Impact of income-based deductibles on drug use and health care utilization among older adults.

backgroundIncome-based deductibles are present in several provincial public drug plans in Canada and have been the subject of extensive debate. We studied the impact of such deductibles in British Columbia's Fair PharmaCare plan on drug and health care utilization among older adults.

methodsWe used a quasi-experimental regression discontinuity design to compare the impact of deductibles in BC's PharmaCare plan between older community-dwelling adults registered for the plan who were born in 1928 through 1939 (no deductible) and those born in 1940 through 1951 (deductible equivalent to 2% of household income). We used 1.2 million person-years of data between 2003 and 2015 to study public drug plan expenditures, overall drug use, and physician and hospital resource utilization in these 2 groups.

resultsThe income-based deductible led to a 28.6% decrease in person-years in which public drug plan benefits were received (95% confidence interval [CI] -29.7% to -27.5%) and to a reduction in the per capita extent of annual benefits by $205.59 (95% CI -$247.81 to -$163.37). Despite this difference in public subsidy, we found no difference in the number of drugs received or in total drug spending once privately paid amounts were accounted for (

interpretationA modest income-based deductible had a considerable impact on the extent of public subsidy for prescription drugs. However, it had only a trivial impact on overall access to medicines and use of other health services. Unlike copayments, modest income-based deductibles may safely reduce public spending on drugs for some population groups.