Application of geographic information systems to the analysis of private dental practices distribution in Western Australia.

INTRODUCTION

Western Australia (WA), Australia's largest state, consists of approximately one-third of the country's landmass and has a population of approximately 2 million people. However, over 85% of this population live in a handful of urban centres with the majority (1.6 million) living in the state capital, Perth. Healthcare provision in this complex environment is difficult and a clear understanding of the distribution of the population and health service suppliers is critical to understanding and addressing the problem. The vast majority (80% or more) of oral health care in WA is provided by private practitioners on a fee-for-service basis. Although previous studies have examined the macro-level distribution of dentists, this study utilized a high acuity examination to examine the distribution of private dental practices in WA, especially in rural and remote areas.

METHODS

Dental practice locations were collected from open access sources and geo-coded. Population data were obtained from the Australian Bureau of Statistics and divided by census districts. The Index of Relative Socio-Economic Disadvantage (IRSD) was aggregated to census district level. Population and socio-economic data were then geo-coded using ArcGIS v9 (ESRI; Redlands, CA, USA). With Perth primary post office used as a central datum point, a sequence of maps at differing magnification was overlayed with a grid of latitude and longitude lines, or graticules.

RESULTS

Of the 602 dental practices mapped, 75% were within 32 km of the Perth General Post Office, and 95% were within 256 km. In metropolitan Perth, fewer dental practices were located in areas that have residents of lower socioeconomic status and the density of distribution of these practices was greatest in the inner city region.

CONCLUSION

This study highlights the complex nature of providing care to irregularly distributed populations in economic environments that are driven by factors not purely related to disease burden.