title: Outcomes after total hip replacement based on patients' baseline status: what results can be expected?
abstract: OBJECTIVE
  We evaluated patient satisfaction with total hip replacement (THR) to establish cut points of sufficient improvement based on the patient acceptable symptom state (PASS) and receiver operating characteristic (ROC) curves, and compared them with measures derived from the minimum clinically important difference (MCID), taking into account patients' baseline status.
  
  
  METHODS
  Two cohorts of prospectively recruited patients on waiting lists for THR were studied. Sociodemographic data and comorbidities were recorded. Patients completed the Western Ontario and McMaster Universities Osteoarthritis Index (WOMAC) and other patient-reported outcomes questionnaires before THR and 6 months afterward. Cut points of sufficient improvement were established by the PASS, ROC, and MCID and were compared.
  
  
  RESULTS
  Patients satisfied with THR had, by preintervention WOMAC tertiles, gains of 19.4, 34.1, and 49.3 in the WOMAC pain domain and 17.8, 30.8, and 41.4 in the WOMAC functional limitation domain. The PASS cut points determined were 20, 25, and 25 for postintervention WOMAC pain and 28, 35, and 42 for functional limitation. ROC cut points were 19, 25, and 25 for postintervention pain and 26.4, 39, and 40 for functional limitation. Agreement among cut points classifying patients as responders to THR was 1.0 for pain with both PASS and ROC, and 0.85 for functional limitation; 0.6 for pain between MCID and PASS or ROC, and 0.58 and 0.60 for functional limitation.
  
  
  CONCLUSIONS
  Cut points of expected gain after THR can help clinicians, researchers, and managers to identify suitable candidates for THR, although such measures must be used with caution.
authors.affiliation: Unidad de Investigacion, Hospital Galdakao-Usansolo, CIBER Epidemiología y Salud Pública, Galdakao, Vizcaya, Spain. josemaria.quintanalopez@osakidetza.net
authors.forename: Jose M
authors.initials: JM
authors.lastname: Quintana
authors.forename: Urko
authors.initials: U
authors.lastname: Aguirre
authors.forename: Irantzu
authors.initials: I
authors.lastname: Barrio
authors.forename: Miren
authors.initials: M
authors.lastname: Orive
authors.forename: Susana
authors.initials: S
authors.lastname: Garcia
authors.forename: Antonio
authors.initials: A
authors.lastname: Escobar
mesh_terms: D000368:Aged; D019644:Arthroplasty, Replacement, Hip; D015331:Cohort Studies; D005260:Female; D006306:Health Surveys; D006801:Humans; D008297:Male; D015207:Osteoarthritis, Hip / Q000601:surgery*; D017060:Patient Satisfaction; D011446:Prospective Studies; D012189:Retrospective Studies; D057566:Self Report; D011795:Surveys and Questionnaires; D016896:Treatment Outcome