Application of geographic modeling techniques to quantify spatial access to health services before and after an acute cardiac event: The Cardiac Accessibility and Remoteness Index for Australia (ARIA) Project

Background: Access to cardiac services is essential for appropriate implementation of evidence-based therapies to improve outcomes. The Cardiac Accessibility and Remoteness Index for Australia (Cardiac ARIA) aimed to derive an objective, geographic measure reflecting access to cardiac services. Methods and Results: An expert panel defined an evidence-based clinical pathway. Using Geographic Information Systems (GIS), the team developed a numeric/alphabetic index at 2 points along the continuum of care. The acute category (numeric) measured the time from the emergency call to arrival at an appropriate medical facility via road ambulance. The aftercare category (alphabetic) measured access to 4 basic services (family doctor, pharmacy, cardiac rehabilitation, and pathology services) when a patient returned to his or her community. The numeric index ranged from 1 (access to principal referral center with cardiac catheterization service ≤1 hour) to 8 (no ambulance service, >3 hours to medical facility, air transport required). The alphabetic index ranged from A (all 4 services available within a 1-hour drive-time) to E (no services available within 1 hour). The panel found that 13.9 million Australians (71%) resided within Cardiac ARIA 1A locations (hospital with cardiac catheterization laboratory and all aftercare within 1 hour). Those outside Cardiac 1A were overrepresented by people >65 years of age (32%) and indigenous people (60%). Conclusions: The Cardiac ARIA index demonstrated substantial inequity in access to cardiac services in Australia. This methodology can be used to inform cardiology health service planning and could be applied to other common disease states within other regions of the world.