Investigators of a study that looked at how conflict-of-interest policies affect medication prescribing found that physicians in academic medical centers (AMCs) prescribed fewer promoted drugs and more non-promoted drugs in the same drug classes following policy changes to restrict marketing activities at those institutions.
Ian Larkin, PhD, assistant professor of strategy at the University of California, Los Angeles School of Management, and George Loewenstein, PhD, Herbert A. Simon Professor of Economics and Psychology at Carnegie Mellon University in Pittsburgh, led a team of researchers that looked at prescribing by physicians affiliated with 19 academic medical centers in five states between January 2006 and June 2012.
During the study period, these centers instituted policies limiting pharmaceutical sales representative detailing. The study compared prescribing by 2,126 physicians affiliated with these centers with that of 24,593 physicians with similar backgrounds and prescribing habits selected from a database of physicians in the same states provided by a large pharmacy benefits manager. The analysis in this study encompassed eight major drug classes: lipid-lowering drugs, gastroesophageal reflux disease drugs, antidiabetic agents, antihypertensive drugs, sleep aids, attention deficit hyperactivity disorder drugs, antidepressant drugs, and antipsychotic drugs.
The authors reported changes in prescribing in terms of variations in the market share of detailed and nondetailed drugs. The mean market share of detailed drugs (across all drug classes) in AMCs prior to changes in policy was 19.3%. Over the period of the study, the market share of detailed drugs prescribed by AMC physicians declined by 1.7 percentage points, an 8.7% decrease relative to the level prior to policy changes. The market share of prescribed nondetailed drugs increased 0.84 percentage point, or a relative 5.6% increase.
The decline in prescriptions of detailed drugs was greatest at centers with the most stringent policies, such as bans on salespeople in patient care areas, requirements for salesperson registration and training, and penalties for salespeople and physicians who violated the policies.
Additional analysis showed that the changes in prescribing were evident whether or not detailed drugs for which a generic version became available during the study were included in the data. Also, because AMCs instituted policy changes at different times during the study period, the authors compared prescribing during equivalent stretches of time (up to three years) immediately before and after each center’s policy had changed.