A mapping review of randomized controlled trials in the spinal cord injury research literature

Study design Mapping Review. Objective The objective of this study was to map out and characterize the quantity and quality of all published spinal cord injury (SCI) randomized controlled trials (RCTs) with respect to number, sample size, and methodological quality between January 1970 and December 2016. Setting Not applicable. Methods A literature search of multiple research databases was conducted. Studies adhering to the following criteria were included: the research design was an RCT; written in English; participants were >18 years; and the sample was >50% SCI. Data were extracted pertaining to author(s), year of publication, country of origin, initial and final sample size, intervention, and control. Methodological quality was assessed using the Physiotherapy Evidence Database (PEDro) tool. Data was assessed overall and by each year of publication. Results In total, 466 RCTs were published 1971-2016 on 29 primary topic areas, with Bladder (n = 78, 16.7%) most common, followed by Pain (n = 54, 11.6%), and Lower Limb (n = 45, 9.7%). Studies were published in 172 unique journals, with the most common being Spinal Cord (n= 68, 14.6%). The most common producer of studies was the United States (n = 191, 41.0%). RCT publications increased linearly until 2012 when the rate tripled, resulting in 40.8% published 2012-2016. A total of 247 (59.4%) RCTs had <30 subjects; there was no change in sample size over time (p = 0.770). The overall mean PEDro score was 5.56 (1.68); scores improved from 5.0 (1.4) in 1976 to 6.3 (1.9) in 2016 (F= 2.230, p < 0.001). Conclusions The number of SCI RCTs and their associated sample size remains low; however, methodological quality has improved over time.