title: Minimal clinically important differences for the EQ-5D and QWB-SA in Post-traumatic Stress Disorder (PTSD): results from a Doubly Randomized Preference Trial (DRPT).
abstract: OBJECTIVE
  To determine the minimal clinically important difference (MCID) for the health-utility measures EuroQol-5 dimensions (EQ-5D) and Quality of Well Being Self-Administered (QWB-SA) Scale in PTSD patients.
  
  
  METHODS
  Two hundred patients aged 18 to 65 years with PTSD enrolled in a doubly randomized preference trial (DRPT) examining the treatment and treatment-preference effects between cognitive behavioral therapy and pharmacotherapy with sertraline and completed the EQ-5D and QWB-SA at baseline and 10-week post-treatment. The anchor-based methods utilized a Clinical Global Impression-Improvement (CGI-I) and Clinical Global Impression-Severity. We regressed the changes in EQ-5D and QWB-SA scores on changes in the anchors using ordinary least squares regression. The slopes (beta coefficients) were the rates of change in the anchors as functions of change in EQ-5D and QWB, which represent our estimates of MCID. In addition, we performed receiver operating characteristic (ROC) curve analysis to examine the relationship between the changes in EQ-5D and QWB-SA scores and treatment-response status. The MCIDs were estimated from the ROC curve where they best discriminate between treatment responders and non-responders. The distribution-based methods used small to moderate effect size in terms of 0.2 and 0.5 of standard deviation of the pre-treatment EQ-5D and QWB-SA scores.
  
  
  RESULTS
  The anchor-based methods estimated the MCID ranges of 0.05 to 0.08 for the EQ-5D and 0.03 to 0.05 for the QWB. The MCID ranges were higher with the distribution-based methods, ranging from 0.04 to 0.10 for the EQ-5D and 0.02 to 0.05 for the QWB-SA.
  
  
  CONCLUSIONS
  The established MCID ranges of EQ-5D and QWB-SA can be a useful tool in assessing meaningful changes in patient's quality of life for researchers and clinicians, and assisting health-policy makers to make informing decision in mental health treatment.
  
  
  BACKGROUND
  Clinicaltrials.gov; Identifier: NCT00127673.
authors.affiliation: Department of Pharmacy Administration and Practice, Western University of Health Sciences, Pomona, CA 91766-1854, USA. qle@westernu.edu
authors.forename: Quang A
authors.initials: QA
authors.lastname: Le
authors.forename: Jason N
authors.initials: JN
authors.lastname: Doctor
authors.forename: Lori A
authors.initials: LA
authors.lastname: Zoellner
authors.forename: Norah C
authors.initials: NC
authors.lastname: Feeny
mesh_terms: D000293:Adolescent; D000328:Adult; D000368:Aged; D015928:Cognitive Behavioral Therapy; D004834:Epilepsy, Post-Traumatic / Q000188:drug therapy / Q000523:psychology*; D005260:Female; D006305:Health Status Indicators; D006801:Humans; D008297:Male; D008875:Middle Aged; D057240:Patient Preference; D011569:Psychiatric Status Rating Scales; D012372:ROC Curve; D012044:Regression Analysis; D012107:Research Design; D017367:Selective Serotonin Reuptake Inhibitors / Q000627:therapeutic use; D020280:Sertraline / Q000627:therapeutic use; D012720:Severity of Illness Index; D011795:Surveys and Questionnaires; D016896:Treatment Outcome
chemical_list: D017367:Selective Serotonin Reuptake Inhibitors; D020280:Sertraline