Supply of obstetrician-gynecologists and gynecologic oncologists to the US Medicare population: a state-by-state analysis.

Background: The supply of obstetrician-gynecologists and gynecologic oncologists across the United States has been described. However, these studies focused on reproductive-age patients and did not assess the growing demand for services to the advanced-age female population.

Objective: This study aimed to evaluate the supply of obstetrician-gynecologists and gynecologic oncologists who serve the US Medicare population per 100,000 female Medicare beneficiaries, over time and by state and region.

Study Design: The supply of obstetrician-gynecologists and gynecologic oncologists was extracted from the Physician and Other Supplier Public Use File database of Medicare Part B claims submitted to the US Centers for Medicare & Medicaid Services. Data were only available from 2012 to 2019. The supply of providers was divided by the number of original female Medicare beneficiaries obtained from the Kaiser Family Foundation; all values reported are providers per 100,000 female beneficiaries by state. Trends over time were assessed as the difference in provider-to-beneficiary ratio and the percentage change from 2012 to 2019. All data were collected in 2021. All analyses were performed with SAS, version 9.4. This study was exempt from institutional review board approval.

Results: In 2019, the average number of obstetrician-gynecologists per 100,000 female beneficiaries across all states was 121.32 (standard deviation±33.03). The 3 states with the highest obstetrician-gynecologist-to-beneficiary ratio were the District of Columbia (268.85), Connecticut (204.62), and Minnesota (171.60), and the 3 states with the lowest were Montana (78.37), West Virginia (82.28), and Iowa (83.92). The average number of gynecologic oncologists was 4.48 (standard deviation±2.08). The 3 states with the highest gynecologic oncologist-to-beneficiary ratio were the District of Columbia (11.30), Rhode Island (10.58), and Connecticut (9.24), and the 3 states with the lowest were Kansas (0.82), Vermont (1.41), and Mississippi (1.47). The number of obstetrician-gynecologists per 100,000 female beneficiaries decreased nationally by 8.4% from 2012 to 2019; the difference in provider-to-beneficiary ratio from 2012 to 2019 ranged from +29.97 (CT) to -82.62 (AK). Regionally, the Northeast had the smallest decrease in the number of obstetrician-gynecologists per 100,000 female beneficiaries (-3.8%) and the West had the largest (-18.2%). The number of gynecologic oncologists per 100,000 female beneficiaries increased by 7.0% nationally during the study period; this difference ranged from +8.96 (DC) to -3.39 (SD). Overall, the West had the smallest increase (4.7%) and the Midwest had the largest (15.4%).

Conclusion: There is wide geographic variation in the supply and growth rate of obstetrician-gynecologists and gynecologic oncologists for the female Medicare population. This analysis provides insight into areas of the country where the supply of obstetrician-gynecologists and gynecologic oncologists may not meet current and future demand. The national decrease in the number of obstetrician-gynecologists is alarming, especially because population projections estimate that the proportion of elderly female patients will grow. Future work is needed to determine why fewer providers are available to see Medicare patients and what minimum provider-to-enrollee ratios are needed for gynecologic and cancer care. Once such ratios are established, our results can help determine whether specific states and regions are meeting demand. Additional research is needed to assess the effect of the COVID-19 pandemic on the supply of women's health providers.