Impact of Medicaid copayments on patients with cancer: lessons for Medicaid expansion under health reform.

BACKGROUND: The Medicaid program plays a critical role in providing insurance coverage for many low-income beneficiaries who are diagnosed with cancer. Several states have increased their copayment requirements in the past few years and this provides a natural experiment to study the impact of copayments.
METHODS: We used Medicaid administrative data linked with cancer registry data for the years 1999 to 2004 from Georgia (intervention state with increases in copayments), Texas (control state A), and South Carolina (control state B) to study the impact of copayments on adult (aged from 18 to 64 y) Medicaid beneficiaries diagnosed with cancer (n=10,241). We report both pre/post and difference-in-difference assessments controlling for confounding factors including demographics, comorbidities, cancer site, and stage at diagnosis.
RESULTS: After copayments were imposed, the number of days of supply of prescription drugs in the intervention state decreased by 127.4 and 150.1 days compared with control state A and B, respectively. Those with multiple comorbidities reduced their use of prescription drug the most. The proportion of beneficiaries with emergency room visits also increased in the intervention state compared with the control states. Overall, total 6-month cost was more than $2000 higher per patient in the intervention than the control states.
CONCLUSIONS: The results show that Medicaid patients with cancer when faced with even moderate copayments change their health-seeking behavior. State Medicaid programs should reconsider the use of copayments as they do not decrease overall cost, but instead could potentially result in negative consequences.