Leading causes of 'global' death and disability not being studied in clinical trials

Toronto, CANADA – Many of the most deadly and debilitating diseases experienced by much of the world’s population are strikingly under-represented in clinical trials that are published in leading international general medical journals.

A new study, published in the May 25th Canadian Medical Association Journal has found a wide mismatch between diseases and conditions that affect much of the world’s population and those studied in randomized control trials (RCTs) published in major medical journals over a one-year period. Many of the RCTs reviewed in this study were drug trials.

“We know how people live and die on the other side of the world, yet we’re not studying the therapies that can reduce their disability and mortality,” says lead investigator Dr. Paula Rochon, a geriatrician and senior scientist at the Kunin-Lunenfeld Applied Research Unit at Baycrest Centre for Geriatric Care.

The Global Forum for Health Research has estimated that less than 10% of health research spending is directed toward diseases or conditions that account for 90% of the global burden of disease, a phenomenon known as the “10/90 gap”.

Dr. Rochon and her colleagues conducted a MEDLINE search of RCTs published in six leading international, peer-reviewed general medical journals in 1999. The journals included The Lancet, the Annals of Internal Medicine, the British Medical Journal, the Journal of the American Medical Association, the New England Journal of Medicine, and the Canadian Medical Association Journal.

Of the 286 RCTs in the sample:

• Fewer than half (43%) addressed one of the 35 leading causes of the global burden of disease;
• Leading causes such as malnutrition and measles were not studied by any trial. Malaria, tuberculosis and diarrhea were studied in only a few.
• Almost one quarter of the RCTs (21%) focused on the three most common conditions – ischaemic heart disease, HIV/AIDS and cerebrovascular disease.

To provide a practical perspective, 12 experts associated with international health organizations were asked to rate the international health relevance of the RCTs that did study one of the Top 10 causes of the global burden of disease. Eleven of the 12 were physicians associated with organizations such as the World Health Organization, the International Clinical Epidemiology Network (INCLEN) and Doctors Without Borders.

Overall, the experts rated most of the studies as having little relevance to international health – that is, the studies’ findings would not lead to practical therapeutic solutions. For example, a therapy may be beneficial but very costly, making it beyond the reach of most people living in a low-income country.

Dr. Rochon points to the work of grassroots organizations that are dedicated to providing doctors and researchers living in developing countries with the skills and training to conduct their own RCTs based on what they know is needed and feasible in terms of practical, cost-effective therapeutic strategies. It may be thatMore western-based research is not the answer, suggests Dr. Rochon. “Those living and working in a developing country clearly have a richer appreciation of the solutions that will work in their environment,” she says.

Another important strategy is to haveMore global burden of disease studies published in the major medical journals because they may be easier to access by doctors around the world, says Dr. Rochon. However, difficulties with writing in a second language (such as English) as well as the lack of access to scientific information are continuing hurdles.

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Dr. Rochon has published previous studies looking at the under-representation of older women in clinical drug trials, the under-representation generally of older adults in research, and the under-prescribing of beneficial beta-blocker treatment for older heart attack patients.

This current study in the Canadian Medical Association Journal was funded by the Kunin-Lunenfeld Applied Research Unit at Baycrest Centre for Geriatric Care. Baycrest is an internationally-renowned academic health sciences centre affiliated with the University of Toronto.