Jonathan Tan’s lab presents at the 2024 IMGS
On Monday, July 15, 2024, SSI researcher Alicia Adiwidjaja presented at the 2024 International Medical Geography Symposium (IMGS). This biannual meeting brings together health and medical geographers from around the world, who met this year at Georgia State University in downtown Atlanta, Georgia. Adiwidjaja made the presentation “Distance to Care: Measuring Temporal Variability in Pediatric Health System Access” on behalf of her fellow researcher Andrew Kampfschulte, M.S., a Ph.D. candidate in the USC Population, Health and Place doctoral program, and the research team leader Dr. Jonathan Tan. Tan is an assistant professor of clinical anesthesiology and spatial sciences of the University of Southern California.
Transportation Burden
The research focused on transportation burden experienced by patients of Children’s Hospital Los Angeles (CHLA) by measuring driving accessibility to the hospital using electronic health record data. CHLA is the largest freestanding pediatric health system of the west coast of the United States. It serves a diverse population of children across race, ethnicity, socioeconomic status, geography and environments.
Adiwidjaja explained, “We worked as a team to obtain electronic health record data for children cared for across CHLA and geocoded each patient. Andrew was instrumental in creating a driving route to the hospital from each patient address. From there, drive times were calculated for each patient throughout the course of the day. This allowed for a deeper look into how drive-time can vary across geography and time of day. For example, a patient might be a 20-minute drive away from CHLA at 6 am but then a 50-minute drive away from CHLA at 9 am. This change in drive-time was derived for each patient then mapped to check for spatial patterns. We found that variation in drive-time accessibility to CHLA was not spatially random.”
Kampfschulte’s methodology compares traditional different methods of measuring “access” from centroid measurements to Euclidian distance measurements. In comparison to the routing distance method used in this study, he found that centroid measures of distance at both the ZCTA-level and tract-level underestimated true distances from patient addresses to the hospital. He observed this underestimation to be inconsistent across the board.
In his analysis, Kampfschulte notes that Euclidian distance measures weren’t any better at estimating true distances. For example, a traditional method might have estimated that a patient was only 30 miles away from the hospital. However, the routing distance shows that the true distance is actually closer to 50 miles. He also found that these traditional methods of measuring access are prone to error for all population groups and some more than others. And so, variation in driving distance to CHLA based on traditional methodology is also not spatially random.
Addressing health care disparities
“To ensure patients can get the care they need on time, we need to figure out if patients can get to the hospital on time,” said Adiwidjaja. She stressed the importance of data-informed policy making for health system leaders: “This research will help optimize scheduling practices to create more equitable interventions for health systems like CHLA.”
Adiwidjaja concluded by noting that it takes a multidisciplinary team from CHLA and the USC Spatial Sciences Institute to study and address disparities in pediatric healthcare.
Dr. Tan has received research grant funding from the Anesthesia Patient Safety Foundation, Foundation for Anesthesia Education and Research, and the Southern California Environmental Health Sciences Center. Andrew Kampfschulte has received pre-doctoral award research funding from The Saban Research Institute at CHLA. Alicia Adiwidjaja received her B.S. in Geodesign, a program of the Spatial Sciences Institute at the University of Southern California.