Primary research

An analysis of correlations among four outcome scales employed in clinical trials of patients with major depressive disorder

Qin Jiang and Saeeduddin Ahmed

Wyeth Research, Collegeville, Pennsylvania, PA, USA

author email corresponding author email

Annals of General Psychiatry 2009, 8:4doi:10.1186/1744-859X-8-4

Published:	23 January 2009

Abstract

Background

The 17-item Hamilton Depression Rating Scale (HAM-D₁₇) remains the 'gold standard' for measuring treatment outcomes in clinical trials of depressed patients. The Montgomery Ǻsberg Depression Rating Scale (MADRS), Clinical Global Impressions-Severity (CGI-S) and -Improvement (CGI-I) scales are also widely used.

Objective

This analysis of data from 22 double-blind, placebo-controlled clinical studies of venlafaxine in adult patients with major depressive disorder was aimed at assessing correlations among these 4 scales.

Methods

Changes from baseline for MADRS, HAM-D₁₇ and CGI-S, and end point CGI-I scores and response (≥50% decrease from baseline HAM-D₁₇ or MADRS, or CGI-S or CGI-I score ≤2) were analysed. Pearson correlation coefficients were calculated for all pairs of the four scales (HAM-D₁₇/MADRS, HAM-D₁₇/CGI-S, HAM-D₁₇/CGI-I, MADRS/CGI-S, MADRS/CGI-I, CGI-S/CGI-I) at different time points. Effect sizes were calculated using the Cohen d.

Results

Correlations were significant at all time points (p < 0.0001), increased over the course of treatment, and were similar across treatment groups. Effect sizes ranged from 0.31 to 0.42; MADRS and CGI-I effect sizes were slightly greater compared with HAM-D₁₇ or CGI-S for continuous measures and response.

Conclusion

Although MADRS and CGI-I were more sensitive to treatment effects, HAM-D₁₇, MADRS, CGI-S and CGI-I scores present a consistent picture of response to venlafaxine treatment.