Setting
Iran is an upper-middle-income country having a total population of about 80 million people inhabiting in the country’s 31 provinces, out of which 74% resides in the urban settings. The total number of all type services providing hospitals during 2016 in Iran was 921. Both teaching and non-teaching governmental (public), private, social security organization (SSO), military, and charity hospitals accounted for 568, 161, 74, 52, and 30, respectively. The remaining 36 were affiliated with other non-public organizations. A quarter (25%) of the total population lives in eight top largest cities namely Tehran, Mashhad, Esfahan, Karaj, Shiraz, Tabriz, Qom, and Ahvaz [
25]. This study purposefully included Tehran, Mashhad, Esfahan, Shiraz and Tabriz metropolitan cities, and are located in the northern, eastern, central, southern, and western parts of Iran. Their geographical distributions fairly represent the metropolitan cities in Iran. A summary of the total number of districts, populations, and total hospitals beds within each city is presented in Table
1.
Table 1
Summary of districts, populations, hospitals and hospital beds distributions by metropolitan city in Iran
Districts | 13 | 10 | 9 | 14 | 22 |
Total population (in number) | 3,001,184 | 1,558,693 | 1,565,572 | 1,961,260 | 8,693,706 |
Total hospitals | 39 | 29 | 40 | 36 | 162 |
Hospital beds |
Private | 1099 | 803 | 1026 | 689 | 7488 |
Public | 6769 | 4995 | 5488 | 5107 | 22,719 |
Total | 7868 | 5798 | 6544 | 5796 | 30,207 |
Study design and data source
We measured the inequality in the distributions of hospitals and hospital beds using different techniques in five metropolitan cities during 2016 in Iran. The dataset consisted of hospitals, hospital beds, populations, and residential floor area per capita for a total of 68 districts of the cities. We retrieved the data on total population and residential floor area per capita of the districts’ residents from the Statistics Center of Iran (SCI). The data on the number and geographical locations of the functioning hospitals in the districts and hospital beds for the year 2016 were obtained from the municipalities of the cities, the hospitals’ database, the Ministry of Health and Medical Education (MOHME) of Iran, and the National Cartographic Centre of Iran.
Variables
The total hospitals (both governmental, private, and other public organization affiliated hospitals) providing services in each district of the cities were included in the study. The number of hospital beds per 10,000 population [
26,
27] was the variable (indicator) used to measure the inequality of access to hospitals. Nevertheless, the residents are more likely to form and maintain a system of social stratification along multiple dimensions including socio-economic status [
28]. The most commonly used socio-economic status (SES) indicators in health care research are educational status, income, wealth, housing condition with its location, overcrowding (residential density), etc. [
28‐
33].
The area level SES indicators are useful not only to characterize the extent of inequality in resources distributions but also as a measure of the SES of individuals. For example, overcrowding (> 1 person in a room) often implies few economic resources of the household [
29,
34]. Therefore, our analysis applied residential floor area per capita (m
2/person) to measure the socio-economic inequality in hospitals and hospital beds because there was no data on income per capita of the people. Despite income per capita is a direct measure of SES [
28], the residential floor area per capita is a comprehensive indicator of the economic, social, cultural, and environmental dimensions of people living in a given urban area [
35,
36].
Analysis and interpretation of inequality
In this analysis we categorized the hospitals into public including the SSO hospitals, private, and other ownership hospitals such as military, charity, etc. The descriptive analysis and the mapping of the geographical locations of hospitals using the Geographic Information System (GIS) were based on all 306 hospitals. The inequality measures were based on the public and private hospitals, and the unit of the analysis was district. We applied different methods of analysis and characterized the distributions using the district level data of five metropolitan cities in Iran. First, we used the administrative boundaries of the districts as reference points for identifying the locations of the hospitals and residential areas. Then, the hospitals were mapped against the floor area per capita of the residents using the Geographic Information System (GIS) in QGIS 3.8 software to have an insight about the geographical locations of the hospitals with respect to the SES of the residents [
37,
38]. The QGIS is an open source software for mapping spatial data. The natural break [
39] was used to categorize and display the categories of the residents’ access to hospitals against their SES, and the output maps have been illustrated using the QGIS.
Second, we used the Gini and concentration indices to measure the inequalities in the distribution of the hospital beds. The Gini index (GI) is a standard measure of distributional inequalities in healthcare with respect to population size and has a direct relationship with the Lorenz curve [
26]. It is an important measure when the fairly aggregated distributions involve relatively few and large geographic units and is mathematically described as [
40]:
$$ GI=1-{\sum}_{i=1}^{k-1}\left({Y}_{i+1}+{Y}_i\left)\right({X}_{i+1}-{X}_i\right) $$
Where Y, is the cumulative proportion of hospital beds per 10,000 people over k districts, and X is the cumulative proportion of the population ranked by floor area per capita.
The Gini values range from 0 (perfect equality) to 1 (perfect inequality). Despite the degree of the Gini inequality is context specific and may be interpreted in different ways, our analysis interpreted the extent of the inequality based on the five scale values categorized as absolute equality (GI < 0.2), high equality (GI = 0.2–0.3), inequality (GI = 0.3–0.4), high inequality (GI = 0.4–0.6], and absolute inequality (GI > 0.6) [
26,
41].
We further applied the concentration index (CI) to measure the socioeconomic inequality of hospital beds distributions [
7]. The CI can be defined as twice the area between the concentration curve and the 45-degree line of equality, and highlights the extent of unfair inequality which is amenable to policy or action [
42,
43]. The CI can be calculated the same way as the GI but the value always lies in the range [− 1, + 1]. The values of CI < 0, CI = 0, and CI > 0 indicate the disproportionate concentration of the distribution in favor of the poor, proportionate distribution, and disproportionate concentration of the distribution in favor of the rich, respectively. The more the value deviates away from 0, the higher is the inequality [
43,
44]. The Gini and concentration indices were calculated using the latest official Stata command “
conindex”. This command provides the inequality measured value with its standard error and
p-value, and is an appropriate estimate of the rank-dependent indices of univariate inequality [
43].
Finally, correlation analysis was performed to show the relationship between public, private and total hospital beds distributions and residential floor area per capita for each metropolitan city. The analyses were done using the statistical software package STATA 13 and considered significant at p-value less than 0.05.