PRIMARY END-POINTS IN PHASE-III CLINICAL-TRIALS OF SEVERE HEAD TRAUMA- DRS VERSUS GOS

The most commonly used primary end point in phase III clinical trials of severe head trauma is the Glasgow Outcome Scale (GOS), usually dich otomized to favorable (good) and unfavorable (poor) outcomes. The alte rnative endpoints include the Disability Rating Scale (DRS) with a 31- point scale, The purpose of this study was to compare DRS and GOS usin g the data collected from two completed clinical trials organized by t he American Brain Injury Consortium and two pharmaceutical companies, The two outcome scales were examined and compared in terms of the corr elation between the two scales, sensitivity, and p values between the differences between two arms of the trials. There was no indication th at the DRS was more sensitive or advantageous relative to the dichotom ized or four-category GOS, In addition, the highly significant correla tion between the two outcome scales (r = 0.95; p < 0.0001) could not j ustify the DRS as an end point. The other problems with the DRS includ e the difficulty of determining the clinically meaningful difference i n designing trials, The study suggested that the GOS is a better prima ry end point than DRS.