Understanding the Relationship Between Depression Symptom Severity and Health Care Costs for Patients With Treatment-Resistant Depression.

Objective: To examine whether measures of depression symptom severity could improve understanding of health care costs for patients with major depressive disorder (MDD) or treatment-resistant depression (TRD) from the health plan perspective.Methods: In this retrospective cohort study within an integrated health system, cohorts consisted of 2 mutually exclusive groups: (1) adults with TRD based on a standard treatment algorithm and (2) adults with MDD, but no TRD, identified through ICD-9/10-CM codes. Depression severity was measured using the Patient Health Questionnaire-9 (PHQ-9). Patterns of health care resource utilization (HRU) and costs were compared between the TRD and MDD groups overall and within the groups at different symptom levels. A general linear model with a γ distribution and log link for cost outcomes, logistic regression for binary outcomes, and negative binomial regression for count outcomes were used.Results: Patients with TRD (n = 24,534) had greater comorbidity than those in the MDD group (n = 17,628). Mean age in the TRD group was 52.8 years versus 48.2 for MDD (P < .001). Both groups were predominantly female (TRD: 72.8% vs MDD: 66.9%; P < .001). Overall, the TRD group had greater costs than the MDD group, with 1.23 times (95% CI, 1.21-1.26; P < .001) greater total cost on average over 1 year following index date. Within both groups, those with severe symptoms had greater total mean (SD) costs (TRD: moderate: $12,429 [$23,900] vs severe: $13,344 [$22,895], P < .001; low: $12,220 [$31,864] vs severe: $13,344 [$22,895], P < .001; MDD: moderate: $8,899 [$20,755] vs severe: $10,098 [$22,853]; P < .001; low: $8,752 [$25,800] vs severe: $10,098 [$22,853], P < .001).Conclusions: MDD and TRD impose high costs for health systems, with increasing costs as PHQ-9 symptom severity rises. Better understanding of subgroups with different symptom levels could improve clinical care by helping target interventions.

Cost-Effectiveness of Repetitive Transcranial Magnetic Stimulation versus Antidepressant Therapy for Treatment-Resistant Depression.

BACKGROUND: Repetitive transcranial magnetic stimulation (rTMS) therapy is a clinically safe, noninvasive, nonsystemic treatment for major depressive disorder. OBJECTIVE: We evaluated the cost-effectiveness of rTMS versus pharmacotherapy for the treatment of patients with major depressive disorder who have failed at least two adequate courses of antidepressant medications. METHODS: A 3-year Markov microsimulation model with 2-monthly cycles was used to compare the costs and quality-adjusted life-years (QALYs) of rTMS and a mix of antidepressant medications (including selective serotonin reuptake inhibitors, serotonin and norepinephrine reuptake inhibitors, tricyclics, noradrenergic and specific serotonergic antidepressants, and monoamine oxidase inhibitors). The model synthesized data sourced from published literature, national cost reports, and expert opinions. Incremental cost-utility ratios were calculated, and uncertainty of the results was assessed using univariate and multivariate probabilistic sensitivity analyses. RESULTS: Compared with pharmacotherapy, rTMS is a dominant/cost-effective alternative for patients with treatment-resistant depressive disorder. The model predicted that QALYs gained with rTMS were higher than those gained with antidepressant medications (1.25 vs. 1.18 QALYs) while costs were slightly less (AU $31,003 vs. AU $31,190). In the Australian context, at the willingness-to-pay threshold of AU $50,000 per QALY gain, the probability that rTMS was cost-effective was 73%. Sensitivity analyses confirmed the superiority of rTMS in terms of value for money compared with antidepressant medications. CONCLUSIONS: Although both pharmacotherapy and rTMS are clinically effective treatments for major depressive disorder, rTMS is shown to outperform antidepressants in terms of cost-effectiveness for patients who have failed at least two adequate courses of antidepressant medications.