Identification and description of the clinical trials published in Spanish journals of general and internal medicine during the period 1971-1995

Article type
Authors
Marti J
Abstract
Introduction/Objective: To identify and to describe the Controlled Clinical Trials (CCT) published in the all Spanish journals of General and Internal Medicine during the period 1971-1995.

Methods: Descriptive field study. A) Identification of the publications. The following sources of information have been utilized: 1. Indice Medico Espanol (IME), principal national registry that includes publications in Spanish health sciences journals for the period 1971-1995; 2. Consultation of the CD-ROM catalog (C17) of periodicals that are found in the Spanish health sciences libraries (CINDOC 1996); 3. Consultation of the collective catalogs of health sciences periodicals; 4. Others (personal reports). B) Identification of the CCT. They have been identified through a systematic manual search in each issue of the journals. C) Extraction of the information. D) Classification and descriptive analysis, based on the principal variables of interest.

Results: A) A total of 69 journals of General and Internal Medicine have Been identified, using the following sources of information: 1) IME: 42 (60.9%); 2) C-17: 9 (13%); 3) Collective Catalogs of Periodicals in Health Sciences: 14 (20.3%); 4) Other, informal means: 4 (5.8%). B) A total of 417 CCT have been identified in the 69 journals identified published between 1971 and 1995. D) 1. Type of publication: 286 CCT (68.6%) original articles, 113 (27%) presentations to congresses, 16 (3.8%) letters to the editor and 2 (0.5%) prior communications. 2. The date of realization was not published in 364 CCT (87%). 3. The 3 most investigated health problems were: arterial hypertension (40 CCT, 9.6%), asthma (with 22 CCT, 5.3%) and chronic obstructive pulmonary disease - COPD - (with 20 CCT, 4.8%). 4. Interventions studied: 329 pharmacological CCT (78.9%), 68 non-pharmacological CCT (16.3%), combinations of pharmacological with non-pharmacological treatment in 20 CCT (4.8%). 5. Random allocation method: 380 (91.1%) they have been CCT and 37 (8.9%) RCT. 6. Blinding: 154 CCT (36.9%) were double-blind and 22 (5.2%) blind or single blind. 19 CCT were described as open (4.5%). 222 CCT did not mention any type of method for blinding the study (53.2%).

Discussion: A) The identification of all the CCT published in the Spanish journals of General and Internal Medicine will be used to facilitate access to this type of information for Cochrane Review Groups. B) The study of the data is going to make it possible to analyze policies for development and publication of CCTs in Spain