“Evidence” and marketing

If you prescribe drugs, the pharmaceutical industry is interested in you and is investing a staggering sum of money trying to influence you. The most effective way of changing the prescribing habits of a clinician is through personal representatives (known in Britain as “drug reps” and in North America as “detailers”), who travel round with a briefcase full of “evidence” in support of their wares.1

Pharmaceutical “reps” do not tell nearly as many lies as they used to (drug marketing has become an altogether more sophisticated science), but they have been known to cultivate a shocking ignorance of basic epidemiology and clinical trial design when it suits them.2 It often helps their case, for example, to present the results of uncontrolled trials and express them in terms of before and after differences in a particular outcome measure.3 The recent correspondence in the Lancet and BMJ on placebo effects should remind you why uncontrolled before and after studies are the stuff of teenage magazines, not hard science.4 5 6 7 8 9 10 11 12

Making decisions about treatment

Sackett and colleagues have argued that before giving a drug to a patient the doctor should:

• identify, for this patient, the ultimate objective of treatment (cure, prevention of recurrence, limitation of functional …