Horizontal inequities in the uptake of hHorizontal Inequities in the Uptake of Hospital Delivery and The Role of Social Determinants in China

Objectives: To measure the horizontal inequity in the uptake of hospital delivery and quantify the contribution of various social determinants of health (SDH) to such inequity in China from 1993-2008 Methods: With four national representative surveys in China conducted in 1993, 1998, 2003 and 2008, we measured horizontal inequity in the uptake of hospital delivery using indirect standardized concentration indices (CIs). By decomposing Cis into components, we explored the contributions of income, health insurance, education, living conditions to such inequities. Oaxaca type decomposition was further used to explain the role for each SDH on the changes of inequities between 1993 and 2008. Results: We found that horizontal inequity in the coverage of hospital delivery approached equal line in the urban areas and shrank by 90% in rural China in 1993-2008. The data also showed that dramatic socioeconomic achievement was made across the 16 years, including education, income, health insurance and living conditions, which contributed substantially to the reduction of the inequities in the uptake of hospital delivery. Income’s contribution was mainly made by its protection effect, while health insurance’s role was mainly played by its equal distributions in the rural areas. Conclusions: The horizontal inequity in the uptake of hospital births vanished in urban China and decreased in the rural. The leading contributors to such inequity were income, health insurance, living conditions and education. Decomposition analysis suggests that more investments are warranted for financial risk protection and targeted demand side subsidies may make a difference. DOI : 10.14302/issn.2381-862X.jwrh-15-801 Corresponding author: Xing Lin Feng, E-Mail: fxl@bjmu.edu.cn; Tel.: +86-10-8280-5394; Fax: +86-10-8280-2481.


Introduction
The widely cited concept of health equity is: "Equity refers to differences that are unnecessary or reducible and are unfair and unjust" [1] . Analyses on health care inequity were focused on the achievement of horizontal inequity, defined as "equal treatment for equal medical need, irrespective of other characteristics such as income, race, place of residence, etc [2]." A medicalized "downstream" paradigm focusing on risk factors was dominated [3] regarding the relationship between diseases and their determinants. More recently, however, an emerging revitalization of a broader perspective on "upstream factors" that determine population health and its potential value in helping solve health problems has gained traction [4]. This perspective focuses on factors such as cultural and social structures, socioeconomic status in one's family of birth and throughout the life course, and social and environmental factors, typically described as social determinants of health (SDH) [5][6][7]. The March 2005 launch of the World Health Organization's Commission on Social Determinants of Health [8] is a milestone of the recognition that there needs to be greater focus on those upstream determinants, followed by the Rio declaration [9] in reflecting a commitment among global health leaders to promote related policy actions. China has made great success in reducing maternal and neonatal mortality, which has been attributed to the national hospital delivery strategy [10,11]. In 1988 less than half of all women gave birth in hospital, yet twenty years later hospital births have become nearly universal, with the disparities shrank sharply between the poor and rich [12]. The effects of other various SDHs are also reported. For example, Xue et.al [13] and Wang et al [14] found that knowledge, culture, physical accessibility, education and parity were all correlated with the utilization of maternal health care in China, while Long et.al [15] reported rising utilization of institutional delivery after the launch of the Chinese New Cooperative Medical Scheme (NCMS). Say & Raine [16] made a systematic review on inequalities of maternal health care in developing countries, where age, education, medical insurance, clinical risk factors, distance of facility was found to be correlated with the uptake of care. However, none research has been performed to quantify the horizontal inequity for coverage of such care, nor did they analyse the contribution of various SDHs on the potential inequities in a unified framework.
With four national representative surveys in China conducted in 1993China conducted in , 1998China conducted in , 2003China conducted in and 2008 (10).
where the foot label k represent the k's SDH, t and t-1 stands by the two elapsed periods for comparison.
is the elasticity of x k to Y. By such decomposition we could partial out effects of the inequity in SDH and the effect of SDH on the inequity of Y, i.e. to answer that how much the change of Y's inequality over time could be explained as the inequality of each SDH per se, versus their protecting (damaging) effect on the inequity of Y respectively.
Non-linear models and the decomposition techniques require the projection linearly additive, for which we used the mean partial effects [28] as a linear approximation for (7) [29]. All the analyses were made using StataSE 9.2 and the "svy" sets of commands were used to take into account the sampling stratification and cluster effects.

Results
As Table 1 Table 2   years. Most strikingly income equivalent increased more than 6 times, illiteracy decreased near 4 times, hygiene increased 10 times and health insurance coverage increased by 9 times to near universal coverage, particularly for the rural.
We found that most of the inequity in hospital delivery coverage could be explained by household income. It is not surprising since we ranked household by their income to estimate the concentration indices.
But interestingly, we found that the contribution of income to the inequity in hospital delivery was mainly made by its protection effects rather than by income's own distribution. Such findings suggest that should women have money to pay for their care in hospitals, no matter how unequal their household income levels are, they would tend to use hospital delivery. Therefore care specific demand side finance may be more effective than wide social protection programs. For that targeted demand side finance approaches like delivery vouchers [30,31] , delivery fee exemptions [32], and conditional cash transfers [33] are all possible effective policy alternatives, with the last two approaches probably more effective, as proposed by the diagonal health system strengthening approach [34]. Meanwhile, the results also sheds light that it is the ability to pay rather than   Secondly, the data in this study are nationally representative and the sample size is large. As reported previously, response rate was higher than 90% [40].
With sampling procedures fully taken into account we believe that the analysis yielded robust national estimates, though there may be some limitations. Births not approved by the family planning system or among rural migrants temporarily away from home may have been missed. Since these women may be less likely to