People in sub-Saharan Africa carry the heaviest burden of HIV and AIDS, yet very few trials have been conducted on the African continent over the past two decades, say researchers in this week's BMJ.

This study confirms previous findings that HIV/AIDS trials are under-represented in sub-Saharan research and suggests that publication of trial results continues to be driven by researchers external to the continent.

The team identified and mapped all randomised controlled trials on HIV and AIDS conducted wholly or partly in Africa and reported before 2004.

After extensive searching, they identified 77 trials published or reported from 1987 to 2003.

Most of the trials were funded by government agencies outside Africa, pharmaceutical companies and international non-government or inter-government organisations. Few principal investigators were based in African countries and there was no mention of ethical approval or informed consent in 19 and 17 trials, respectively.

The relatively small number of HIV/AIDS trials conducted in Africa is not commensurate with the burden of disease, say the authors. This may reflect a lack of economic ability, political will, or research capacity.

Geographical mapping as an adjunct to prospective trial registration is a useful tool for researchers and decision makers to track existing and future trials, they conclude.