ECONOMIC EVALUATIONS OF GENERALIZED ANXIETY DISORDER: A SYSTEMATIC LITERATURE REVIEW

Purpose: To review the literature reporting economic outcomes of patients with generalized anxiety disorder (GAD) and to highlight the impact of resource utilization and management of this disorder to decision-making stakeholders.

 Methods: Acceptability criteria included: full economic evaluations (cost-benefit, cost-minimization, cost-effectiveness, cost-utility analysis), partial economic evaluations (cost-of-illness or resource utilization studies), and humanistic studies (utilities, preferences, and willingness to pay). GAD diagnosis per the International Classification of Diseases (ICD) or the Diagnostic and Statistical Manual of Mental Disorders (DSM) was required for inclusion. Embase, EBM Reviews, Medline, and Healthstar were searched for relevant articles. A manual search of references from included studies was performed. Study parameters and outcomes were extracted. Reporting quality was assessed using the Neumann et al. checklist.

 Results: Thirty-eight articles were included for review: 26 studies used DSM-IV or DSM-III-R criteria, 2 used DSM-III (shorter time-horizon requirement). Eight studies used ICD criteria (7 using ICD-10; 1 using ICD-9 version). Four full economic evaluations were included; Incremental cost of current over “optimal care” was $2,713 per years lived with disability; £380/per successfully treated venlafaxine-XR patient; £1408 cost-savings of escitalopram over paroxetine; $6,900 saved per disability adjusted life year of public salary psychologist compared to current practice.  Outcomes were based on conventional decision-making modeling or population summary data (time-horizons 12 months or less). The mean reporting quality was 4.7 (SD=0.71, max=7). Most studies reported that GAD patients (with/without co-morbidities) were more likely to use primary care than patients with other psychiatric disorders. Impairment in patients with GAD alone is equivalent to those with mood disorders alone and greater than those with other anxiety or personality disorders. Patients with co-morbid GAD (e.g., major depression episodes) have a higher degree of disability than patients with ‘pure’ GAD or ‘pure’ mood disorders and experience significantly higher absenteeism than patients with GAD alone. GAD co-morbidity resulted in reduced utility and quality of life scores compared to patients with ‘pure’ GAD. GAD patients have lower quality of physical and mental health as well as satisfaction levels than the general population  

 Conclusion: GAD incurs a significant impact on resource utilization, impairment, and quality of life. Although full and partial economic evaluations of GAD patients have been reported, no studies assessing consequences reflecting the chronic nature of the disorder were located.