Positive Outcomes Influence the Rate and Time to Publication, but Not the Impact Factor of Publications of Clinical Trial ResultsReport as inadecuate




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Objectives

Publication bias may affect the validity of evidence based medical decisions. The aim of this study is to assess whether research outcomes affect the dissemination of clinical trial findings, in terms of rate, time to publication, and impact factor of journal publications.

Methods and Findings

All drug-evaluating clinical trials submitted to and approved by a general hospital ethics committee between 1997 and 2004 were prospectively followed to analyze their fate and publication. Published articles were identified by searching Pubmed and other electronic databases. Clinical study final reports submitted to the ethics committee, final reports synopses available online and meeting abstracts were also considered as sources of study results. Study outcomes were classified as positive when statistical significance favoring experimental drug was achieved, negative when no statistical significance was achieved or it favored control drug and descriptive for non-controlled studies. Time to publication was defined as time from study closure to publication. A survival analysis was performed using a Cox regression model to analyze time to publication. Journal impact factors of identified publications were recorded. Publication rate was 48·4% 380-785. Study results were identified for 68·9% of all completed clinical trials 541-785. Publication rate was 84·9% 180-212 for studies with results classified as positive and 68·9% 128-186 for studies with results classified as negative p<0·001. Median time to publication was 2·09 years IC95 1·61–2·56 for studies with results classified as positive and 3·21 years IC95 2·69–3·70 for studies with results classified as negative hazard ratio 1·99 IC95 1·55–2·55. No differences were found in publication impact factor between positive median 6·308, interquartile range: 3·141–28·409 and negative result studies median 8·266, interquartile range: 4·135–17·157.

Conclusions

Clinical trials with positive outcomes have significantly higher rates and shorter times to publication than those with negative results. However, no differences have been found in terms of impact factor.



Author: Pilar Suñé , Josep Maria Suñé, J. Bruno Montoro

Source: http://plos.srce.hr/



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