What does the MADRS mean? Equipercentile linking with the CGI using a company database of mirtazapine studies

Background: Little is known about the clinical relevance of the Montgomery Asberg Depression Rating Scale (MADRS) total scores. It is unclear how total scores translate into clinical severity, or how commonly used measures for response (reduction from baseline of >= 50% in the total score) translate into clinical relevance. Moreover, MADRS based definitions of remission vary. Methods: We therefore compared: a/ the MADRS total score with the Clinical Global Impression Severity Score (CGI-S) b/ the percentage and absolute change in the MADRS total scores with Clinical Global Impression Improvement (CGI-I); c/ the absolute and percentage change in the MADRS total scores with CGI-S absolute change. The method used was equipercentile linking of MADRS and CGI ratings from 22 drug trials in patients with Major Depressive Disorder (MDD) (n=3288). Results: Our results confirm the validity of the commonly used measures for response in MDD trials: a CGI-I score of 2 ('much improved') corresponded to a percentage MADRS reduction from baseline of 48-57%, and a CGI-I score of 1 ('very much improved') to a reduction of 80-84%. If a state of almost complete absence of symptoms were required for a definition of remission, a MADRS total score would be < 8, because such scores corresponded to a CGI-S score of 2 ('borderline mentally ill'). Limitations: Although our analysis is based on a large number of patients, the original trials were not specifically designed to examine our research question. Conclusions: The results might contribute to a better understanding and improved interpretation of clinical trial results in MDD.