From clinical trials to real-world practice: Use of atypical antipsychoticmedication nationally in the Department of Veterans Affairs

BACKGROUND. Although clinical trials evaluate pharmacotherapeutic intervent ions under highly controlled conditions, there remains a need to evaluate m edication use in actual practice. METHODS. Patients prescribed atypical antipsychotic medications in the VA s ystem during a 4-month period in 1999 (n = 73,981) were classified into 32 groups on the basis of clinical diagnosis and recent level of inpatient use . Variation was examined across groups in drug costs, agents, dosages, and duration of use. The potential impact of these medications on VA costs was estimated by calculating medication costs and subtracting estimated inpatie nt savings. RESULTS. A majority of patients were diagnosed with schizophrenia (57.2%), but substantial off-label use of these medications to treat other psychiatr ic illnesses was also evident (42.8%). Compared with published trials repor ting average annual costs from $3,000 to $7,000, average annualized pharmac y costs were only $1,395 per patient because of a 58.5% VA price discount; relatively low dosing, especially for people with diagnoses other than schi zophrenia; and medication prescription coverage for only 75% of the days in the study period. The sample averaged only 6.96 inpatient days; as a resul t, potential inpatient savings were limited. Assuming 0% to 18% inpatient s avings, annual net drug costs are estimated to range from $500 to $1,152 pe r patient. CONCLUSIONS. Medication costs in actual practice can be substantially lower than in clinical trials. Atypical antipsychotic medications in actual VA p ractice incur net costs estimated at $500 to $1,152 per patient per year wi th substantial variation across clinical subgroups.