Predictors of Citation Rates in High Impact Glioblastoma Trials

Abstract Background Clinical trials are at the top of research study designs and tend to attract high citation numbers. Glioblastoma multiforme (GBM) is a multidisciplinary disease that continues to be the subject of peak research interest. The literature relating to predictors of citation rates in clinical trials in general remains limited. We aim to identify the factors that influence citation numbers in high impact GBM trials. Methods The 100 most cited published GBM trials were identified and reviewed. The primary analysis was correlating articles citation numbers with various trial and publication-related predictors using Pearson correlation coefficient. The secondary analysis was comparing the mean citation numbers for the different subgroups using mean difference test. Results The median (range) citation numbers for the selected 100 trials were 349 (135- 16384). The primary analysis showed significant correlation between articles citation numbers and study population (P=0.024), trial phase (P=0.0427) and journal’s IF (P<0.0001). The secondary analysis demonstrated significantly higher mean citation numbers in trials with the following features: study population ≥ 115 (P=0.0208), phase III (P=0.0372), treatment protocol that included radiotherapy (RT) (P=0.0189) and temozolomide (TMZ) (P=0.0343), journal’s IF ≥ 14.9 (P=0.02) and general medical journals (P=0.28). Conclusions The most significant predictors of citation rates in high impact GBM trials were study population, trial phase, and journal IF. The treatment protocol was a positive predictor when it included the currently widely accepted treatment modalities (RT and TZM). Randomization, age of publication as well as the numbers of arms, authors, centres, countries, and references were not significant predictors. Increasing awareness of the factors that could affect citations may be useful to researchers undertaking clinical trials.