This poster was presented at the 31st annual Psych Congress, held Oct. 25-28, 2018, in Orlando, Florida.
Background: Patient Health Questionnaire-9 (PHQ-9) is a validated patient self-administrated tool of depression symptom severity. This study assessed the association between PHQ-9 severity and patient-centric outcomes among Major Depressive Disorder (MDD) patients.
Methods: Data were from the 2013 National Health and Wellness Survey (N=75,000), representative of US adults. Patients with clinician-diagnosed depression and PHQ-9 scores ≥10, or 0-9 and on 1 antidepressant were classified as MDD. Patients with PHQ-9 scores ≥15 receiving ≥2 concomitant antidepressants were classified as severe cases of treatment-resistant depression (TRD). PHQ-9 severity thresholds include: Minimal, 0-4; Mild, 5-9; Moderate, 10-14; Moderately-Severe, 15-19; and Severe, 20-27. Generalized linear models predicted health-related quality of life (HRQoL; SF-36) and productivity (Work Productivity and Activity Impairment questionnaire) outcomes by PHQ-9 severity and TRD status, controlling for covariates.
Results: This study included 6,997 MDD patients (60.8% female; 85.0% <65 years; 45.7% employed), of whom 344 were severe TRD (4.9%). Compared with minimal depression (M=47.00), SF-36 Mental Component Summary scores for mild, moderate, moderately-severe, and severe depression were 6.22, 11.59, 16.43, and 21.26 points lower, respectively; all p<0.001. Compared with minimal depression (M=47.82), SF-36 Physical Component Summary scores for mild, moderate, moderately-severe, and severe depression were 1.35, 2.22, 2.27, and 2.87 points lower, respectively; all p<0.001. The percentage of work impairment due to absenteeism and presenteeism among employed MDD patients was greater for mild (M=24.87%), moderate (M=32.60%), moderately-severe (M=39.56%), and severe depression (M=43.00%) versus minimal depression (M=16.02%); all p<0.001.
Conclusion: Depressive severity is associated with incremental reductions in HRQoL and work productivity.