Growth and decentralization of the medical literature: implications for evidence-based medicine.

This article examines trends in the volume, authorship, content, and funding of MEDLINE articles between 1978 and 2001, a time of great change in medical research and medical practice. The authors examine these trends as a means of identifying opportunities and challenges for using this information to guide practice. A total of 8.1 million journal articles were published in MEDLINE between 1978 and 2001. Between 1978 to 1985 and 1994 to 2001, the annual number of MEDLINE articles increased 46%, from an average of 272,344 to 442,756 per year, and the total number of pages increased from 1.88 million pages per year during 1978 to 1985 to 2.79 million pages per year between 1994 to 2001. The growing number of articles, the shift toward clinical topics, and the growth of randomized trials point to an increasingly rich source of information available for guiding treatment decisions. However, this stunning growth in medical information also brings challenges and risks. Furthermore, MEDLINE-indexed journals represent an increasingly small portion of the broader universe of medical information.