Copayment policy reforms and effective care utilization by patients with persistent asthma in Taiwan.

Objectives: Reforms to the Taiwan National Health Insurance copayment scheme in 2005 imposed a notable increase in the cost of outpatient visits. This provided an ideal situation to determine whether such reforms lead to a reduction in the utilization of effective care by patients with persistent asthma.

Methods: This study applied the pretest-posttest non-randomized control group design in our analysis of nationwide claims data (2002 to 2010).