Economic outcomes of eszopiclone treatment in insomnia and comorbid major depressive disorder

Abstract

Background: Eszopiclone is effective for the treatment of insomnia in patients with insomnia and comorbid major depressive disorder (MDD). Both conditions impose significant economic burden, with the US societal cost of depression estimated at USD 50 billion annually.

Aims of the study: The purpose of this analysis was to examine the costs and benefits of eszopiclone co-administered with fluoxetine (ESZ+FLX) compared to placebo co-administered with fluoxetine (PBO+FLX) in adults meeting the DSM-IV criteria for insomnia and MDD.

Methods: Data from 434 patients enrolled in an 8-week clinical trial who met the economic-subanalysis criteria were examined. The costs of medical care (in 2007 USUSD ) and lost work time were estimated from the Hamilton Depression Scale (HAM-D17) scores using published algorithms. Cost of lost productivity while at work was based on responses to the Work Limitations Questionnaire. The impact of therapy on quality-adjusted life years (QALYs) was estimated by transforming HAM-D17 (base case analysis) or Short Form Health Survey (SF-12) (scenario analyses) responses into health utility scores using published algorithms. Drug costs were estimated based on average wholesale price.

Results: The mean 8-week increases in QALYs from baseline were 0.0392 and 0.0334 for the ESZ+FLX and PBO+FLX groups, respectively. Mean per-patient costs were USD 1,279 and USD 1,198 for the respective groups. Thus, co-treatment resulted in net increases of 0.0058 QALYs and USD 81, leading to an incremental cost per QALY gained of approximately USD 14,000.

Discussion and limitations: Co-administration of eszopiclone and fluoxetine improved patients' insomnia symptoms and appeared to be a cost-effective treatment strategy for patients with insomnia and comorbid MDD. One limitation of this study is that optimal utility estimation techniques were not available. Utilities were instead derived indirectly using the HAM-D17 (disease-specific, not generic) or SF-12 (generic, but potentially insensitive to important changes in some conditions) instruments.

Implications for health care provision: Sleep disturbance is predictive of depression relapse, and is the most common residual symptom in patients who have been successfully treated with fluoxetine for depression. Thus, identifying cost-effective strategies for the treatment of insomnia symptoms is important for this patient population.

Implications for health policies: Treatment guidelines and drug coverage decisions should be based on clinical evidence, effectiveness, and economic criteria (i.e., whether an effective drug therapy produces sufficient benefits given its costs). This information about the overall value of eszopiclone can be measured as the cost per QALY gained with the use of ESZ+FLX compared with FLX alone. In order to make decisions based on value, payers and policy makers must have access to reliable cost-effectiveness information.

Implications for further research: The residual efficacy observed in the clinical trial following the discontinuation of co-therapy should be explored further to determine whether intermittent treatment with ESZ+FLX is a cost-effective strategy.