Reassessing Definitions of Patient Populations

TOPLINE:

Patient travel patterns often differ from geographic market boundaries, particularly for specialty care. The researchers sought to assess how well thresholds such as hospital service area (HSA) or zipcode capture the true travel time to access to care for a majority of patients. Primary care service area (PCSA) and HSA were not accurate definitions of a patient population.

METHODOLOGY:

• Researchers used data of healthcare utilization from Medical Expenditure Panel Survey (MEPS), from 2018 to 2021.
• A total of 825,292 office visits, 23,334 emergency department visits, and 10,552 inpatient stays were analyzed.
• Researchers used an online geographic information system to geocode patient and provider addresses. Travel times were calculated using a routing engine and OpenStreetMap data.
• They also determined if visits fell within various boundaries such as HSA or county.

TAKEAWAY:

• For emergency department visits, 74.8% occurred within the patient’s county, with 81.3% located within 30 minutes of their home and 92.4% within 60 minutes of home.
• A smaller percentage of inpatient stays fell within these boundaries, with 63.3% in the patient’s county and 86.4% within 60 minutes of their home.
• Zipcodes overall covered the least amount of patients; for instance, 21.6% of all office visits were of patients who lived within the zipcode of the health provider, while 53.8% of encounters were of patients who traveled less than 15 minutes to their appointment.
• 86.4% of inpatient hospital stays were composed of those driving 60 minutes or less, closely mirroring the hospital referral region (HRR) definition of 85.4 minutes.

IN PRACTICE:

“We find that some geographic market definitions (such as HSA and PCSA) exclude much of the care utilized by residents. Using these boundaries may result in underestimation of access to care or competition,” the study authors wrote. “Larger units (for example, 60-minute travel time and HRR) capture most visits but exceed typical travel distances. Thus, research using large geographic units may overestimate access or competition.”

SOURCE:

The study was led by Sandra L. Decker, PhD, of the Agency for Healthcare Research and Quality in Rockville, Maryland. It was published online on November 5 in the Annals of Internal Medicine.

LIMITATIONS:

Study limitations included potential underreporting of medical encounters in the MEPS, as well as potential errors in provider location reporting. Travel time results assume transportation by car. Definitions of geographic markets, like HSAs and PCSAs, excluded much of the care used by residents.

DISCLOSURES:

No disclosures were reported.

This article was created using several editorial tools, including AI, as part of the process. Human editors reviewed this content before publication.