Comparison of Number and Geographic Distribution of Pediatric Subspecialists and Patient Proximity to Specialized Care in the US Between 2003 and 2019.

Importance: Geographic proximity to a pediatric subspecialist is a key factor in obtaining specialized care. However, comparative data regarding the number of pediatric subspecialists, distribution of subspecialists, and patient proximity to subspecialists in the United States between 2003 and 2019 have not been explored; the last known national analysis was published in 2006 and used data from 2003. Objective: To compare the number and distribution of pediatric subspecialists and patient proximity to pediatric subspecialists in the United States between 2003 and 2019 and to assess whether the increase in the number of pediatric subspecialists is associated with improvements in patient proximity to specialized care and the geographic distribution of pediatric subspecialists. Design, Setting, and Participants: This national repeated cross-sectional study used data from the American Board of Pediatrics to examine the overall change in the number of subspecialists for 20 pediatric subspecialties between 2003 and 2019. The study included 24 375 pediatric subspecialists who were 70 years or younger, had active certification from the American Board of Pediatrics as of June 2019, and had addresses in the United States. Subspecialists' addresses were linked by zip code to child population data to evaluate the geographic distribution of subspecialists, the population-weighted averages for service areas, and the straight-line distances to subspecialists. Descriptive statistics and maps were used to examine patient proximity to subspecialists and regional subspecialist distribution and dispersion by hospital referral region. Subspecialist-to-child population ratios per 100 000 children, changes over time, and coefficients of variation were calculated to further elucidate subspecialist distribution. Data were collected in June 2019 and analyzed from July 8, 2019, to December 17, 2019. Main Outcomes and Measures: Values from 2019 were compared with data from 2003 for mean straight-line distance in miles from patients to subspecialists, by subspecialty; percentage of children younger than 18 years living at specific distance ranges; subspecialist-to-child population ratios across hospital referral regions; and coefficients of variation for population ratios. Results: Among 24 375 pediatric subspecialists 70 years and younger, 23 436 subspecialists were certified in 1 subspecialty, and 939 subspecialists were certified in more than 1 subspecialty. The number of certified pediatric subspecialists in the United States increased by 76.8% between 2003 and 2019, with increases varying across subspecialties. The estimated means for travel distances decreased among all subspecialties; however, depending on the subspecialty, an estimated 1 million to 39 million children (2%-53%) resided 80 miles or more from a subspecialist. An analysis across hospital referral regions indicated increased subspecialist-to-child ratios and an increased number of regions with a subspecialist but continued wide variation across regions for most subspecialties. Eleven subspecialties had 1 or fewer subspecialists per 100 000 children across hospital referral regions. Conclusions and Relevance: Although patient proximity to pediatric subspecialty care has improved nationally, substantial distribution gaps among specific subspecialties remain. Long-term solutions that encourage movement of subspecialists to underserved locations or that extend the practice of current subspecialties may warrant consideration, particularly among subspecialties with a limited number of practitioners.