This week in the BMJ
Volume 326, Number 7400, Issue of 31 May 2003Research sponsored by drug companies is biased
Research sponsored by drug companies is biased
Outcomes in research that is sponsored by a pharmaceutical company tend to favour the company's product. Lexchin and colleagues (p 1167) reviewed 30 studies that compared research sponsored by the drug industry and research that was funded in other ways. The quality of the methods was at least as good in research sponsored by industry as in research with other sources of funding, but industry sponsored studies were four times as likely to produce favourable outcomes. This might be due, the authors say, to an inappropriate comparator or to publication bias.
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Outpatient treatment for deep vein thrombosis of the leg is safe
Deep vein thrombosis can be treated on an outpatient basis, without any greater risk of complications. Initial treatment with low molecular weight heparins means that activated partial thromboplastin time need not be monitored. Major haemorrhage during initial treatment is less likely, and overall mortality at the end of follow up is reduced, Tovey and Wyatt report (p 1180). These drugs are cost effective, safe, and preferred by patients. Pain or swelling of a lower limb is a relatively common presenting complaint, and the differential diagnosis of deep vein thrombosis is wide. No single investigation is ideal, and often several tests can be performed, either sequentially or in combination.
Drug representatives may increase unnecessary GP prescribing
General practitioners who see drug companies' representatives at least once a week are more likely to express views that lead to unnecessary prescribing. In a questionnaire survey of the attitudes and behaviours of general practitioners throughout England in relation to their prescribing rates, Watkins and colleagues found that practitioners with the greatest contact with drug representatives were most willing to prescribe new drugs and to comply with patients' requests for drugs that are not clinically indicated (p 1178). The doctors who saw drug representatives most frequently tended to be singlehanded practitioners, did not provide postgraduate training, and worked in deprived areas.
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Reporting of clinical trials of drugs shows bias
Results from clinical studies sponsored by the pharmaceutical industry that reach the public domain are subject to bias, according to a study by Melander and colleagues (p 1171). They investigated 42 placebo controlled studies of selective serotonin reuptake inhibitors submitted to the Swedish drug regulatory authority in 1983-99 and compared the published results with the results in the full reports of the studies. A major cause of bias was the tendency to publish only the more favourable per protocol results, rather than intention to treat analyses. Other causes were extensive duplicate publication and a preference for publishing only studies showing significant effects of the drug.
"Opt-out" consent increases uptake of HIV screening
Introducing routine serological testing increases the acceptability and
uptake of HIV screening in genitourinary medicine clinics. Stanley and
colleagues (p 1174) audited
the introduction of routine rather than selective HIV screening in 400
patients and found that uptake was almost doubled. Including HIV in the
package of screening tests did not reduce the uptake of syphilis screening.
These findings supplement those of Read and Winceslaus
(
BMJ
2003;326:
1066-7
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Evidence on stage based approach to smoking cessation is limited
Though services aimed at smoking cessation have made extensive use of the stage based approach, only limited evidence exists for its effectiveness. In a systematic review, Riemsma and colleagues (p 1175) identified 23 randomised controlled trials evaluating a stage based approach for helping people to quit smoking. They found wide variation in the quality of methods and in the theories justifying the interventions used. Few studies reported that the instruments used to assess participants' stage of change had been validated. As a result, the authors say, more rigorous studies are needed before stage based approaches to smoking cessation are considered credible.
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