According to the 2010 census, Alabama has approximately 960,000 women of child-bearing age, which we define as 15–44 for the purposes of this study. This is the population of interest to us, and our general goal is to measure access by this population to obstetric services, particularly the portion of the population in rural areas. Here are some statistics of interest:
The types of resources of interest to us are hospitals that provide obstetric services, which we will refer to simply as OB hospitals, and physicians that provide obstetric services, which we will refer to as OB physicians.
Alabama has 91 general admission hospitals, but only 49 offer obstetric services. Of the 49 OB hospitals, 31 are in urban areas and only 18 in rural communities. The American Congress of Obstetricians and Gynecologists (ACOG) classifies OB hospitals into three levels in terms of the nature of the obstetric and neonatal care that can be provided:
Alabama's OB hospitals do not fully adopt the ACOG classification, but we can summarize generally. Only Alabama's five largest cities have Level 3 OB hospitals: Birmingham, Huntsville, Mobile, Montgomery, and Tuscaloosa. Most of the OB hospitals located in Alabama's other urban cities (such as Anniston, Decatur, Dothan, and Gadsden) are Level 2. Generally, the rural OB hospitals are all Level 1.
Alabama has about 440 physicians who provide obstetric services. Most of the OB physicians are OB/GYNs, but a few are family physicians. Only about 50 of the OB physicians are in rural areas. Indeed, most of the OB physicians are in wealthy urban areas such as Birmingham, Huntsville, Mobile, Montgomery, and Tuscaloosa.
There are two general questions that need to be considered to measure access.
Question 1 deals with geographical access. Access to an OB hospital can be classified roughly in terms of drive time:
Question 2 deals with medical access. ACOG classifications regarding the ratio of OB physicians per 10,000 women are as follows:
Traditionally, counties have been the geographical units used to measure health outcomes and access to medical care in the United States. Alabama has 67 counties of which 39 are classified as rural and 28 as urban. Of the 67 counties, only 29 have OB hospitals and only 14 of the 39 rural counties have OB hospitals. Nonetheless, the 29 counties with an OB hospital contain about 75% of the population of interest. The remaining 25% of the population (approximately 240,000 women) are all in rural locations. Each county with an OB hospital has enough OB physicians to serve the population of that county at the minimal level, and all but one at the acceptable level.
But counties are geo-political entities, and are artificial as healthcare service areas. Typically, a woman would not choose an OB hospital in her county (even if one exists) if there is a closer OB hospital in a neighboring county. Similarly, many women in a county with an OB hospital are too far away from the hospital for proper medical access, as defined above.
Our approach in this study is to define service areas centered on the hospitals in Alabama that offer obstetric services. For that purpose, we define a centroid as a an OB hospital, or the case of certain urban areas, a cluster of two or more OB hospitals in close proximity. We then use Geographical Information System (GIS) software to construct a service area around each centroid. The service area of a centroid consists of the portion of the state that is closer to that centroid than any other (as measured by the road network) but limited to a specified driving time. Our GIS software has full information about the road network in Alabama (type of road, speed limit, etc.) and so can accurately construct such service areas. We constructed three sets of service areas, corresponding to 20-minute, 30-minute, and 60-minute drive times.
The software also contains the full 2010 census data and so can also compute the population of women of child-bearing age in each service area. Finally, we also have data on the location of the approximately 440 OB physicians in the state and so our GIS software can assign each such physician to a centroid.
Our data are displayed in the form of interactive maps and interactive tables. The maps generally have point or area layers that can be added or removed with the layer control on the map. The user can zoom in and out of a map and move about in the usual way. Zooming in reveals additional features such as small towns and then streets and roads. A click on the home button returns the map to its origional location and scale. The zoom -to-area button allows the user to zoom to a selected rectangular area of the map. Clicking on an object in a layer shows summary data for that object.
The interactive tables can be sorted by any field, by clicking on the header for that field. The buttons at the top allow the table data to be copied to the clipboard, in tab-separated text format, printed, or downloaded in various formats (tab-separated text, Excel, or PDF). With the search bar, the table can be filtered according to a text string.
In the interactive tables that display area data (counties amd drive bands) you can click on a row to select an area and see the area highlighted in the map. You can select as many areas as you wish. Click on a selected area again to de-select and remove the highlight.