title: Are we there yet? Distance to care and relative supply among pediatric medical subspecialties.
abstract: OBJECTIVE
  The objective of this study was to describe geographic proximity, quantify variation in supply, and estimate pediatric population increments that are needed to support providers across pediatric subspecialties.
  
  
  METHODS
  Data from the American Board of Pediatrics and the Claritas Pop-Facts Database were used to calculate subspecialty-specific straight-line distances between each zip code and the nearest board-certified subspecialist. These data sources also were used to estimate the percentage of hospital referral regions with providers and calculate physician-to-population ratios for each of 16 pediatric medical subspecialties. Coefficients of variation for the ratios were used to assess intraspecialty variation in supply across markets. Estimates of the pediatric population that is needed to support an initial or additional physician in a market were generated using subspecialty-specific ordered logit analyses.
  
  
  RESULTS
  The population-weighted average distance to a subspecialist ranged from 15 miles for neonatology to 78 miles for pediatric sports medicine. For most pediatric subspecialties, more than two thirds of children live within 40 miles of a certified physician. For 7 of 16 of pediatric subspecialties, fewer than one half of hospital referral regions have a provider. Coefficients of variation vary across subspecialties and are lowest for neonatology at 76% and greatest for pediatric sports medicine at 287%. Pediatric population thresholds likewise vary with a tendency toward lower thresholds for procedural specialties, such as cardiology and critical care medicine.
  
  
  CONCLUSIONS
  The practice locations of pediatric subspecialists parallel the geographic distribution of children in the United States, yet many hospital referral regions lack pediatric subspecialists and coefficients of variation vary widely across subspecialties. These findings suggest that either the supply of pediatric subspecialists is inadequate, pediatric subspecialists are distributed inequitably, or the market for pediatric subspecialists is larger than the hospital referral regions. Furthermore, population thresholds for many cognitive pediatric subspecialties are high; the extent to which high thresholds reflect low disease prevalence versus other factors, such as inadequate reimbursement, is not established.
authors.affiliation: Department of Health Policy and Administration, UNC Chapel Hill School of Public Health, Cecil G. Sheps Center for Health Services Research, CB 7590, Chapel Hill NC 27599-7590, USA. michelle_mayer@unc.edu
authors.forename: Michelle L
authors.initials: ML
authors.lastname: Mayer
mesh_terms: D002648:Child; D002662:Child Health Services / Q000600:supply & distribution*; D006297:Health Services Accessibility / Q000706:statistics & numerical data*; D006801:Humans; D010372:Pediatrics / Q000706:statistics & numerical data*; D012017:Referral and Consultation; D014481:United States