elimination of unacceptable gap in ORT and continued feeding and in so doing could help countries attain the global goal of universal child health care (that is, ORT and continued feeding).
The study has some strength. Findings are produced following transparent and scienti cally sound equity analysis technique recommended by the WHO, making the results more reliable for use for decision making. Also, since different summary measures were used in the study, we are hopeful that the disparity was captured from different perspectives. This approach, the approach of adopting 'method-mix', could contribute to not conclude absence of disparity while there is in fact disparity and in doing so could lead to prevention of unsupported decisions. Finally, measuring disparity in ORT and continued feeding through ve dimensions of inequality has huge advantage of recognizing population subgroups that suffer lower coverage of the service; policy interventions will then be formulated that favors such groups. The limitation of the study is that, it just highlighted on the disparity of the service across different equity stratifers. However, to better ght against the disparity, it is important to understand the reasons that underlie the observed disparity. In this regard, we recommend future studies to answer this important research question using a decomposition analysis to examine independent contributions of factors that work behind the disparity in ORT and continued feeding.

Conclusions
In SSA, socioeconomic, urban-rural and geographical inequalities around ORT and continued feeding were substantial. Fortunately, except in a handful of countries, we did not record sex-related inequality in the use of the child health care in the studied countries. Countries need to intensify pro-disadvantaged interventions that target the poor, illiterate, rural residents and some living places in order to challenge the unfair distribution of the service and subsequently markedly decrease the unnecessary diarrheal deaths. Also, the SSA region may bene t more from widespread equitable economic and education policies as income and education have been shown to underlie health care disparities. This could eventually translate into attainment of the global goal of universal coverage for ORT and continued feeding by 2030.