Impact factor and electronic versions of biomedical scientific journals.

BACKGROUND AND OBJECTIVES: The development of electronic editions of scientific journals and the rapid spread of scientific information might modify the pattern the bibliographic citations, and thus the impact factor and quality of journals. We assessed changes in the impact factor over years of a number of journals and whether the presence of an electronic version of the journal was associated with the impact factor score. DESIGN AND METHODS: This is a retrospective longitudinal study. The availability of journals (table of contents (TOC), abstracts, full text and free full text) on Internet, in years 1995-2000, was assessed between December 2000 and January 2001. The first 20 top-journals from 8 subject categories were included. Changes in impact factor over time and association with Internet availability were modeled. RESULTS: Overall, 118/139 journals (85%) had their TOC on the Internet, of these 107 (77%) had abstracts, 97 (70%) had full text and 33 (24%) free full text. The median impact factor for all journals was 1.65, 2.08, 2.10, 2.21 and 2.35 for the years from 1995 to 1999, respectively. This increase was statistically significant, with differences among subject categories. The presence of TOC, abstracts and full text on the Internet was also significantly associated with higher impact factor, after accounting for time and subject category. INTERPRETATION AND CONCLUSIONS: The impact factor has been used for assessing the quality of journals. We identified a new limitation of this indicator: the impact factor seems to be related to the amount of circulation of information through Internet. This could be a temporary limitation, associated with diffusion of journals on, and spread of Internet.

Searching for rehabilitation articles on MEDLINE and EMBASE. An example with cross-over design.

OBJECTIVE: To analyze the usefulness of MEDLINE and EMBASE biomedical databases in rehabilitation and to identify descriptors and text words necessary to do a comprehensive search. METHODS: We looked for articles published since 1990 relating to neurologic, orthopedic, respiratory, urologic, and rheumatologic rehabilitation. We looked for all descriptors and text words pertinent to rehabilitation and linked them with "cross-over." RESULTS: We found 165 articles in MEDLINE and 159 in EMBASE with an overlap of only 17% of articles. Only 32% of the articles in MEDLINE and 35% in EMBASE were relevant. Of the 214 nonoverlapping articles, 84% were published in journals present in both databases, but were indexed differently. CONCLUSION: At least two databases must be used to ensure a comprehensive literature search. Searching in EMBASE after MEDLINE we gained 25 articles (32%). Bibliographic search in rehabilitation is particularly complex because of the heterogeneity of the subject matter. Cooperation between an information professional and a clinician is essential to ensure a comprehensive search.

Evidence-based medicine and practice: what's new for the physicians?

This paper introduces the readers to the concepts of Evidence-Based Medicine (EBM) and Evidence-Based Health Care (EBHC). After taking the view that EBM and EBHC are essentially a new way of thinking about the theory and practice of medicine, the paper discusses their potential, limitation and ambiguities. Besides summarising the roles of EBM and EBHC in providing information relevant for patient care, medical education, health policy-making, information-seeking and eventually, guideline production, the paper closes discussing some of the potentials as well as dangers of this new scientific and cultural movement.

Cytotoxic and hormonal treatment for metastatic breast cancer: a systematic review of published randomized trials involving 31,510 women.

PURPOSE: A systematic review of randomized clinical trials (RCTs) was undertaken to assess the effectiveness of medical treatment for metastatic breast cancer. METHODS: RCTs published between 1975 and 1997 have been classified according to 12 therapeutic comparisons: (1) polychemotherapy (PCHT) agents versus single agent; (2) PCHT regimens with anthracycline versus PCHT without anthracycline; (3) other PCHT versus cyclophosphamide, methotrexate, and fluorouracil (CMF); (4) chemotherapy (CHT) with epirubicin versus CHT with doxorubicin; (5) CHT versus same CHT delivered with less intensive schedules; (6) other endocrine therapy (OET) versus tamoxifen; (7) OET plus tamoxifen versus tamoxifen alone; (8) OET versus medroxyprogesterone; (9) OET versus aromatase inhibitors; (10) OET versus megestrol; (11) endocrine therapy (ET) versus same ET at lower doses; and (12) CHT plus ET versus CHT. Tumor response rates, mortality hazards ratio (HR) and frequency of severe side effects were the outcome measures. RESULTS: A total of 189 eligible trials (31,510 patients) were identified. All provided response rates and 133 (70%) data or survival curves needed for calculation of the HR. In eight of 12 comparisons, statistically significant differences for response emerged (1, 2, 3, 5, 7, 8, 11, 12); all but no. 8 favored the first term of the comparison. Overall survival analysis showed better results of (a) PCHT versus single-agent CHT (HR=0.82; 95% confidence interval [CI], 0.75 to 0.90); (b) CHT with doxorubicin versus CHT with epirubicin (HR=1.13; 95% CI, 1.00 to 1.27); (c) CHT versus the same CHT delivered with less intensive schedules (HR=0.90; 95% CI, 0.83 to 0.97); (d) ET versus the same ET at lower doses (HR=0.86; 95% CI, 0.77 to 0.97). Quality of life was measured in only 2,995 of 31,510 patients (9.5%). CONCLUSION: Despite some evidence of effectiveness of specific regimens, the relevance of these findings is limited by the modest survival benefit and the lack of evaluation of the quality-of-life impact of these treatments.

Placental perfusion. An overview of the literature.

Placental perfusion techniques are currently used to study not only the organ functions but also the transfer profile and metabolic pathway of different compounds. In view of the interest in the mechanism of transfer and potential adverse effects of compounds there are numerous publications on the topic, but no systematic picture is yet available. Thus an overview has been made of all studies published from 1966 to 1990 that use this experimental approach. Out of 359 computer-retrieved articles, 266 (74%) actually dealt with the target topic; 68 articles were added after a systematic hand search, so a total of 334 articles were analyzed. The distribution of papers per year was constant until 1980, and rose significantly thereafter. Animal studies using placental perfusion were performed either in situ or in vitro, whereas human investigations were mostly examined by in vitro perfusion techniques. Animal experiments were done on seven species, the guinea pig being the most widely used. The aims of all studies could be divided into five main categories: 132 studies researched the kinetics of compounds in the placenta; 100 studies investigated placental metabolism; methodology of perfusion was reported in 22 articles; and 49 studies examined physiological changes of placental variables. A clear increase in pharmacological studies was noted starting from 1986 (there were 31 such studies). Compounds studied were either endogenous or exogenous. Almost all endogenous compounds were investigated, some of them quite extensively (mainly hormones, angiotensin, glucose, and lactate). There seemed to be no preferential field for exogenous compounds (62 compounds could be assigned to 20 classes).(ABSTRACT TRUNCATED AT 250 WORDS)

Prevención farmacológica de la otitis media aguda recurrente / Pharmacological prevention of the recurrent acute otitis media

El presente trabajo se de sarrolló en dos fases: en la primera los pdiatras respondieron a preguntas de un cuestionario, para poner en evidencia los tratamientos personales practicados en caso de Otitis Media Aguda (OMA) así como otitis media concaracter recurrente (ver cuadro 1). La segunda fase del trabajo consiste en evaluar críticamente cada uno de los estudios clínicos publicados sobre prevención farmacológica de OMAR y discutirlos en encuentros formales, de caracter colegial

A computer filing system for drug use in a pregnancy consultation service.

A computerized database for documenting drug use in pregnancy was set up on a personal computer. Summaries of the information available from the literature on more than 700 drugs taken during pregnancy have already been entered and are currently in use. This reliable, cheap, handy, and personal system (the first available on the topic) may be a potentially useful instrument not only for drug consultation services, but for individual physicians, too.

Critical review of the quality and development of randomized clinical trials (RCTs) and their influence on the treatment of advanced epithelial ovarian cancer.

Trials on chemotherapy of advanced ovarian cancer published between 1975-88 were systematically reviewed for quality (according to the method of Chalmers) and consistency of tested hypotheses with a view to a meta-analysis of all published studies in the field. Median overall, internal and external validity scores were 47%, 43% and 53%, respectively. No association was found between scores and key features of trials, such as percentage studies with significant results in response or survival or percentage studies with high or low follow-up retention (withdrawal rates less than or greater than or equal to 15%). Only 21% of trials reported a fully blind randomization procedure and only in 13% were drop-outs accounted for by the intent-to-treat method. Only 4 trials entered more than 150 patients per arm, a sample size consistent with detection of an absolute difference of 11% in mortality. The majority of trials (58%) investigated the role of combination regimens versus a single-agent control arm. The remaining trials tested different polychemotherapies. However, within these two general issues, treatment options were quite heterogeneous: seven subgroups were identified by whether cisplatin was present in either the treatment or the control arm. We conclude that the internal coherence and development of randomized clinical trials in advanced ovarian cancer and their methodologic soundness are quite poor. In this situation meta-analysis cannot go beyond a systematic attempt to answer a very general "treatment effectiveness" question.