Health-related quality of life burden associated with treatment-resistant depression in UK patients: Quantitative results from a mixed-methods non-interventional study

Background: Major depressive disorder (MDD) and its more intractable variant, treatment-resistant depression (TRD), are common conditions that adversely affect patient well-being and health-related quality of life (HRQoL). This study aimed to quantify the impact of MDD and particularly TRD on the HRQoL, functioning and productivity of UK patients to support clinical and reimbursement decisions and policymaking. Methods: 148 patients with clinician-verified symptomatic (non-treatment-resistant) MDD (Patients-MDD; n = 61) or TRD (Patients-TRD; n = 87) were recruited from ten clinical sites. Participants completed validated patient-reported outcome measures assessing depressive symptom severity (Patient Health Questionnaire-9 [PHQ-9]), HRQoL (EQ-5D-5 L/abbreviated World Health Organization Quality of Life Questionnaire [WHOQOL-BREF]) and work productivity/activity impairment (WPAI:D). Results: Patients-TRD and Patients-MDD reported similar levels of depressive symptom severity (mean PHQ-9 16.2/16.6, respectively). However, HRQoL was significantly poorer for Patients-TRD compared with Patients-MDD, both in the overall cohort (median EQ-5D-5 L utility 0.606/0.721, respectively [p = 0.021]; WHOQOL-BREF overall score 55.2/58.8 [p = 0.024]) and in patients with a PHQ-9 score >= 15 (median EQ-5D-5 L utility 0.415/0.705, respectively [p<0.001]). Although a numerically lower proportion of Patients-TRD were employed (45% vs 57% of Patients-MDD; p = 0.204), employed Patients-MDD reported significantly higher absenteeism and work productivity loss. Limitations: A minority of patients screened as having symptomatic MDD or TRD self-reported low PHQ-9 symptom severity. This was addressed with a subgroup analysis of patients with more severe depression. Conclusions: TRD is associated with an added patient HRQoL burden, above that observed for non-treatment-resistant MDD. This highlights the unmet need for greater access to improved treatment, including new treatment options for Patients-TRD.