Trends in payments among male and female ophthalmologists in Ontario from 1992 to 2018

Objective: To examine sex differences in Ontario Health Insurance Plan (OHIP) payments from 1992 to 2018. Design: Population-based observational study. Participants: Ophthalmologists submitting claims to OHIP from 1992 to 2018. Methods: Physician billing data over 27 years (1992-2018) were analyzed for yearly number of ophthalmologists, OHIP payments, distinct patients, and patient visits. Results: Yearly median OHIP payments to female ophthalmologists were less than to male ophthalmologists with a gap ratio of 0.55 in 1992 to 0.73 in 2018. Stratifying by full-time equivalent (FTE), there was little difference in median payments between males and females for 1 FTE. Median female-to-male payments ratio varied from 0.80 to 1.16 for <1 FTE and 1.14 to 0.84 for >1 FTE from 1992 to 2018. Among female ophthalmologists, 72.7% and 52.9% were <1 FTE and 11.4% and 19.2% were >1 FTE in 1992 and 2018, respectively. In comparison, for male ophthalmologists, 35.7% and 45.6% were <1 FTE and 43.4% and 45.6% were >1 FTE in 1992 and 2018, respectively. Overall, male ophthalmologists had more patients and patient visits than female ophthalmologists, but there was little difference between male and female ophthalmologists for 1 and >1 FTE. The results for <1 FTE varied by year. Conclusions: Overall, female ophthalmologists have lower OHIP payments compared with males, but there was little difference for those stratified to 1 FTE. This overall payments difference by sex is largely explained by the higher proportion of <1 FTE females, lower proportion of >1 FTE females, and higher payments for >1 FTE males.