title: Estimation of minimal clinically important difference in EQ-5D visual analog scale score after pulmonary rehabilitation in subjects with COPD.
abstract: BACKGROUND
  The effect of pulmonary rehabilitation (PR) on the EuroQol Group's 5-dimension questionnaire (EQ-5D) in COPD has been poorly investigated. In addition, conflicting results were reported about the visual analog scale component of EQ-5D (EQ-VAS). The purpose of this study was to evaluate the responsiveness of EQ-VAS to PR and its relationship with clinical and functional parameters in subjects with COPD, as well as to define the minimal clinically important difference (MCID) estimate for the EQ-VAS after PR.
  
  
  METHODS
  A total of 468 in-patients with stable moderate-to-severe COPD, allocated to a 3-wk PR program, were retrospectively evaluated. EQ-VAS was assessed before and after PR, and its relationship with baseline pulmonary function, changes in 6-min walk test, and baseline, and transitional dyspnea index (BDI/TDI) after PR were evaluated. Using an anchor-based approach and receiver operating characteristic curves, the EQ-VAS change cutoff that identified subjects achieving the known MCID for TDI after PR was identified.
  
  
  RESULTS
  Four hundred and thirty-nine subjects (94%, mean FEV1 55.3% predicted) completed pre- and post-PR EQ-VAS scores. After PR, EQ-VAS increased from 58 ± 17 to 72 ± 15 (ΔEQ-VAS 14 ± 12, P < .001). ΔEQ-VAS was negatively related to baseline FEV1 (r = -0.32, P < .001) and positively to TDI (r = 0.50, P < .001) and 6-min walk distance (r = 0.46, P < .001) changes. Receiver operating characteristic curves identified an EQ-VAS change cutoff of 8 as the best discriminating value to identify the MCID for TDI (0.78 sensitivity and 0.81 specificity; area under curve: 0.845, P < .001).
  
  
  CONCLUSIONS
  Our study shows that, in in-patients with stable moderate-to-severe COPD, EQ-VAS is a valid and reliable tool to assess the responsiveness to PR, with an estimated MCID of 8 points. The EQ-VAS can be a practical alternative to more time-consuming measures of health-related quality of life.
authors.affiliation: Division of Pneumology, Istituto di Ricovero e Cura a Carattere Scientifico Rehabilitation Institute of Tradate, Salvatore Maugeri Foundation, Tradate Department of Clinical and Experimental Medicine, University of Insubria, Varese andrea.zanini@fsm.it.
authors.forename: Andrea
authors.initials: A
authors.lastname: Zanini
authors.affiliation: Respiratory Disease and Lung Function Unit, Department of Clinical and Experimental Medicine, University of Parma, Parma, Italy.
authors.forename: Marina
authors.initials: M
authors.lastname: Aiello
authors.affiliation: Division of Pneumology, Istituto di Ricovero e Cura a Carattere Scientifico Rehabilitation Institute of Tradate, Salvatore Maugeri Foundation, Tradate.
authors.forename: Daniela
authors.initials: D
authors.lastname: Adamo
authors.affiliation: Division of Pneumology, Istituto di Ricovero e Cura a Carattere Scientifico Rehabilitation Institute of Tradate, Salvatore Maugeri Foundation, Tradate.
authors.forename: Silvia
authors.initials: S
authors.lastname: Casale
authors.affiliation: Division of Pneumology, Istituto di Ricovero e Cura a Carattere Scientifico Rehabilitation Institute of Tradate, Salvatore Maugeri Foundation, Tradate.
authors.forename: Francesca
authors.initials: F
authors.lastname: Cherubino
authors.affiliation: Division of Pneumology, Istituto di Ricovero e Cura a Carattere Scientifico Rehabilitation Institute of Tradate, Salvatore Maugeri Foundation, Tradate.
authors.forename: Sabrina
authors.initials: S
authors.lastname: Della Patrona
authors.affiliation: Division of Pneumology, Istituto di Ricovero e Cura a Carattere Scientifico Rehabilitation Institute of Tradate, Salvatore Maugeri Foundation, Tradate.
authors.forename: Eleonora
authors.initials: E
authors.lastname: Raimondi
authors.affiliation: Division of Pneumology, Istituto di Ricovero e Cura a Carattere Scientifico Rehabilitation Institute of Tradate, Salvatore Maugeri Foundation, Tradate.
authors.forename: Elisabetta
authors.initials: E
authors.lastname: Zampogna
authors.affiliation: Respiratory Disease and Lung Function Unit, Department of Clinical and Experimental Medicine, University of Parma, Parma, Italy.
authors.forename: Alfredo
authors.initials: A
authors.lastname: Chetta
authors.affiliation: Division of Pneumology, Istituto di Ricovero e Cura a Carattere Scientifico Rehabilitation Institute of Tradate, Salvatore Maugeri Foundation, Tradate Department of Clinical and Experimental Medicine, University of Insubria, Varese.
authors.forename: Antonio
authors.initials: A
authors.lastname: Spanevello
mesh_terms: D000368:Aged; D019540:Area Under Curve; D037001:Directive Counseling; D004417:Dyspnea / Q000209:etiology; D005080:Exercise Test; D005081:Exercise Therapy; D005260:Female; D005541:Forced Expiratory Volume; D006801:Humans; D008297:Male; D008875:Middle Aged; D010349:Patient Compliance; D010353:Patient Education as Topic; D029424:Pulmonary Disease, Chronic Obstructive / Q000150:complications / Q000503:physiopathology* / Q000534:rehabilitation*; D012372:ROC Curve; D012189:Retrospective Studies; D012720:Severity of Illness Index; D011795:Surveys and Questionnaires; D016138:Walking / Q000502:physiology
keywords: COPD; EuroQol; VAS; pulmonary rehabilitation