Background
Inequality in health refers to the differences in health conditions, or access to health care between groups, such that one group is better off than another. Differences in health between socioeconomic groups are one of the major public health challenges worldwide [
1]. In China, for example, although average life expectancy is dynamically growing, inequalities in health still exist within the country due to ever increasing income disparity [
2,
3]. Therefore, measuring inequalities in health, especially the gap between economic groups, is important for health scientists and policy-makers to improve health equality [
4].
Studies conducted in high-income countries have indicated that socioeconomic inequality in the prevalence of chronic non-communicable diseases (NCDs) is the leading cause of inequalities in life expectancy and total mortality among the rich and the poor [
5‐
7]. The increased emergence of NCDs also has serious economic and public health consequences, especially in many low- and middle-income countries [
8]. In China, it is estimated that 80% of deaths and 70% of the disease burden are attributed to NCDs [
9]. The negative effects of aging, environmental deterioration, unhealthy lifestyles and diets, and China’s rapid industrialization and urbanization create considerable challenges for China’s public health [
10]. NCDs will become another significant public health threat if the trend continues.
Previous research has shown that socioeconomic status is the main determinant of chronic disease distribution in populations [
11,
12]. However, the association between the socioeconomic status and the chronic disease varies widely among regions and even between different periods in the same region. For instance, the distribution of cardiovascular diseases across the socioeconomic status spectrum has reversed over time from a higher prevalence among individuals with a high socioeconomic status to a greater prevalence among individuals of low socioeconomic status [
13,
14]. However, previous studies from China have shown a positive relationship between the prevalence of hypertension and diabetes and socioeconomic status [
15,
16]. A comparative work on socioeconomic and educational gradient of the prevalence of several common NCDs across eight European countries has found that most NCDs have a higher prevalence among the lower educated, but the relationship between the prevalence of NCDs and the economic status is highly variable for different types of NCDs and countries [
17]. The pattern of inequality in NCD prevalence in different countries or regions depends on the stage of their socioeconomic development and their health policies [
18].
Moreover, disparities exist not only in NCDs prevalence, but also in self-care, medication adherence, and preventive care which affect the outcome of NCDs [
19‐
21]. For instance, diabetic patients need to perform a complex set of preventive care tasks (e.g. self-monitoring blood glucose, using hypoglycemic drugs, changing eating habits) essential for controlling blood glucose and preventing complications and advanced-stage disease [
22]. Despite the relatively low cost of these preventive care tasks, in most countries, individuals from the economically disadvantaged groups and communities are more likely to die due to chronic diseases than their richer counterparts [
18].
Chinese government has recognized these challenges and responded to them. The new healthcare system reform, which was launched in 2009, is seen as a key step in efforts to address health inequalities in China [
23]. The government’s plan was to reinforce the health care system, specifically to support the primary health care and promote equity in diagnoses and access to treatment [
23]. Consequently, the basic public health package was designed to improve disease prevention and health care for vulnerable populations (e.g. elderly, women, children, and individuals with chronic health conditions) [
24]. In 2009, the government provided 15 Yuan per head (raised to 35 Yuan in 2013, and 50 Yuan in 2017, 1 US$ = 6.5 Yuan) to healthcare providers to deliver basic public health services [
25]. This package mainly included establishment of health records, health education/promotion, geriatric care, chronic disease management. Effective measures have been applied to the prevention, management and control of NCDs. However, whether preventive care measures associated with chronic diseases were widely used and equitable has not been sufficiently investigated, especially in the underdeveloped western region of China.
This study aims to examine the socioeconomic-related inequalities in the prevalence of NCDs and in the use of preventive care among middle aged and older adults in Shaanxi Province of China and to quantify the contribution of different determinants to the inequality.
Discussion
This study is the first to explore the socioeconomic-related inequalities in the prevalence of NCDs and the patient preventive care in Shaanxi Province, China, and further quantifies the contribution of several selected determinants toward these inequalities. Our results suggest a higher prevalence of hypertension and diabetes among the rich compared to the poor, and clear inequalities in the preventive care favoring the rich (i.e. adequate use of medication and monitoring of blood pressure/blood glucose) among individuals with hypertension or diabetes in Shaanxi Province, China. A decomposition analysis revealed that the inequalities in the prevalence of hypertension and diabetes and patient preventive care were mostly driven by differences in economic status and, additionally, by other socioeconomic factors (i.e. educational level, employment status, and urban or rural areas) and unobserved effects.
Our results reveal that the prevalence of hypertension and diabetes are concentrated toward economically advantaged groups. These findings are consistent with previously published literature on other regions of China based on self-reported physician-diagnosed data [
16] or anthropometric data (i.e. an oral glucose tolerance test and measurement of blood pressure) [
15,
40,
41]. Findings from some low- and middle-income countries also show consistent economic gradients [
42‐
44]. However, some studies, mostly from high-income countries, indicate an inverse economic gradient [
45‐
47]. Furthermore, a few studies have revealed that the association between socioeconomic status and the prevalence of hypertension or diabetes can change or even reverse over time, especially in low- and middle-income countries [
13,
14]. In China, which is now in a period of rapid economic growth and globalization, higher socioeconomic groups appeared to be at a higher risk of hypertension and diabetes, partly due to a westernized lifestyle leading to an unhealthy diet, physical inactivity, and obesity [
48]. The pattern of inequality in the prevalence of NCDs depends on the level of development of social, economic, and health policies [
18]. As such, this study provides a glimpse into the underdeveloped western areas of China, given the socioeconomic disparities in the prevalence of hypertension and diabetes.
For patients with hypertension or diabetes, strengthening the preventive care implies reducing complications and significantly improving their chances of survival and their well-being. However, our results indicate that, among individuals with hypertension or diabetes, clear inequalities exist in the preventive care favoring the rich. These results possibly support some previous findings that NCDs patients of low socioeconomic status are more apt to get worse outcomes [
18,
49]. Our results also identify several key socioeconomic variables associated with the preventive care for individuals with hypertension or diabetes. Economic status, level of education, employment status, and urban-rural areas are the key socioeconomic indicators for monitoring inequalities in the patient preventive care as demonstrated by previous studies, such as Yusuf et al. [
19], Carrieri et al. [
50], and Gopichandran et al. [
51]. A variety of social and cultural factors associated with an individual’s socioeconomic status have an impact on one’s health beliefs; in turn, these beliefs can be vital for determining the use of preventive care [
52].
Our study has not identified a significant correlation between basic medical insurance and the preventive care for patients with hypertension or diabetes, even though studies from other countries have suggested that implementation of universal health insurance could be an effective way to improve treatment rates among those with chronic conditions and to reduce socioeconomic gradients [
18,
20]. In China, because of limited financing, the basic medical insurance is primarily oriented toward inpatient care, outpatient care for catastrophic diseases, and chronic disease-created complications. As a result, the effectiveness of the basic medical insurance in increasing preventive care for patients with NCDs could be limited. Encouragingly, the basic health insurance has advanced toward the tendency of extending its coverage to general outpatient care and more types of NCDs, which may reduce the inequality in patient preventive care to some extent. The effect of China’s basic medical insurance on the use of preventive care among NCDs patients will require further extensive studies.
The basic public health package launched in 2009 is quite likely to help decrease inequalities in diagnosis, preventive care, and outcome for patients with NCDs in China. Previously published studies from other countries have shown that universally accessible primary care helps to achieve glucose control and reduce complications in diabetics [
53]. In recent years, Chinese government has provided continuous financial support for primary healthcare institutions to offer public health services. For instance, for elderly people, the government provides a free physical exam every year, guidance on self-care/self-help, and injury prevention; for hypertension patients, the government provides at least one free follow-up visit every three months which includes health evaluation, syndrome surveillance, behavioral intervention, guidance on the use of medicines, and health education; similarly, for diabetes patients, the government provides free blood glucose tests every three months and other visiting services [
25].
Strong policies and programs should be considered to address inequalities in the prevalence of NCDs and in secondary prevention in patients already suffering from NCDs. Our findings suggest that economic status is the main source of inequalities in the prevalence of NCDs and in secondary prevention. For patients living with chronic conditions, economic obstacles may deter their use of preventive care and further affect the outcome of the chronic disease; in turn, increasing medical expenditures can worsen a family’s economic situation, reducing them to poverty.
Although China has made considerable progress in universal healthcare and primary healthcare, several challenges remain. Firstly, the basic medical insurance system should further expand the scope of reimbursement to remove economic barriers to access health care by enrollees with chronic conditions and to reduce the economic burden on NCDs patients. Powerful policies have been adopted in the public health package, but it is estimated that the basic public health package covered only a half of the elderly population aged over 65 years (57.1 million) and about one-fifth of the patients with hypertension and diabetes (35.5 million patients with hypertension and 9.2 million patients with diabetes) in 2010 [
23]. Hence, secondly, primary health care and public health services should be strengthened and cover more of the target population, especially the disadvantaged communities, to improve early detection and treatment through public education and interventions. For example, Farzadfar et al. have introduced a successful program in Iran’s primary health care system for controlling and managing hypertension and diabetes [
53]. Thirdly, it is equally essential to improve the physical accessibility of primary care and enhance the quality of health services, especially in rural areas. Implementing high quality and equitable primary care and ensuring availability and low cost of medicines essential for prevention and early treatment of NCDs are examples of effective ways to reduce NCDs burdens and inequalities [
18].
This study has several limitations that must be acknowledged. Firstly, the prevalence of hypertension and diabetes may be underestimated due to the self-reported physician-diagnosed format, which could affect the magnitude of inequality if the misdiagnosis mostly exists in the poor. However, hypertension and diabetes are less likely to be underestimated compared to other chronic diseases, because they are the focus of public health policy in China. That is, the government has offered continuous financial support for the primary health care for urban and rural residents to diagnose and prevent hypertension and diabetes. Moreover, our results on the relationship between the economic status and the prevalence of self-reported hypertension or diabetes are consistent with other findings based on anthropometric data for individuals in other regions of China [
15,
40,
41,
48]. Despite the limitations of self-reported diagnoses, this study can build an evidence base for understanding the socioeconomic-related inequalities in the prevalence of hypertension and diabetes. Secondly, in order to obtain a representative sample at a lower cost, a complex sampling technique was conducted to select the survey respondents. The complex sampling design complicates the estimates. Thirdly, for binary health variables, the use of C captures the magnitude of the socioeconomic-related inequalities across the entire socioeconomic spectrum but without considering the upper bound of the variable. Fourthly, recall biases are inevitable in questionnaire-based surveys, especially those pertaining to behaviors several months prior to the survey. Nevertheless, these large survey data sets enable us to identify socioeconomic-related inequalities in preventive care for patients in the underdeveloped western areas of China. Future studies should focus on monitoring the changes in the inequalities in the prevalence of NCDs and their preventive care and on assessing the effectiveness of health policies in mitigating these inequalities.
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