HEALTH-RELATED QUALITY OF LIFE IN REMITTED PSYCHOTIC DEPRESSION

Abstract

Introduction Health-Related Quality of Life (HRQL) (defined as a person's perceived life functioning and wellbeing in the physical, mental and social domains of health) is recognized as an important outcome to consider in healthcare delivery, research, and policy. Patients with depression report more impaired HRQL than population norms and with impairment persisting in some patient groups despite clinical remission. Psychotic depression is a severe disorder associated with significant disability and poor HRQL during acute episodes. No studies have investigated HRQL in remitted psychotic depression, and it is therefore not known to what extent impairment of HRQL persists into sustained remission in this group. The primary aim of this study is to examine HRQL in both acute and remitted psychotic depression and to compare it to age- and gender-adjusted population norms. In addition, exploratory aims are to examine i) the relation of age group to HRQL and change in HRQL from baseline to remission, and ii) the association of depression scores, medical burden, and neuropsychological function in remission with HRQL. Methods This study is a secondary analysis of the Sustaining Remission of Psychotic Depression (STOP-PD II) dataset. STOP-PD II is a randomized, placebo-controlled trial investigating the benefits and risks of continuing antipsychotic medication in persons between 18 and 85 years of age with psychotic depression that had remitted with the combination of sertraline and olanzapine. STOP-PD II has 3 phases: acute, stabilization, and randomized. This analysis includes only participants who experienced sustained remission of both depression and psychosis by the end of the stabilization phase (n = 119). Our primary outcome of HRQL was measured using the Medical Outcome Survey Short Form (SF-36)—a tool that contains eight scales reflecting physical, emotional and social domains of subjective health status—administered at baseline (entry to the study) and at the end of the stabilization phase. Paired t-tests were used to compare SF-36 scores between baseline and remission. To compare SF-36 scores in STOP-PD II participants with those of the general American population adjusting for age group and gender, SF-36 scores were standardized to z-scores for each age/gender stratum provided in the SF-36 manual. We examined the z-scores descriptively via means, standard errors and confidence intervals using the normative population mean of zero as a point of reference. We also compared the SF-36 scores of younger (18-59 years) and older (60 years or older) participants. Independent t-tests compared in these age groups: i) SF-36 scores at baseline and remission, and ii) the magnitude of change in SF-36 scores between baseline and remission. Finally, we explored the relationship between SF-36 scores and depression scores, medical burden, and neuropsychological performance at remission using correlation analyses. Results SF-36 scores improved significantly from baseline to remission for all scales. As expected, improvement from baseline to remission was largest for the mental health-related scales, and smallest for scales related to medical health. At baseline, all of the SF-36 z-scores except Bodily Pain were significantly lower than the population mean of zero, with Mental Health and Social Functioning scores approximately two standard deviations lower (see Table 1). By contrast, at remission, standardized SF-36 scores were very close to the population mean, with most of the confidence intervals including zero (see Table 1). Of the SF-36 scale scores at baseline or remission, only physical functioning was significantly different between age groups (baseline t= -3.12, df = 116, p = 0.0023; remission t = -2.73, df = 111, p = 0.0074). None of the change scores differed significantly between age groups. In remission, depression scores were moderately correlated with SF-36 scales (r ranging from 0.37-0.53) with the exception of bodily pain; medical burden and trail making scores were moderately correlated with SF-36 scales measuring physical symptoms (r ranging from 0.3 -0.52). The neuropsychological measures of coding and delayed recall had very weak correlations with the SF-36 scale scores in remission (r ranging from -0.09 - 0.19). Conclusions This study is the first to investigate HRQL in remitted psychotic depression. Participants with psychotic depression in sustained remission demonstrated similar levels of HRQL to population norms, regardless of age group, despite marked impairment on most HRQL domains when acutely ill. This finding is encouraging, as it suggests that, when treated in a rigorous and systematic manner, many patients with this severe illness improve significantly from both a clinical and HRQL perspective. Nevertheless, even in a sustained remitted state, low levels of depressive symptoms still influence HRQL. This research was funded by This secondary analysis did not receive any funding. The STOP-PD clinical trial was funded by USPHS grants MH 62446, MH 62518, MH 62565, and MH 62624 from the National Institute of Mental Health. Eli Lilly did not provide funding for this study but provided olanzapine and matching placebo pills; Pfizer did not provide funding for this study but provided sertraline.