The impact of OHIP+ pharmacare on use and costs of public drug plans among children and youth in Ontario: a time-series analysis

BACKGROUND: In 2018, Ontario implemented a pharmacare program (Ontario Health Insurance Plan Plus [OHIP+]) to provide children and youth younger than 25 years with full coverage for prescription medications in the provincial formulary. We aimed to assess the use of public drug plans and costs of publicly covered prescriptions before and after the program's implementation and modification. METHODS: We conducted a population-based, interrupted time-series analysis using data on prescription drug claims, from the Canadian Institute for Health Information's National Prescription Drug Utilization Information System, for people younger than 25 years from January 2016 to October 2019 in Ontario, using British Columbia as the control. We assessed changes in the level and trend of publicly covered prescriptions and expenditures after the introduction of OHIP+ in January 2018 and after program modifications in April 2019. We also assessed plan use and expenditures for publicly covered prescriptions for diabetes and asthma. RESULTS: Publicly covered prescriptions in Ontario increased by 290%, from 756 per 1000 people before OHIP+ to 2952 per 1000 (p < 0.001) after its implementation. After program modification, prescriptions decreased by 52% to 1421 per 1000 (p < 0.001). Similarly, total public drug expenditures increased by 254%, from $379 million in 2017 to $839 million in 2018, then reduced by 49% to $204 million in 2019. Monthly public plan expenditures increased by $115.94 (95% confidence interval [CI] $100.93 to $130.94) post-OHIP+ implementation and decreased by $99.97 (95% CI -$119.79 to -$80.15) per person per month after April 2019. INTERPRETATION: Adopting OHIP+ increased use of public drug plans and expenditures for publicly funded prescription medicines, and the program modification was associated with decreases in both outcomes. This study's findings can inform the national pharmacare debate; future research should investigate associations with health outcomes.