Health care provider knowledge of drug formulary status in ambulatory care settings.

PURPOSE: Health care providers' knowledge of whether the medications they prescribed were on the formulary of their patients' insurance plan and factors associated with this knowledge were examined.
METHOD: The 2000 National Ambulatory Medical Care Survey was used to construct a nationally representative sample of outpatient prescription drugs and determine providers' knowledge of the formulary status of the drugs they prescribed. In addition to univariate analysis, random-effects logistic regression models were conducted to examine the association between providers' knowledge of whether a patient's medication was on the formulary, payment types, and provider and medication characteristics.
RESULTS: Providers did not know whether the drug they prescribed was on the formulary for over 64% of the prescriptions. Physicians were more likely to know whether HMO patients' medications were on the formulary. Internal medicine physicians were significantly less likely to know if their patients' medications were on the formulary than general and family practice physicians. Among HMO-paid outpatient visits, providers practicing in the West were significantly less likely to know if their patients' medications were on the formulary than those practicing in the Northeast.
CONCLUSION: In over half of cases, health care providers did not know whether the medications they prescribed were on the formulary.