Increased health costs from mandated Therapeutic Substitution of proton pump inhibitors in British Columbia.

BACKGROUND In 2003, British Columbia's PharmaCare programme implemented a drug reimbursement policy called Therapeutic Substitution, which required patients with acid-related diseases, primarily gastro-oesophageal reflux disease (GERD), to make a medically unnecessary switch from their prescribed proton pump inhibitor (PPI) to the cheapest available brand name PPI (Pariet, rabeprazole sodium), comprising a different (nongeneric) chemical. AIM To evaluate the independent effects of PPI Therapeutic Substitution on individual healthcare utilization among those complying with the policy. METHODS We used the BC Ministry of Health Services' individual-level linked data, allowing isolation of healthcare utilization for the entire population of PPI consumers from 2002 to 2005. RESULTS After controlling for individual case variation in age, gender and a proxy for pre-existing health status, regression analysis revealed statistically significant greater overall use of PPIs, physician services and hospital services independently associated with patients who complied with Therapeutic Substitution. Over the 3-year period 2003-2005, this represented net healthcare expenditures totalling approximately C$43.51 million (C$9.11 million in total PPI drug expenditures, C$24.65 million for physician services and C$9.75 million for hospital services). CONCLUSION Medically unnecessary drug switching caused by compliance with Therapeutic Substitution policy appears to be independently associated with higher overall healthcare utilization.