Medisinsk kunnskap før og nå: Fra teori til systematiske oversikter

Abstract

The humoral medicine-theory dominated the understanding of diseases and thus also medical treatments over 2,000 years. Purgatives, bloodletting and laxatives were frequently used to correct "imbalances" between body fluids, which were seen as the cause of disease. It was not until the 18th century that actual empirical knowledge was seen as important as a basis for making decisions about choice of treatment. At this time, the idea of counting the outcomes among patients receiving a treatment and compare with patients who did not, was a new approach for presenting treatment effects. As of the 19th century there are many examples of treatments being tested by the use of alternation, i.e. allocating every other patient to the treatment under evaluation. The UK Medical Research Council's streptomycin-trial (1946) is regarded as the first randomised controlled trial in medicine, and for having set the standard for clinical trials. In his book, "Effectiveness and Efficiency. Random Reflections on Health Services" (1972), Archie Cochrane criticised the lack of evidence for many of the interventions being performed in the health services. He called for far more randomised trials. He also proposed that findings from randomised trials should be collated, and that the results should be summarised on a regular basis. Iain Chalmers took the challenge and engaged in the huge task of developing a database of randomised controlled trials. With the database as a starting point, several systematic reviews of current evidence on the effects of interventions in the health services were produced. This was the start of the Cochrane Collaboration.