Comparing five depression measures in depressed Chinese patients using item response theory: an examination of item properties, measurement precision and score comparability

Abstract

BackgroundItem response theory (IRT) has been increasingly applied to patient-reported outcome (PRO) measures. The purpose of this study is to apply IRT to examine item properties (discrimination and severity of depressive symptoms), measurement precision and score comparability across five depression measures, which is the first study of its kind in the Chinese context.MethodsA clinical sample of 207 Hong Kong Chinese outpatients was recruited. Data analyses were performed including classical item analysis, IRT concurrent calibration and IRT true score equating. The IRT assumptions of unidimensionality and local independence were tested respectively using confirmatory factor analysis and chi-square statistics. The IRT linking assumptions of construct similarity, equity and subgroup invariance were also tested. The graded response model was applied to concurrently calibrate all five depression measures in a single IRT run, resulting in the item parameter estimates of these measures being placed onto a single common metric. IRT true score equating was implemented to perform the outcome score linking and construct score concordances so as to link scores from one measure to corresponding scores on another measure for direct comparability.ResultsFindings suggested that (a) symptoms on depressed mood, suicidality and feeling of worthlessness served as the strongest discriminating indicators, and symptoms concerning suicidality, changes in appetite, depressed mood, feeling of worthlessness and psychomotor agitation or retardation reflected high levels of severity in the clinical sample. (b) The five depression measures contributed to various degrees of measurement precision at varied levels of depression. (c) After outcome score linking was performed across the five measures, the cut-off scores led to either consistent or discrepant diagnoses for depression.ConclusionsThe study provides additional evidence regarding the psychometric properties and clinical utility of the five depression measures, offers methodological contributions to the appropriate use of IRT in PRO measures, and helps elucidate cultural variation in depressive symptomatology. The approach of concurrently calibrating and linking multiple PRO measures can be applied to the assessment of PROs other than the depression context.

Evaluation of the Brazilian version of Patient Health Questionnaire (PHQ-9) in Quilombola population using the Item Response Theory

“…These results corroborate data about precarious health conditions of quilombola population (Gomes et al, 2013;Oliveira, Pereira, Guimarães, & Caldeira, 2015), the need to establish mental health policies that consider this vulnerability, and to consider the characteristics of the sample when assessing the psychometric qualities of the instruments (Meredith & Teresi, 2006). They also show the usefulness of using screening instruments to identify depressive symptoms in poor areas (Zhao et al, 2017).…”

“…In this study they observed a specificity ranging from .73, when adopting 7 as cut-off point, to .96, when adopting 15 as cut-off point. Other studies have also shown that the PHQ-9 has good discrimination capability for depressive disorders (Adler et al, 2012;Kendel et al, 2010;Zhao et al, 2017). Using this cut-off point, the PHQ-9 screened depression in a number of people twice higher than the depression prevalence estimated for the Brazilian general population (WHO, 2017).…”

“…depressive symptoms, have greater or lesser weight in the evaluation of levels of depression. The relevance of IRT analysis for depression screening scales has already been demonstrated (Adler et al, 2012;Zhao et al, 2017). Castro et al (2010), and Uher et al (2008) analyzed the BDI scale and pointed out the possibility of reducing the number of items and the need for recoding the answers according to their contribution for understanding depression.…”

“…The IRT has been widely used to assess the adequacy of instruments in the field of mental health (Adler et al, 2012). Zhao, Chan, & Lo (2017) examined five scales for depression screening in China showing that the scale has great potential to identify moderate to severe depression. Forkmann, Gauggel, Spangenberg, Brähler, & Glaesmer (2013) examined the German version of the PHQ-9 and shows the scale has psychometric problems.…”

Longitudinal invariance and information of the Depression, Anxiety, and Stress Scales

“…These studies do not, however, discuss the instrument's information in different score categories. More recently, Zhao, Chan, and Lo (2017) found that the Depression subscale is sufficiently informative only in the moderate and extremely severe categories.…”