Jenkins, Gregory

Objective The study aimed to define thresholds of clinically significant change in 17‐item Hamilton Depression Rating Scale (HDRS‐17) scores using the Clinical Global Impression‐Improvement (CGI‐I) Scale as a gold standard. Methods We conducted a secondary analysis of individual patient data from the Pharmacogenomic Research Network Antidepressant Medication Pharmacogenomic Study, an 8‐week, single‐arm clinical trial of citalopram or escitalopram treatment of adults with major depression. We used equipercentile linking to identify levels of absolute and percent change in HDRS‐17 scores that equated with scores on the CGI‐I at 4 and 8 weeks. Additional analyses equated changes in the HDRS‐7 and Bech‐6 scale scores with CGI‐I scores. Results A CGI‐I score of 2 (much improved) corresponded to an absolute decrease (improvement) in HDRS‐17 total score of 11 points and a percent decrease of 50–57%, from baseline values. Similar results were observed for percent change in HDRS‐7 and Bech‐6 scores. Larger absolute (but not percent) decreases in HDRS‐17 scores equated with CGI‐I scores of 2 in persons with higher baseline depression severity. Conclusions Our results support the consensus definition of response based on HDRS‐17 scores ( > 50% decrease from baseline). A similar definition of response may apply to the HDRS‐7 and Bech‐6. Copyright © 2016 John Wiley & Sons, Ltd.