title: Validation of the Chinese version of the PHQ-15 in a tertiary hospital.
abstract: BACKGROUND
  This study aimed to investigate the reliability and validity of the Chinese version of the Patient Health Questionnaire (PHQ-15) in a tertiary hospital.
  
  
  METHODS
  Using a cross-sectional study design, the Chinese version of the PHQ-15 was administered to a total of 1329 inpatients. To examine the discriminant validity of this questionnaire, we investigated the correlation of the PHQ-15 score with sociodemographic data and the PHQ-9 and GAD-7 scale scores. Exploratory factor analysis was performed to assess the internal consistency of the PHQ-15. To evaluate the consistency of this questionnaire with item response theory (IRT), IRT analysis was performed.
  
  
  RESULTS
  The Chinese version of the PHQ-15 showed good reliability (Cronbach's alpha = 0.83). The correlations of the PHQ-15 scores with the PHQ-9 depression scale scores (r = 0.565) and the GAD-7 anxiety scale scores (r = 0.512) were moderate; these results suggested that the PHQ-15 had discriminant validity. We identified three factors, referred to as "cardiopulmonary," "gastrointestinal," and "pain/neurological," which explained 56 % of the total variance. A second-order factor analysis including these three factors produced an acceptable model. Several items (4, 8 and 11) displayed extreme floor effects. Additionally, item 4 displayed a very small variance of 0.35 and showed very small differences in its thresholds based on IRT analysis.
  
  
  CONCLUSIONS
  The PHQ-15 scale had good reliability and high validity to detect patients with high somatic symptom severity in a Chinese tertiary hospital. Several of the current findings were consistent with previous research on the PHQ-15 in Western countries and in China. To improve the diagnostic quality of this questionnaire, items 4, 8 and 11 can be omitted.
authors.affiliation: Mental Health Center, West China Hospital of Sichuan University, No. 28 Dianxin S. St., Chengdu, Sichuan, 610041, P. R. China.
authors.forename: Lan
authors.initials: L
authors.lastname: Zhang
authors.affiliation: Department of Psychosomatic Medicine and Psychotherapy, University Medical Centre Freiburg, Hauptstr. 8, D-79104, Freiburg, Germany. kurt.fritzsche@uniklinik-freiburg.de.
authors.forename: Kurt
authors.initials: K
authors.lastname: Fritzsche
authors.affiliation: Mental Health Center, West China Hospital of Sichuan University, No. 28 Dianxin S. St., Chengdu, Sichuan, 610041, P. R. China.
authors.forename: Yang
authors.initials: Y
authors.lastname: Liu
authors.affiliation: Mental Health Center, West China Hospital of Sichuan University, No. 28 Dianxin S. St., Chengdu, Sichuan, 610041, P. R. China.
authors.forename: Jian
authors.initials: J
authors.lastname: Wang
authors.affiliation: Mental Health Center, West China Hospital of Sichuan University, No. 28 Dianxin S. St., Chengdu, Sichuan, 610041, P. R. China.
authors.forename: Mingjin
authors.initials: M
authors.lastname: Huang
authors.affiliation: Mental Health Center, West China Hospital of Sichuan University, No. 28 Dianxin S. St., Chengdu, Sichuan, 610041, P. R. China.
authors.forename: Yu
authors.initials: Y
authors.lastname: Wang
authors.affiliation: Mental Health Center, West China Hospital of Sichuan University, No. 28 Dianxin S. St., Chengdu, Sichuan, 610041, P. R. China.
authors.forename: Liang
authors.initials: L
authors.lastname: Chen
authors.affiliation: Mental Health Center, West China Hospital of Sichuan University, No. 28 Dianxin S. St., Chengdu, Sichuan, 610041, P. R. China.
authors.forename: Shanxia
authors.initials: S
authors.lastname: Luo
authors.affiliation: Mental Health Center, West China Hospital of Sichuan University, No. 28 Dianxin S. St., Chengdu, Sichuan, 610041, P. R. China.
authors.forename: Jianying
authors.initials: J
authors.lastname: Yu
authors.affiliation: Mental Health Center, West China Hospital of Sichuan University, No. 28 Dianxin S. St., Chengdu, Sichuan, 610041, P. R. China.
authors.forename: Zaiquan
authors.initials: Z
authors.lastname: Dong
authors.affiliation: Mental Health Center, West China Hospital of Sichuan University, No. 28 Dianxin S. St., Chengdu, Sichuan, 610041, P. R. China.
authors.forename: Liling
authors.initials: L
authors.lastname: Mo
authors.affiliation: Institute of Psychology, University of Freiburg, Freiburg, Germany.
authors.forename: Rainer
authors.initials: R
authors.lastname: Leonhart
mesh_terms: D002681:China; D003430:Cross-Sectional Studies; D005163:Factor Analysis, Statistical; D005260:Female; D006304:Health Status; D006801:Humans; D007802:Language; D008297:Male; D008875:Middle Aged; D011569:Psychiatric Status Rating Scales; D011594:Psychometrics / Q000706:statistics & numerical data; D015203:Reproducibility of Results; D011795:Surveys and Questionnaires / Q000592:standards*; D062606:Tertiary Care Centers; D014175:Translating
keywords: China; Item response theory analysis; Patient Health Questionnaire (PHQ-15); Somatic symptoms; Validation