Using Geographic Information Systems (GIS) to Assess Outcome Disparities in Patients with Type 2 Diabetes and Hyperlipidemia

Objectives: Geographic information systems (GIS) tools can help expand our understanding of dispari-ties in health outcomes within a community. The purpose of this project was (1) to demonstrate the methods to link a disease management registry with a GIS mapping and analysis program, (2) to ad-dress the challenges that occur when performing this link, and (3) to analyze the outcome disparities resulting from this assessment tool in a population of patients with type 2 diabetes mellitus. Methods: We used registry data derived from the University of California Davis Health System’s elec-tronic medical record system to identify patients with diabetes mellitus from a network of 13 primary care clinics in the greater Sacramento area. This information was converted to a database file for use in the GIS software. Geocoding was performed and after excluding those who had unknown home ad-dresses we matched 8528 unique patient records with their respective home addresses. Socioeconomic and demographic data were obtained from the Geolytics, Inc. (East Brunswick, NJ), a provider of US Census Bureau data, with 2008 estimates and projections. Patient, socioeconomic, and demographic data were then joined to a single database. We conducted regression analysis assessing A1c level based on each patient’s demographic and laboratory characteristics and their neighborhood characteristics (socioeconomic status [SES] quintile). Similar analysis was done for low-density li