The relation between observer-rated depressive symptoms and patient-rated quality of life after six weeks of antidepressant treatment: pooled patient-level analysis of mirtazapine trials

Background The primary effect parameter in depression trials is usually a measure of depressive symptoms, e.g. the Hamilton Depression Rating Scale (HDRS). Such measures have been criticised for not covering patient-relevant domains, such as quality of life, and hence not accurately reflecting patient-experienced efficacy. Aims To investigate the relation between clinician-rated depressive symptoms and patient-reported quality of life measured by the Quality-of-Life Enjoyment and Satisfaction Questionnaire Short Form (Q-LES-Q-SF). Method We included data from six acute-phase trials ( n = 918) comparing mirtazapine to another antidepressant (amitriptyline, fluoxetine, paroxetine or venlafaxine) where both HDRS and Q-LES-Q-SF had been administered. No study included a placebo arm. Correlations between instruments (scales, subscales and items) were assessed after six weeks. Q-LES-Q-SF outcomes for participants who were in HDRS-defined remission were contrasted to those from participants with more severe depressive symptoms. Results Q-LES-Q-SF ratings correlated strongly with HDRS-17 ( r = −0.73, p < 0.0001) and HDRS-6 ( r = −0.72, p < 0.0001), but somewhat weaker to HDRS-11 ( r = −0.64, p < 0.0001). Depressed mood ( r = −0.66, p < 0.0001) and work and activities ( r = −0.65, p < 0.0001) showed the strongest item-level correlations to Q-LES-Q-SF. Participants in HDRS-remission had average Q-LES-Q-SF scores on the lower end of those reported by healthy controls, whereas patients with mild depressive symptoms (or worse) had average life-quality scores corresponding to severe impairment. Conclusions HDRS and Q-LES-Q-SF showed considerable agreement in depressed study participants treated with antidepressants, suggesting that HDRS meaningfully reflects patient-reported improvement.