title: Patient-centered psoriatic arthritis (PsA) activity assessment by Stockerau Activity Score for Psoriatic Arthritis (SASPA).
abstract: BACKGROUND
  To investigate whether a modified Rheumatoid Arthritis Disease Activity Index-5 could be applied as a routine assessment tool for psoriatic arthritis (PsA) patients.
  
  
  METHODS
  Ninety-seven PsA outpatients (mean age 49.78 years; age range 23-80 years; 49 male, 48 female), completed a prototype questionnaire. Tender and swollen joint counts, including enthesiopathy, physician's assessment of disease activity on a visual analog scale (MDglob), erythrocyte sedimentation rate, and patient satisfaction with disease status (PatSat: 1 = excellent to 5 = unsatisfactory) were recorded. Factorial analysis was performed and alpha, as a measure of reliability, and tau were calculated. The ultimate five-item questionnaire, calculated by (Q1 + Q2 + Q3 + Q4 + Q5)/5, was then handed over to 152 PsA outpatients (mean age 54.02 years; age range 26-80 years; 82 male, 70 female), and analyzed accordingly.
  
  
  RESULTS
  Analyzing the internal consistency of the prototype questionnaire revealed the highest alpha value of 0.849, on deleting the question targeting disease course. Alpha for the final Stockerau Activity Score for Psoriatic Arthritis (SASPA) was 0.875, with all items contributing to the final result (item loading from 0.573 to 0.910). Kendall's tau for the relationship between SASPA scores and swollen joint count, tender joint count, and MDglob was 0.34, 0.416, and 0.392, respectively. The sensitivity of the questionnaire to change was demonstrated in patients starting treatment with a tumor necrosis factor blocker (standardized mean difference: 2.1).
  
  
  CONCLUSIONS
  The SASPA questionnaire constitutes a fully patient-administered tool to monitor PsA activity. Its reliability, convergent validity, and sensitivity to change were demonstrated.
authors.affiliation: 2nd Department of Medicine, Center for Rheumatology, Lower Austria, State Hospital Stockerau, Karl Landsteiner Institute for Clinical Rheumatology, Landstrasse 18, A-2000, Stockerau, Austria. burkhard.leeb@stockerau.lknoe.at.|Private Rheumatology Office, Babogasse 20, A-2020, Hollabrunn, Austria. burkhard.leeb@stockerau.lknoe.at.|Department for Rheumatology and Immunology, Medical University of Graz, Auenbruggerplatz 2, A-8036, Graz, Austria. burkhard.leeb@stockerau.lknoe.at.
authors.forename: Burkhard F
authors.initials: BF
authors.lastname: Leeb
authors.affiliation: 2nd Department of Medicine, Center for Rheumatology, Lower Austria, State Hospital Stockerau, Karl Landsteiner Institute for Clinical Rheumatology, Landstrasse 18, A-2000, Stockerau, Austria. piahai@gmx.net.
authors.forename: Pia M
authors.initials: PM
authors.lastname: Haindl
authors.affiliation: Department for Rheumatology and Immunology, Medical University of Graz, Auenbruggerplatz 2, A-8036, Graz, Austria. hans-peter.brezinsek@medunigraz.at.
authors.forename: Hans-Peter
authors.initials: HP
authors.lastname: Brezinschek
authors.affiliation: 2nd Department of Medicine, Center for Rheumatology, Lower Austria, State Hospital Stockerau, Karl Landsteiner Institute for Clinical Rheumatology, Landstrasse 18, A-2000, Stockerau, Austria. the-hien-harsono.mai@stockerau.lknoe.at.
authors.forename: Harsono T H
authors.initials: HT
authors.lastname: Mai
authors.affiliation: 2nd Department of Medicine, Center for Rheumatology, Lower Austria, State Hospital Stockerau, Karl Landsteiner Institute for Clinical Rheumatology, Landstrasse 18, A-2000, Stockerau, Austria. christoph.deutsch@stockerau.lknoe.at.
authors.forename: Christoph
authors.initials: C
authors.lastname: Deutsch
authors.affiliation: 2nd Department of Medicine, Center for Rheumatology, Lower Austria, State Hospital Stockerau, Karl Landsteiner Institute for Clinical Rheumatology, Landstrasse 18, A-2000, Stockerau, Austria. b.rintelen@gmx.at.
authors.forename: Bernhard
authors.initials: B
authors.lastname: Rintelen
mesh_terms: D000328:Adult; D000368:Aged; D000369:Aged, 80 and over; D015535:Arthritis, Psoriatic / Q000175:diagnosis*; D005260:Female; D006801:Humans; D008297:Male; D008875:Middle Aged; D015203:Reproducibility of Results; D012680:Sensitivity and Specificity; D012720:Severity of Illness Index; D011795:Surveys and Questionnaires / Q000592:standards*; D064232:Visual Analog Scale