Site Versus Centralized Raters in a Clinical Depression Trial
Impact on Patient Selection and Placebo Response
Kenneth A. Kobak, PhD,* Andrew Leuchter, MD,Þ David DeBrota, MD,þ Nina Engelhardt, PhD,* Janet B.W. Williams, DSW,*§ Ian A. Cook, MD,Þ Andrew C. Leon, PhD,|| and Jonathan Alpert, MD, PhD¶
Abstract: The use of centralized raters who are remotely linked to sites and interview patients via videoconferencing or teleconferencing has been suggested as a way to improve interrater reliability and interview quality. This study compared the effect of site-based and centralized ratings on patient selection and placebo response in subjects with major depressive disorder. Subjects in a 2-center placebo and active compar- ator controlled depression trial were interviewed twice at each of 3 time points: baseline, 1-week postbaseline, and end pointVonce by the site rater and once remotely via videoconference by a centralized rater. Raters were blind to each others’ scores. A site-based score of greater than 17 on the 17-item Hamilton Depression Rating Scale (HDRS-17) was required for study entry. When examining all subjects entering the study, site-based raters’ HDRS-17 scores were signicantly higher than centralized raters’ at baseline and postbaseline but not at end point. At baseline, 35% of subjects given an HDRS-17 total score of greater than 17 by a site rater were given an HDRS total score of lower than 17 by a centralized rater and would have been ineligible to enter the study if the centralized rater’s score was used to determine study entry. The mean placebo change for site raters (7.52) was signicantly greater than the mean placebo change for centralized raters (3.18, P G 0.001). Twenty- eight percent were placebo responders (950% reduction in HDRS) based on site ratings versus 14% for central ratings (P G 0.001). When ex- amining data only from those subjects whom site and centralized raters agreed were eligible for the study, there was no signicant difference in the HDRS-17 scores. Findings suggest that the use of centralized raters could signicantly change the study sample in a major depressive dis- order trial and lead to signicantly less change in mood ratings among those randomized to placebo.
Key Words: clinical trials, randomized, placebo effect, methods, outcomes assessments, patient, depressive disorder, Hamilton Depression Rating Scale