Direct and indirect costs of employees with treatment-resistant and non-treatment-resistant major depressive disorder

Abstract

Treatment-resistant depression (TRD) imposes substantial cost from the perspective of employers. The objective of this study was to assess direct healthcare costs and indirect (disability and medical-related absenteeism) costs associated with TRD compared with non-treatment-resistant major depressive disorder (MDD). Employees with one or more inpatient, or two or more outpatient/other MDD diagnoses (ICD-9-CM: 296.2x, 296.3x) from 2004 through 2007, ages 18–63 years, were selected from a claims database. Employees who initiated a third antidepressant following two antidepressant treatments of adequate dose and duration or who met published TRD criteria were classified as TRD likely (N = 2312). The index date was the date of the first antidepressant, starting 1/1/2004. The control group was an age- and sex-matched cohort of employees with MDD but without TRD. All had continuous eligibility during the 6-month pre-index (baseline) and 24-month post-index (study) period. McNemar tests were used to compare baseline comorbidities. Wilcoxon signed-rank tests were used to compare costs from employer perspective. TRD-likely employees were on average 48 years old, and 64.8% were women. Compared with MDD controls, TRD-likely employees had significantly higher rates of mental-health disorders, chronic pain, fibromyalgia, and higher Charlson Comorbidity Index. Average direct 2-year costs were significantly higher for TRD-likely employees ($22,784) compared with MDD controls ($11,733), p < 0.0001. Average indirect costs were also higher among TRD-likely employees ($12,765) compared with MDD controls ($6885), p < 0.0001. Limitations of claims data related to accuracy of diagnosis coding and lack of clinical information apply to this study. Based on comorbidities and healthcare resources used, patients with TRD appeared to represent a clinically complex subgroup of individuals with MDD. TRD was associated with significant cost burden.