What factors indicate prognosis for adults with depression in primary care? A protocol for meta-analyses of individual patient data using the Dep-GP database

Joshua E.J Buckman,Simon Gilbody,Edward Watkins,Gareth Ambler,Tony Kendrick,Glyn Lewis,Ian R White,Robert J Derubeis,Zachary D Cohen,Stephen Pilling,Steven D Hollon,Katherine Clarke,Rob Saunders

doi:10.12688/wellcomeopenres.15225.1

Abstract

Background: Pre-treatment severity is a key indicator of prognosis for those with depression. Knowledge is limited on how best to encompass severity of disorders. A number of non-severity related factors such as social support and life events are also indicators of prognosis. It is not clear whether this holds true after adjusting for pre-treatment severity as a) a depressive symptom scale score, and b) a broader construct encompassing symptom severity and related indicators: "disorder severity". In order to investigate this, data from the individual participants of clinical trials which have measured a breadth of "disorder severity" related factors are needed. Aims: 1) To assess the association between outcomes for adults seeking treatment for depression and the severity of depression pre-treatment, considered both as i) depressive symptom severity only and ii) "disorder severity" which includes depressive symptom severity and comorbid anxiety, chronicity, history of depression, history of previous treatment, functional impairment and health-related quality of life. 2) To determine whether i) social support, ii) life events, iii) alcohol misuse, and iv) demographic factors (sex, age, ethnicity, marital status, employment status, level of educational attainment, and financial wellbeing) are prognostic indicators of outcomes, independent of baseline "disorder severity" and the type of treatment received. Methods: Databases were searched for randomised clinical trials (RCTs) that recruited adults seeking treatment for depression from their general practitioners and used the same diagnostic and screening instrument to measure severity at baseline - the Revised Clinical Interview Schedule; outcome measures could differ between studies. Chief investigators of all studies meeting inclusion criteria were contacted and individual patient data (IPD) were requested. Conclusions: In total 13 RCTs were found to meet inclusion criteria. The Dep-GP database was formed from the 6271 participants. This protocol outlines how these data will be analysed. Registration: PROSPERO CRD42019129512 (01/04/2019).

Highlights

One in 20 adults across the globe will experience an episode of major depression every year (Thornicroft et al, 2017), most of whom will not receive any treatment (Olfson et al, 2016; Thornicroft et al, 2017)
Knowledge of prognosis for those seeking treatment for depression after accounting for baseline severity has been limited to the consideration of severity only as a depressive symptom scale score, but many other related factors including the chronicity of depression and comorbid symptoms of anxiety have been found to be important prognostic indicators
A number of factors have been reported to be indicators of prognosis for depressed patients, but whether this is true after adjusting for severity encompassed in a scale score or a more broad range of related factors remains to be seen

Summary

Introduction

One in 20 adults across the globe will experience an episode of major depression every year (Thornicroft et al, 2017), most of whom will not receive any treatment (Olfson et al, 2016; Thornicroft et al, 2017). Aims and objectives 1) To determine whether certain “disorder severity” factors are indicators of prognosis, independent of treatment, and independent of baseline depression symptom scale scores These are i) chronicity of depression at baseline; ii) a history of depression; iii) a history of any previous treatment for depression; iv) a history of ADM treatment; v) anxiety symptom severity; vi) presence of and number of comorbid anxiety disorders; vii) duration of anxiety problems; viii) functional impairment; and ix) health-related quality of life. 2) To determine whether or not the following are indicators of prognosis independent of severity of depression as measured in both ways outlined in 1 above - symptom severity, and “disorder severity”: i) social support ii) the occurrence of recent stressful life events iii) alcohol misuse iv) d emographic factors (age, gender, ethnicity, employment status, marital status, highest level of educational attainment, and financial wellbeing including housing status)

Methods

Total score on the alcohol measure

Findings

Discussion and conclusions