[e-drug] publication bias on major global diseases

[e-drug@healthnet.org]

E-DRUG: publication bias on major global diseases
-------------------------------------------------
[Not directly related to essential drugs, but very relevant for generation
of evidence: publication bias. So now we don't only have "neglected
diseases" but also "unpublishable diseases"? Thanks to Valeria for spotting.
Copied as fair use.
The original CMAJ article is freely available at:
http://www.cmaj.ca/cgi/content/full/170/11/1673 WB]

BMJ  2004;328:1337 (5 June), doi:10.1136/bmj.328.7452.1337-a

News roundup

Medical journals don't publish trials on major global diseases

Toronto David Spurgeon

Few randomised controlled trials published in leading general
medical journals address the major health problems that affect
most of the world?s poor people.

An analysis of trials published in six leading general medical
journals in 1999 shows that only 14 of 90 trials (16%) that looked
at at least one of the top 10 causes of the global burden of
disease were highly relevant to international health, as assessed
by World Health Organization criteria (CMAJ 2004;170:1673-7).
Seven of the 35 most deadly and debilitating diseases were not
studied in any published trial.

The journals in the analysis were Annals of Internal Medicine, BMJ,
JAMA (the journal of the American Medical Association), Lancet,
New England Journal of Medicine, and CMAJ (the journal of the
Canadian Medical Association).

Of the 286 randomised controlled trials published, 124 (43%)
addressed one of 35 major diseases. Of these diseases
ischemic heart disease, HIV and AIDS, and cerebrovascular
disease were the most commonly studied. Ninety trials (32%)
covered one of the top 10 leading causes of disease in the world.

Twelve experts from international health organisations rated the
studies for relevance to international health. The mean rating was
2.6 (standard deviation 1.5) out of 5.0. Only 14 (16%) of the 90
trials were rated as 4.0 or more, indicating high relevance to
international health. Almost half of the 40 leading causes of the
global burden of disease were not studied in any trial.

The authors note that more than two thirds of the world?s
population live in low income countries, where health priorities
differ from more affluent parts of the world. The most impoverished
20% of the world?s people are nine times more likely to die of
infectious disease and 10 times more likely to die in childhood
than people living in rich nations.

The Global Forum for Health Research estimates that less than
10% of spending on health research is directed toward diseases
or conditions that account for 90% of the global burden of disease,
a phenomenon referred to as the ?10/90 gap.?

Lack of relevant research, difficulties with the publication process,
such as an inability to write in English, editorial bias in favour of
the interests of Western culture, and restricted access to scientific
information may all be to blame, researchers in developing
countries have said.

In an accompanying commentary Dr Prabhat Jha, director of
Toronto?s St Michael?s Hospital Centre for Global Health
Research, and colleagues say that much more research should
be done into the few major diseases that account for the gap
between rich and poor countries so that mortality and morbidity
among the world?s poor people can be reduced (CMAJ
2004;170:1687-8).

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