Effects of delisting nonprescription combination drugs on health insurance expenditures for pharmaceuticals in Korea.

In November 2006, 727 combination drugs in 24 therapeutic classes were delisted in the national formulary in Korea to reduce the country's pharmaceutical expenditure, making these 727 drugs non-reimbursable. This study examines the effects of this delisting on national health insurance expenditures for pharmaceuticals. An interrupted time series analysis was conducted for the period from January 2005 to August 2007 by using administrative claims from Korea's National Health Insurance. The main outcome variable was the total pharmaceutical expenditure measured as a whole and based on the level of health care institutions and therapeutic classes. Comparison between exposure group (delisted drugs) and non-exposure group (listed drugs) were done. No changes in the level of or trend in the total pharmaceutical expenditure were detected. However, the delisting reduced pharmaceutical expenditures in clinics. Delisting effects were also observed according to therapeutic classes of drugs. The results indicate that any delisting should take into account the type of drug.