title: Assessment of patient functional status after surgery.
abstract: BACKGROUND
  Improvement in day-to-day functioning is a valued outcome of surgical intervention. A new functional status assessment instrument, the Activities Assessment Scale (AAS), was designed for a randomized clinical trial evaluating laparoscopic versus open hernia repair procedures.
  
  
  METHODS
  The study data set included 2,164 patients at baseline and 1,562 patients at 3-month followup. Only male patients were enrolled in the trial. The psychometric characteristics of the AAS were examined in statistical analyses of cross-sectional and longitudinal data from the trial. Correlational analyses, factor analyses, and t-tests were used to evaluate scale performance.
  
  
  RESULTS
  We found that the AAS was a reliable measure (Cronbach's Coefficient Alpha =0.85) in the patient population studied. Factor analyses identified three subscales (sedentary activities; ambulatory activities; work and exercise activities). Construct validity was demonstrated by a correlation of 0.65 between the AAS and the physical functioning (PF) dimension of the SF-36 (p < 0.001); comparisons between clinical subgroups further confirmed its validity (p < 0.001). Patients reporting improvement on the physical functioning dimension after surgery showed an effect size of 1.20 for preoperative-postoperative change in their AAS scores.
  
  
  CONCLUSIONS
  The AAS has been demonstrated to be a reliable, valid, and clinically responsive instrument that can be used to evaluate patient functioning after hernia surgery. It is easy to administer and requires less than 5 minutes of patient time to complete. This measurement system may prove useful in assessing surgical outcomes in both research and office practice settings.
authors.affiliation: Department of Preventive Medicine, Feinberg School of Medicine, Northwestern University, Chicago, IL 60611, USA.
authors.forename: Martin
authors.initials: M
authors.lastname: McCarthy
authors.forename: Olga
authors.initials: O
authors.lastname: Jonasson
authors.forename: Chih-Hung
authors.initials: CH
authors.lastname: Chang
authors.forename: A Simon
authors.initials: AS
authors.lastname: Pickard
authors.forename: Anita
authors.initials: A
authors.lastname: Giobbie-Hurder
authors.forename: James
authors.initials: J
authors.lastname: Gibbs
authors.forename: Perry
authors.initials: P
authors.lastname: Edelman
authors.forename: Robert
authors.initials: R
authors.lastname: Fitzgibbons
authors.forename: Leigh
authors.initials: L
authors.lastname: Neumayer
mesh_terms: D000203:Activities of Daily Living; D000328:Adult; D000368:Aged; D000369:Aged, 80 and over; D001294:Attitude to Health; D015897:Comorbidity; D003430:Cross-Sectional Studies; D004192:Discrimination, Psychological; D015987:Effect Modifier, Epidemiologic; D005163:Factor Analysis, Statistical; D005500:Follow-Up Studies; D006304:Health Status; D006552:Hernia, Inguinal / Q000523:psychology / Q000601:surgery*; D006801:Humans; D010535:Laparoscopy / Q000009:adverse effects / Q000523:psychology; D007813:Laparotomy / Q000009:adverse effects / Q000523:psychology; D008297:Male; D008875:Middle Aged; D011182:Postoperative Care / Q000379:methods* / Q000523:psychology / Q000592:standards; D011594:Psychometrics; D011788:Quality of Life; D011795:Surveys and Questionnaires / Q000592:standards*; D013997:Time Factors; D016896:Treatment Outcome