Quality and quantity of research publications by Iranian neurosurgeons: Signs of scientific progress over the past decades

BACKGROUND: This is an analysis of papers published by Iranian neurosurgeons while working in Iran until the year 2010. METHODS: We collected bibliometric data and assigned a level of evidence (LOE) for each paper and compared neurosurgical research productivity across three time periods (before 1990, between 1991 and 2000, and after 2000). For further illustration, the annual growth rates of Iranian publications were calculated for all papers published after 1995. RESULTS: We found a total of 1196 papers by 422 Iranian neurosurgeons. Five authors accounted for 22.9% of the papers. The average number of authors for each published manuscript was 3.48 and increased significantly from 2.0 to 4.0 across the three investigated periods (P < 0.001). 58.9% of Iranian papers were published in local journals only. A total of 74.6% articles were published after 2000, which was a significant increase compared with the decades before (P < 0.001). Original articles and case reports accounted for 63.8% and 31.1% of the publications, respectively. The proportion of case reports decreased while the proportion of original articles increased across the three time periods (P < 0.001). The adjusted growth rate for the total number of publications, original articles, case reports, clinical trials, and randomized clinical trials (RCTs) were 14.4%, 16.6%, 10.7%, 13.46%, and 14.7% per year, respectively. Overall, the four most frequently investigated topics were spine (27.3%), trauma (22.3%), tumor (19.1%), and vascular diseases (13.5%). The mean impact factor for journals publishing these studies and average number of citations for each paper (obtained from web of science) were found to be 1.2 and 5.46, respectively. A partitioning of these publications into assigned categories reflecting the LOE of each paper yielded the following LOE distribution for all assessed publications: Ib: 6.02%, Ic: 0.3%, IIa: 0.2%, IIb: 5.4%, IIc: 0.41%, IIIb: 4.8%, IV: 22.5%, and V: 1.2%. The relative number of publications categorized into higher LOE classes increased over the three investigated periods (P = 0.003). Based on growth curve model, the rate of increase in total numbers of publications following each position change from nonuniversity affiliated neurosurgeon to university affiliated and from university affiliated neurosurgeon to chairman university affiliated neurosurgeon was 81%. CONCLUSIONS: A considerable increase in amount and quality of Iranian papers was observed during the past decade as reflected in a higher number of papers categorized in upper LOE classes.