Comparison of the distribution of citations received by articles published in high, moderate, and low impact factor journals in clinical medicine.

BACKGROUND: Whether the journal impact factor (JIF) indicator reflects the number of citations to an average article of a journal in different subject categories is controversial. We sought to further investigate this issue in general and internal medicine journals. METHODS: We selected to evaluate three journals of the above subject category, in each of three different JIF levels (high: 15.5-28.6, moderate: 4.4-4.9 and low: 1.6). Using the Scopus database, we retrieved the original research articles (after detailed screening) and review articles (as classified by Scopus) that were published in the selected journals in 2005 along with the number of citations they received in 2006 and 2007. We pooled the citations for articles of the same type in journals with the same JIF level into distinct variables. RESULTS: There was no marked association between the distribution of citations per article published in general medical journals and their JIF. All distributions studied were skewed to the right (higher number of citations). Specifically, 16-22% of the original research articles accounted for 50% of the total citations to this type of article for all three categories of studied journals; 34-37% of original research articles accounted for 75% of citations. The respective values for review articles were 12-18% and 29-39%. CONCLUSION: The distribution of citations received by articles published in high, moderate and low impact factor journals in clinical medicine seems similar. The JIF is not an accurate indicator of the citations the average article receives; articles published in low impact factor journals can still be highly cited and vice versa.

Tuberculosis and malignancy.

BACKGROUND: Tuberculosis (TB) and malignancy represent global threats claiming millions of lives and inflicting formidable suffering worldwide. Surprisingly, the pathophysiological and practical implications of their co-existence have received little attention. METHODS: Therefore, we sought to review the available literature on the field and identify data regarding the association between TB and malignancy in order to highlight the neglected aspects of this association and probably derive clinically useful information. We searched PubMed up to June 2008 for case reports, case series, non-comparative and comparative studies that were written in English and reported data on the occurrence of both TB infection and a neoplastic disorder in the same patient(s). The development of mycobacterial infections in patients with immunocompromized conditions is well known and was considered outside the scope of this review. EVIDENCE SYNTHESIS: The synthesis of the available evidence enabled us to establish three different types of association between malignancy and TB: (i) the development of cancer on the background of a previous tuberculous infection; (ii) the concurrent existence of TB and malignancy in the same patient(s) or clinical specimen(s); and (iii) the diagnostic challenges arising from the multi-faceted presentations of these two disorders. CONCLUSION: We conclude that clinicians need to be aware of the protean manifestations of TB and cancer and maintain a high index of suspicion for simultaneous and/or misleading presentations. In addition, further research is required to determine if a tuberculous infection, being similar to other chronic infections and inflammatory conditions, may facilitate carcinogenesis.