Pediatric Medical Subspecialist Use in Outpatient Settings.

Importance: A first step toward understanding whether pediatric medical subspecialists are meeting the needs of the nation's children is describing rates of use and trends over time. Objectives: To quantify rates of outpatient pediatric medical subspecialty use. Design, Setting, and Participants: This repeated cross-sectional study of annual subspecialist use examined 3 complementary data sources: electronic health records from PEDSnet (8 large academic medical centers [January 1, 2010, to December 31, 2021]); administrative data from the Healthcare Integrated Research Database (HIRD) (14 commercial health plans [January 1, 2011, to December 31, 2021]); and administrative data from the Transformed Medicaid Statistical Information System (T-MSIS) (44 state Medicaid programs [January 1, 2016, to December 31, 2019]). Annual denominators included 493 628 to 858 551 patients younger than 21 years with a general pediatric visit in PEDSnet; 5 million beneficiaries younger than 21 years enrolled for at least 6 months in HIRD; and 35 million Medicaid or Children's Health Insurance Program beneficiaries younger than 19 years enrolled for any amount of time in T-MSIS. Exposure: Calendar year and type of medical subspecialty. Main Outcomes and Measures: Annual number of children with at least 1 completed visit to any pediatric medical subspecialist in an outpatient setting per population. Use rates excluded visits in emergency department or inpatient settings. Results: Among the study population, the proportion of girls was 51.0% for PEDSnet, 51.1% for HIRD, and 49.3% for T-MSIS; the proportion of boys was 49.0% for PEDSnet, 48.9% for HIRD, and 50.7% for T-MSIS. The proportion of visits among children younger than 5 years was 37.4% for PEDSnet, 20.9% for HIRD, and 26.2% for T-MSIS; most patients were non-Hispanic Black (29.7% for PEDSnet and 26.1% for T-MSIS) or non-Hispanic White (44.9% for PEDSnet and 43.2% for T-MSIS). Annual rates for PEDSnet ranged from 18.0% to 21.3%, which were higher than rates for HIRD (range, 7.9%-10.4%) and T-MSIS (range, 7.6%-8.6%). Subspecialist use increased in the HIRD commercial health plans (annual relative increase of 2.4% [95% CI, 1.6%-3.1%]), but rates were essentially flat in the other data sources (PEDSnet, -0.2% [95% CI, -1.1% to 0.7%]; T-MSIS, -0.7% [95% CI, -6.5% to 5.5%]). The flat PEDSnet growth reflects a balance between annual use increases among those with commercial insurance (1.2% [95% CI, 0.3%-2.1%]) and decreases in use among those with Medicaid (-0.9% [95% CI, -1.6% to -0.2%]). Conclusions and Relevance: The findings of this cross-sectional study suggest that among children, 8.6% of Medicaid beneficiaries, 10.4% of those with commercial insurance, and 21.3% of those whose primary care is received in academic health systems use pediatric medical subspecialty care each year. There was a small increase in rates of subspecialty use among children with commercial but not Medicaid insurance. These data may help launch innovations in the primary-specialty care interface.