The relationship between potential spatial access and revealed access to hemodialysis facilities in northeastern Iran

Background:To survive, hemodialysis patients need to travel from their house to dialysis centers at least three times a week Patients’ poor access to dialysis facilities is significantly associated with the high rate of mortality and lower quality of life. Geographic Information System (GIS) for measuring access to dialysis facilities have drawn attention as a point of research in recent years. Access has five main dimensions; accessibility, availability, accommodation, affordability, and acceptability. Accessibility and availability both together reveal potential spatial access. The objective of the present study was to measure the relationship between potential spatial access and revealed access to hemodialysis services in the geographical region of North Khorasan province of Iran using census tract as small area level.Material and Methods:Two researchers visited all dialysis centers in North Khorasan province and interviewed 165 participated patients using the structured questionnaire without sampling in winter of 2015. This study was approved under the code IR.MUMS.RES. 1393.756 by the Ethical Committee of Mashhad University of Medical Sciences. The interview information included residence addresses and their self-reported travel times to dialysis centers. We used the self-reported travel time for calculation of revealed access. Moreover, we collected information on the number of active hemodialysis machines in each dialysis center and their service profiles. The geocoding tasks were performed using Google’s Geocoding Web Service. The census tract level was used as the basic spatial unit for measuring spatial access to dialysis services. The Dialysis Guideline recommends the maximum distance of 40 KM as the appropriate range for dialysis patients. We used this guideline to define the proper radial coverage distance for every dialysis center. The Two Step Floating Catchment Area (2SFCA) method was used to measure the potential spatial access to dialysis services. The Kriging algorithm was used for generating self-reported travel time surface in the study area. Finally we performed the Spearman correlation between the potential spatial access and self-reported travel time.Results:Potential spatial access to dialysis center was poor in the northern part of the study area. Fortunately, there were not many hemodialysis patients in that area. There was a significant Spearman association of -0.570 (p<0.01, two-tailed) between the self-reported travel time and computed potential spatial access by 2SFCA method Conclusion:This study contributes that the result of 2SFCA method could be associated with revealed access time to dialysis facilities especially in low traffic and flat areas such as northern Khorasan province of Iran. The map of patients distribution and potential spatial access to the hemodialysis facilities could help policymakers to allocate resources to the unmet areas better.

کلیدواژه ها:

Geographic information system ، 2SFCA ، Kriging ، Access ، Dialysis