Treatment benefits of duloxetine in major depressive disorder as assessed by number needed to treat

Abstract

The efficacy of an antidepressant typically is assessed by comparing it with placebo using a validated rating scale. This type of analysis, however, does not translate well to the clinical settings. For clinicians, a more meaningful measure is the number needed to treat (NNT). The objective of this analysis is to assess the efficacy of duloxetine in terms of NNT. Data were obtained from nine clinical trials designed to assess the efficacy and safety of duloxetine as a treatment for major depressive disorder. These studies examined 8-9 weeks of acute treatment with duloxetine. NNT estimates were determined for duloxetine, selective serotonin reuptake inhibitor comparators from six multi-dose studies, and for duloxetine in patients > or =65 years of age. The NNT was based on the Hamilton Depression Rating Scale (HAMD17) for response and remission, and improvements defined by the Clinical Global Impression (CGI) were estimated and compared. The NNT was favorable for both duloxetine and selective serotonin reuptake inhibitor compared with placebo. The patients receiving duloxetine had NNT for HAMD17 response of 6.0, remission 7-9, and CGI-defined improvement 6-7 by 8 weeks. The NNTs for selective serotonin reuptake inhibitors (fluoxetine or paroxetine, 20 mg/day) were around 7 for response, 11 for remission, and 8 for CGI-defined improvement. The NNTs in the elderly were similar. The NNT for several measures of efficacy including remission consistently demonstrated the treatment benefits of duloxetine as well as of fluoxetine and paroxetine compared with placebo.