Jan 24

Drug company information and physicians’ prescribing

Journal reference: Spurling GK, Mansfield PR, Montgomery BD, et al. Information from pharmaceutical companies and the quality, quantity and cost of physicians’ prescribing: a systematic review. PLoS Med, 2010; 7(10): e1000352 [1]

Link: http://dx.doi.org/10.1371/journal.pmed.1000352

Evidence cookie says...

Exposure to information from pharmaceutical companies does not improve prescribing quality, reduce prescribing frequency or reduce prescribing costs.

General practitioners should avoid pharmaceutical company promotion.

Apart from rare exceptions, the evidence demonstrates either no association between pharmaceutical company promotion and prescribing, or that it:

  • ↓ prescribing quality
  • ↑ prescribing frequency
  • ↑ prescribing costs

Note: there are substantial limitations to the reliability of the evidence base.

More details:


Article details


Study design:

Systematic review of randomised and observational studies, narrative synthesis and meta-analysis


Study aim:

to examine the relationship between exposure to information from pharmaceutical companies and the quality, quantity and cost of physicians’ prescribing


Methods summary:

Following databases searched:

  • Medline
  • International Pharmaceutical Abstracts
  • Embase
  • Current Contents
  • Central

Inclusion criteria:

Outcome measures:

  • Quality, frequency and cost of prescribing

Quality appraisal

  • Studies meeting inclusion criteria were reviewed independently by two authors
  • Methodological quality was formally assessed
  • Studies were only excluded if the two authors found there was insufficient information to appraise their quality.

Results reporting:

  • Narrative synthesis of results (following MOOSE guidelines)
  • Meta-analysis performed on one component:
  • Studies of frequency of prescribing with identifiable control groups where the information exposure was delivered with conventional promotional means

Results summary:

  • 255 articles were retrieved
    • after application of inclusion/exclusion criteria, 58 studies were included in the review
    • cross-sectional studies most common 24/58 (41%)
    • 55% of the studies were conducted in the US
  • Meta-analysis of promotional information and prescribing frequency:
    • There was very significant heterogeneity (I2 = 91%, τ2 = 0.35) so pooled outcome wasn’t provided
    • Sensitivity analysis found that study design, quality factors, year of publication, and type of physician did not explain the heterogeneity
    • Possible causes of the heterogeneity include: passive vs active promotion, variations in the effectiveness of promotion campaigns, promoter’s skills and budget and the target group’s level of resistance to promotion.

Overview:

  • Substantial heterogeneity in reported relationship in the evidence base
  • Prescribing quality:
    • Exposure to information from pharmaceutical companies was associated with either lower prescribing quality or no association detected
    • Only one exception in the included studies.
  • Prescribing frequency:
    • Exposure was associated with either an increase in prescribing frequency or no association detected
    • Three studies found that exposure was associated with increased drug sales up to a point of diminishing returns.
  • Prescribing costs:
    • Exposure was associated with an increase in prescribing costs or no association detected
    • Only one exception in the included studies.

Study conclusion:

With rare exceptions, studies of exposure to information provided directly by pharmaceutical companies have found associations with higher prescribing frequency, higher costs, or lower prescribing quality or have not found significant associations. We did not find evidence of net improvements in prescribing, but the available literature does not exclude the possibility that prescribing may sometimes be improved. Still, we recommend that practitioners follow the precautionary principle and thus avoid exposure to information from pharmaceutical companies.


Participants:

  • Grouped collated data not reported
  • Summary descriptions of the individual studies included reveal that the participants include primary care physicians and physicians frequently, but also paediatric specialists, hospital residents, psychiatrists, ear nose and throat surgeons, chest physicians, gynaecologists as well as prescribers of specific drugs.

Methodological weaknesses

  • Significant limitations of study designs in the included studies
  • Majority of studies were observational; can demonstrate associations but not prove causation or indicate the direction of causality.
  • There may have been significant biases in the included studies.

Methodological strengths

  • Exhaustive extraction and review of available evidence.
  • Results are likely applicable to Australian general practitioners.

Biases and conflicts of interests

  • Lexchin J (fourth author) was paid for work with a Canadian generic company, Apotex Inc., in 2007
  • Spurling GK (primary author), Mansfield PR (second author), Montgomery BD (third author), Lexchin J (fourth author), Othman N (sixth author), and Vitry AI (seventh author); all authors except for one, are members of Healthy Skepticism Inc., an international nonprofit research, education and advocacy association whose aim is “reducing harm from misleading health information”.

Clinical relevance to primary health care

Exposure to information from pharmaceutical companies is ubiquitous in Australian general practice.  Pharmaceutical advertisements are in Australian medical journals, GP news publications, clinical software, and reference texts such as the MIMS formulary.  Most general practices will demonstrate some evidence of pharmaceutical company product placement in the form of office stationary and medication samples.  Pharmaceutical company sponsored education meetings are popularly attended.

There are substantial limitations to the reliability of the evidence used in this systematic review.  However, apart from the rare exceptions, the vast majority of the evidence demonstrates that exposure to pharmaceutical company promotion does not improve in prescribing quality, does not reduce prescribing frequency and does not reduce prescribing costs. Studies have typically found either no association, or that exposure to promotion reduces prescribing quality, increases prescribing frequency and increases prescribing costs.

Expenditure on pharmaceutical promotion directed at physicians is in the tens of billions of dollars worldwide.  There is published evidence to suggest that this is cost-effective for pharmaceutical companies and certainly this assumption has face validity.  General practitioners in primary health care should avoid exposure to information from pharmaceutical companies.

References

  1. Spurling GK, Mansfield PR, Montgomery BD, et al. Information from pharmaceutical companies and the quality, quantity and cost of physicians’ prescribing: a systematic review. PLoS Med, 2010; 7(10): e1000352
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