[Evolution of epidemiological methods in clinical research in Spain (1975-1994)]

Previous studies have shown a sparing utilization of analytical and experimental designs in Spanish clinical research journals. The study aims are to compare among countries, the use of epidemiologic method in articles published in scientific journals, and to determine the extent to which this research has direct funding.

Cross-sectional study including all original papers published during 1994 in Medicina Clinica [(Med Clin (Barc)], Revista Clinica Española (Rev Clin Esp), The Lancet (Lancet) and New England Journal of Medicine (N Engl J Med). They were classified according to epidemiological design and we verified the financial support mention.

594 papers were included. Epidemiological studies without control group prevailed in Spanish journals. The most common designs were descriptive studies in Med Clin (Barc), with 45.5%, and clinical series in Rev Clin Esp, with 41.7%. The 33.6% of original papers published in Lancet and 28.4% of N England J Med were randomized trials. We found information about financial support in 73.7% of papers published in Lancet, in 77.4% of N Engl J Med, in 23.1% of Med Clin (Barc) papers and not one in the Rev Clin Esp studies.

In Spanish clinical journals the use of epidemiological methods with control group is limited and direct financial support unusual. Wherefore these studies have a limited applicability.