title: Responsiveness and Minimal Important Changes of the Western Ontario and McMaster Universities Osteoarthritis Index in Subjects Undergoing Rehabilitation Following Hip Fracture.
abstract: OBJECTIVE
  To evaluate the responsiveness and minimal important changes (MICs) for the Western Ontario and McMaster Universities Osteoarthritis Index (WOMAC) and its subscales in subjects with hip fractures.
  
  
  METHODS
  At the beginning and end of a 2-month rehabilitation program, 106 patients completed the WOMAC. After the program, the global perceived effect (GPE) was analyzed to produce a dichotomous outcome (improved vs. stable). Responsiveness for the WOMAC and its subscales were calculated by distribution (effect size; standardized response mean) and anchor-based methods (receiver operating characteristic curves; correlations between change scores of the WOMAC and its subscales and GPE). Receiver operating characteristic curves were also used in order to compute the best cutoff levels between improved and stable subjects (MICs).
  
  
  RESULTS
  The effect size ranged from 0.64 to 11.10 and the standardized response mean from 0.79 to 2.65. The receiver operating characteristic analyses revealed an MIC value (area under the curve, sensitivity, specificity) for the WOMAC of 29 (0.817, 92, 78); values of 35 (0.820, 77, 76) 44 (0.625, 25, 95), and 24 (0.707, 100, 76) were found for pain, stiffness, and physical function subscales, respectively. Correlations between change scores of the WOMAC and its subscales and GPE were low (0.240, for stiffness subscale) to moderate (0.438-0.570 for the other subscales and the WOMAC).
  
  
  CONCLUSIONS
  The WOMAC and its subscales (all but stiffness) were sensitive in detecting clinical changes in subjects with hip fracture undergoing rehabilitation. We recommend taking the MICs provided into account when assessing patients' improvement or planning studies in this clinical context.
authors: From the Department of Public Health, Clinical and Molecular Medicine, University of Cagliari, Cagliari (MM); Physical Medicine and Rehabilitation Unit, Scientific Institute of Lissone, Salvatore Maugeri Foundation, Institute of Care and Research (IRCCS), Lissone (MM, EA, BR); Neuroengineering and Medical Robotics Laboratory, Department of Electronics, Information and Bioengineering, Politecnico di Milano, Milan (EA, SF); and Physical Medicine and Rehabilitation School (CS) and Orthopaedic Unit, Department of Surgery (AC), University of Cagliari, Cagliari, Italy.
authors: Marco
authors: M
authors: Monticone
authors: Emilia
authors: E
authors: Ambrosini
authors: Claudio
authors: C
authors: Secci
authors: Barbara
authors: B
authors: Rocca
authors: Simona
authors: S
authors: Ferrante
authors: Antonio
authors: A
authors: Capone
mesh_terms: D000368:Aged; D004185:Disability Evaluation; D005260:Female; D006620:Hip Fractures / Q000503:physiopathology / Q000534:rehabilitation* / Q000601:surgery; D006801:Humans; D008297:Male; D000071066:Patient Reported Outcome Measures; D026741:Physical Therapy Modalities; D012372:ROC Curve