Healthy Skepticism Library item: 2004

Warning: This library includes all items relevant to health product marketing that we are aware of regardless of quality. Often we do not agree with all or part of the contents.

Publication type: news

Wysong P.
Time with drug reps affects prescribing: study
The Medical Post. 2002 Sep 8

Full text:

Doctors, who spend more time with drug reps are more likely to prescribe more costly drugs

CHICAGO – The more time doctors spend with drug representatives, the more likely they are to prescribe the newer, more expensive drugs. Yet doctors seem to believe their prescribing habits are not influenced by drug company representatives. These are two findings from study looking at the amount of time doctors spend with drug company reps, what they believe their prescribing practises are, and what they actually prescribe. The study was presented by Dr. Roxann Powers, professor of medicine at West Virginia University (WVU) school of medicine, Morgantown, at the annual meeting of the Society of General Internal Medicine.

The study was done in two parts:

First, all faculty and resident physicians in family practice (FP) and general internal medicine (GIM) at WVU were surveyed about the amount of time they spend with drug reps, what their preferred sources of information about drugs were, and what they believed to be their practise style when it came to prescribing drugs for heart disease. Researchers compared FPs to GIM doctors because it was already known that “there was significant difference in interaction with pharmaceutical representatives between the two groups,” said Dr. Powers. “Family (doctors) at our institution have pharmaceutical reps around all the time in their practice. They bring in samples, provide lunches, those sorts of things.” In fact, the FP clinic “has a whole room full of samples, whereas in our clinic in internal medicine we just have a cabinet.’ A total of 31 FPs and 47 GIM doctors participated.

In a second part of the study, computerized medication lists of hypertensive patients were reviewed to determine actual prescribing practices.

When asked how often they received information from drug reps, 84% of the FPs said More than once a week. Of the GIM doctors, only 14% said they received information more than once a week.

When asked what their main source of information about antihypertensives was, 23% of FPs and 9% of GIMs said pharmaceutical reps.

A significant portion of both groups also said they relied on journal articles – 61% of FPs and 49% of GIMs.

“Many participants selected more than one source in the questionnaire,” Dr. Powers said. When asked what they usually did when selecting an antihypertensive, 77% of FPs and 81% of GIMs said they relied on medication shown to reduce cardiovascular risk. Of the FPs, 35% said they selected from samples, but only 11% of GIMs did this.

GIMs were more likely to use less expensive drugs, with 34% saying they used this as a selection criterion, compared with 29% of FPs. An analysis of the computerized medical records showed there were other differences between FPs and GIMs. FPs were more likely to prescribe ACE inhibitors and calcium channel blockers. Out of 2,199 prescriptions written for these drugs, 53% were from FPs and 46% from GIM. Of 1,890 prescriptions for beta-blockers and diuretics, 39% were from the FPs and 47% from GIM doctors.

Prescriptions for patients with diabetes, asthma, chronic obstructive pulmonary disease, or other diseases in which beta-blockers or diuretics were contraindicated were excluded from the analysis.

“What it showed was the FPs, who interact with pharmaceutical representatives more than once a week, 80% of the time, are statistically more likely to use the more expensive ACE inhibitors and calcium channel blockers. These are what the drug representatives would be promoting,” Dr Powers said.

The drug reps rarely bring beta-blockers or diuretics to a doctor’s practice, she said.

When doctors have a lot of samples, they are probably more likely to give them to patients. Once a patient is started on a sample drug, a doctor may likely opt for continuity and write prescriptions for those drugs later, she said. “We should all know that we may not be getting the best information from pharmaceutical reps. We get our best information from randomized controlled trials.” Dr Powers said.

In a survey of 31 family physicians (FP) and 47 general internal medicine (GIM) doctors, the FPs much more regularly got information from drug company reps than GIM doctors. Here is what the doctors described as their main source of information about antihypertensive therapy (some doctors picked several sources):

Main source of information Family doctors General Internal Medicine doctors
Journal articles 61% 49%
Lectures 51% 49%
1993 Fifth Joint National Committee 23% 38%
Colleagues 42% 34%
Drug reps 23% 9%

Here is the treatment choice for the same doctors asked to prescribe for an initial choice of therapy for a 44 year old with newly-diagnosed essential hypertension unresponsive to non-pharmacologic interventions (some doctors picked both treatments):