The Impact of DCA on the Use and Effectiveness of Statin Drugs
- Presenter:
Chair: Ernst R. Berndt; Discussant: Mon June 5, 2006 17:15-18:45 Room 335
In August of 1997 the Food and Drug Administration (FDA) relaxed the rules governing television direct to consumer advertising (DCA) of prescription pharmaceutical products. Little is currently known about the effects of DCA for the efficient allocation of prescription drugs. In this study, we will examine how DCA affects physician prescribing patterns, courses of care, and health outcomes for patients suffering from high cholesterol (hyperlipidemia). Currently, Congress and the Food and Drug Administration are investigating whether the 1997 regulatory relaxation should be reversed. In the face of this pressure, the pharmaceutical industry has voluntarily agreed to abstain from advertising a new drug within the first six months of its release. In addition, the recent expansion of Medicare to include a prescription drug benefit has enhanced the potential of DCA to impact Federal budgets. Thus, this research, by investigating whether DCA does or does not have a pernicious effect on the efficiency of health care delivery in primary care settings, will be of high policy relevance.
The primary data for this study are taken from a geographically diverse national research network of primary care practices. As of 2004, 81 practices in 32 states, with 348 physicians, are or have been network members. Currently, the entire research network database has clinical chart and demographic information on 604,111 patients, including 3.8 million prescription records. We extract a sub-set of 51,853 patients who have a diagnosis of hyperlipidemia (for years 1998 – 2004). Advertising data is collected at the level metropolitan areas, for the top 75 media markets. Brand specific advertising data is collected at the monthly-level for: local television, network television, national magazine and newspaper and local magazine and newspaper.
The first part of the paper seeks to determine the degree to which DCA affects physician patient populations. We estimate the effect of aggregate and brand-specific advertisement on the number of hyperlipidemia-related visits at the physician practice level. Estimating the effect of DCA on patient populations is a necessary first step in controlling sample selection in the patient level analysis.
We then estimate the impact of DCA on a disaggregated (patient level) population. DCA may have contradictory effects on patients: it may improve efficiency of care by encouraging patients to accept and adhere to effective treatments; on the other hand, DCA may reduce the efficiency of care by attracting patients who have only marginally severe conditions, and whose health state does not therefore have much room for improvement. To assess this, we estimate the effect of DCA on the joint the likelihood that the patient is prescribed one of the study drugs (Zocor, Pracachol or Lipitor) and the likelihood that their cholesterol levels are brought to within guidelines.
