Physicians

Shortage on Primary Care Physicians



Shortage on Primary Care Physicians

Introduction

Access to primary healthcare is recognized as an important facilitator of overall population health (Guagliardo, 2004) because primary care is the first line of defense for the population and a critical part of preventive care. Good primary care can prevent or reduce unnecessary expensive specialty care (Lee, 1995; Luo, 2004). To ensure adequate access to primary care, health service planners and policy makers need accurate and reliable measures of accessibility so that true physician shortage areas can be accurately identified and resources allocated to those needy areas to alleviate the problem.

Background on physician shortage designation in the US

Among the many factors that influence access to health care services, two of them are critical: physician supply and population demand. Both of these are spatially distributed, but it is rare that their distributions perfectly match (Luo, 2004). Health care access problems are especially pronounced, for example, in rural areas and impoverished urban communities (COGME, 2000; Rosenblatt and Lishner, 1991).

The US federal government spends about $1 billion a year on programs designed to alleviate health care access problems, including providing incentives or awarding financial assistance to providers serving designated shortage areas through the National Health Service Corps Program, the Medicare Incentive Program, and the J-1 visa waiver program, among others (GAO, 1995).

Measures of potential spatial accessibility

The problems of regional availability measures have been long recognized in geography (e.g., Openshaw and Taylor, 1981), but are still not well resolved. This is partially due to the complexity of the issue, i.e., both the supplies and demands are spatially distributed and are likely overlapping, and competition exists among suppliers and consumers (e.g., [Huff, 1963] and [Huff, 1964]).

The alternative to regional availability measures is the regional accessibility approach, which uses a gravity model formulation to factor interaction between supply and demand located in different regions with distance decay, thereby addressing the problems of the regional availability approach (Weibull, 1976; Joseph and Bantock, 1982; Joseph and Phillips, 1984; Shen, 1998; Huff, 2000; Wang and Minor, 2002; Guagliardo, 2004; Yang et al., 2006). The gravity model as applied to measure access to physician usually takes the following form:

Is the gravity-based index of accessibility at population location, where n and m are the total numbers of physician locations and population locations, respectively? The denominator term represents a measure of the availability of physicians at location j to all population (Pk, k=1, 2, …, m). Sj is the number of physicians at location j; dkj and dij are the distance or travel time, and ß is the friction-of-distance coefficient.

Methodology

Building on previous research, this paper presents an enhancement to the 2SFCA method by applying weights to differentiate travel time zones, in both the first step and the second step, thereby accounting for distance decay. In the following discussion, we assume that the population data is in the gridded raster format such as LandScan. The same principle applies to vector-based population data.

In order to differentiate accessibility within a catchment, multiple travel ...