Introduction/Objective: To investigate reporting of randomised controlled trials (RCTs) in general health care journals over the last 50 years, with particular reference to the distribution and size of RCTs over time.
Methods: One general health care journal, (usually that of the national medical association), from each of the following countries - Australia, Austria, Denmark, France, Germany, Italy, Ireland, The Netherlands, New Zealand, South Africa, Spain, Switzerland, UK and USA has been searched for reports of RCTs. Information about the number of randomised participants will be extracted for each trial. Data from the journals will be pooled, and the trends over time analysed.
Results: More than 4,000 published trials have so far been identified from 12 of these journals. Preliminary results from the BMJ, Deutsche Medizinische Wochenschrift, New Zealand Medical Journal and South African Medical Journal, show more than a 10-fold increase in the annual number of trial reports between the eariy 1950s and the early 1980s. However, the number has subsequently decreased and, in the early 1990s, just over half as many reports of RCTs appeared in these journals compared to the eariy 1980s. This decrease does not appear to be explained by an increase in the size of the published trials.
Discussion: The decline in the number of RCTs published in general health care journals may be due to a number of factors; a genuine downward trend in the number of RCTs being conducted; an increased tendency not to publish the results; or an increased tendency for them to be published in specialised journals. However, the decline needs to be borne in mind by all those wishing to use the findings of RCTs as a basis for determining appropriate forms of care. Whatever the reason for the trend, it provides further evidence that sources beyond these widely available journals need to be considered.