Diffusion of new medication across different income groups under a universal health insurance program: an example involving newly enlisted nonsteroidal anti-inflammatory drugs for elderly osteoarthritis patients.

OBJECTIVES: The aim of this research was to determine whether socioeconomic status, as measured by income level, impacts on the diffusion to patients of newly reimbursed nonsteroidal anti-inflammatory drugs (NSAIDs) under the National Health Insurance program in Taiwan.
METHODS: We used income tax records to identify the income levels of 324 male and 551 female randomly sampled osteoarthritis patients aged over 60 years in 2000. The study period was 2 years (t (1) = April 2001-March 2002 and t (2) = April 2002-March 2003). Generalized estimating equation models were used to analyze the impact of income level on being prescribed one of the newly reimbursed NSAIDs.
RESULTS: The impact of income level on being treated with the new drug was positive and significant for females (OR = 2.11, p < 0.01) but not for males. The interaction term between income groups and the time trend was insignificant. Other factors associated with being treated with the new drug include age, habit of health-care utilization, and residential characteristics.
CONCLUSIONS: Diffusion of new drugs still depends on income level despite the presence of a universal national health insurance system in Taiwan.