The concealment came to light only in the past few weeks after researchers looked back at the original data that was being prepared in the 1990s. They discovered that between just 3 to 33 per cent of adverse reactions were being published, and one study alone recorded 1,318 adverse reactions that were kept secret.
Another discovered that people taking orlistat were suffering twice as many reactions as others who were given a placebo, or sugar pill; again, the discovery never made it into any published papers.
Despite the concealment, six of the seven papers re-examined had stated that “all adverse reactions were recorded,” researchers from the Nordic Cochrane Centre in Copenhagen have discovered. Gastro-intestinal reactions were the most common problems, but researchers recorded them only if the participant described their reactions as ‘bothersome’.
The Cochrane researchers were able to get hold of the data as part of a Freedom of Information request. The data had been gathered from seven randomised, placebo-controlled trials, which had involved a total of 4,225 obese participants.