The Relationship Between Quality of Life and Clinical Efficacy From a Randomized Trial Comparing Olanzapine and Ziprasidone

Glenn A. Phillips, Ph.D.; David L. Van Brunt, Ph.D.; Suraja M. Roychowdhury, Ph.D.; Wen Xu, Ph.D.; and Dieter Naber, M.D.

Objective: To examine treatment-specific changes in health-related quality of life (QOL) among patients with schizophrenia and to assess the association between clinical and QOL improvement.

Method: This post hoc analysis used the findings of a 28-week, randomized, multicenter trial of patients with schizophrenia (DSM-IV) treated with olanzapine (10-20 mg/day) or ziprasidone (80-160 mg/day). Data were collected from August 2001 to December 2002. Efficacy was measured using the Positive and Negative Syndrome Scale (PANSS). Quality of life was assessed with the generic health self-administered Medical Outcomes Study Short-Form 36-Item Health Survey (SF-36) and the disease-specific expert-administered Heinrichs-Carpenter Quality of Life Scale (QLS). Mixed-effects-repeated-measures and last-observation-carried-forward approaches were used to assess the effects of treatment on QOL and the association of clinical outcomes to QOL outcomes.

Results: Olanzapine- and ziprasidone-treated patients demonstrated similar improvement from baseline to endpoint on the SF-36 and QLS. All correlations between changes in PANSS scores and the SF-36 were significant (p < .001), ranging from -0.159 to -0.400. All correlations between changes in PANSS scores and the QLS were significant (p < .0001), ranging from -0.286 to -0.603. The correlations between the 2 QOL measures were generally significant but small to moderate in magnitude.

Conclusions: The results of this study indicate that, in patients with schizophrenia, olanzapine and ziprasidone treatment are associated with significant QOL and clinical improvements. Further, the significant correlation between change scores on the PANSS and QOL measures suggests that treatment-related clinical improvements are associated with improved health-related and disease-specific QOL.

Clinical Trials Registration: ClinicalStudyResults.org identifier 2347.

(J Clin Psychiatry 2006;67:1397-1403)

Received Feb. 24, 2005; accepted Feb. 2, 2006. From Eli Lilly and Company, Indianapolis, Ind. (Drs. Phillips, Van Brunt, Roychowdhury and Xu); and the Department of Psychiatry, University of Hamburg, Hamburg, Germany (Dr. Naber). Dr Roychowdhury is now with GlaxoSmithKline, Research Triangle Park, N.C.

This study was funded by Eli Lilly and Company, Indianapolis, Ind.

Drs. Phillips, Van Brunt, and Xu are employees of Eli Lilly. Dr. Roychowdhury was an employee of Eli Lilly until May 2005. Dr. Naber reports no additional financial or other relationships relevant to the subject of this article.

Corresponding author and reprints: Glenn A. Phillips, Ph.D., Lilly Corporate Center, Drop Code 4133, Indianapolis, IN 46285 (e-mail: phillipsga@lilly.com).