Promotie van medicijnen voor gezonde mensen?*
Het is de laatste jaren niet de eerste keer dat wetenschappers alarmeren over de promotionele activiteiten van de farmaceutische industrie. Deze waarschuwing betreft het fenomeen disease mongering ofwel nieuwe ziekten uitvinden om medicatie te verkopen. Medicijnen die beoordeeld zijn voor toepassing bij
osteoporose ( een botdensiteit die -2.5x onder de standaarddeviatie ligt) worden nu al gepromoot voor vrouwen met osteopenie (een botdensiteit die tussen -1 en -2.5x onder de standaarddeviatie). Deze vrouwen zouden met een medicijn 75%
minder kans hebben op een botbreuk. Doch zij zeggen niet dat dit absoluut gezien slechts 0,9% vermindering van risico is. Anders gezegd om 1 botbreuk te kunnen voorkomen moeten 270
gezonde vrouwen 3 jaar lang een dergelijk medicijn slikken. Over de bijwerkingen van die medicijnen zoals een duidelijk verhoogde kans op bloedstolsels wordt niet gerept.
Value of drugs for pre-osteoporosis exaggerated
A series of recent scientific publications have exaggerated the benefits and underplayed the harms of drugs to treat pre-osteoporosis or "osteopenia" potentially encouraging treatment in millions of low risk women, warn experts in this week's BMJ.
The authors believe that this represents a classic case of disease-mongering: a risk factor being transformed into a medical disease in order to sell tests and drugs to relatively healthy people.
Osteopenia or "pre-osteoporosis" is said to affect around half of all older women and, in at least one country, drug companies have already begun to market their drugs to women with osteopenia, based on re-analyses of four osteoporosis drug trials.
But the authors of this week's BMJ paper argue that this move raises serious questions about the benefit-risk ratio for low risk individuals, and about the costs of medicalising and potentially treating an enormous group of healthy people.
These reanalyses tend to exaggerate the benefits of drug therapy, they say. For example, the authors of one reanalysis cite a 75% relative risk reduction, though this translates into only a 0.9% reduction in absolute risk.
In other words, up to 270 women with pre-osteoporosis might need to be treated with drugs for three years so that one of them could avoid a single vertebral fracture.
Most of the reanalyses also play down the harms of drug therapy, they add. For example, the reanalysis of data for the drug raloxifene focuses solely on the potential benefits, with no mention of an increased risk of blood clots.
Finally, like much of the published literature on osteoporosis, these analyses have potential conflicts of interest, they write. For instance, all of the original drug trials being re-analysed were funded by industry and, in three out of four cases, drug company employees were part of the team conducting the reanalyses.
The World Health Organisation is currently developing guidance on how to deal with women categorised as having osteopenia. Whether this will stop industry efforts to encourage treatment in low risk women is, however, questionable, they say.
"We need to ask whether the coming wave of marketing targeting those women with pre-osteoporosis will result in the sound effective prevention of fractures or the unnecessary and wasteful treatment of millions more healthy women," they conclude.
http://www.bma.org.uk/ (Februari
2008)
Reacties:
