title: Validation of the Japanese version of the Systemic Lupus Activity Questionnaire that includes physician-based assessments in a large observational cohort.
abstract: The Systemic Lupus Activity Questionnaire (SLAQ) is a patient-reported outcome for systemic lupus erythematosus (SLE). We aimed to translate it into Japanese and further investigate its validity and reliability. The English version of the SLAQ was translated into Japanese and administered to Japanese SLE patients at our university clinic. Physicians assessed disease activity using the SLE Disease Activity Index 2000 (SLEDAI-2K). The patients were prospectively followed for repeat assessment a year later. Ultimately, 255 patients participated. The patients' 10-point ratings of disease activity and SLAQ scores were significantly correlated (Spearman's ρ = 0.53). The SLAQ score was weakly correlated with the SLE Disease Activity Index 2000 (SLEDAI-2K)-nolab (omitting laboratory items; ρ = 0.18) but not with the SLEDAI-2K (ρ = 0.02). These results suggested its convergent and discriminant validity. The SLAQ demonstrated acceptable internal consistency (Cronbach's α = 0.80), and good test-retest reliability (intraclass correlation coefficient = 0.85). The effect sizes and the standardized response means of the SLAQ were as follows: clinical worsening, 0.26 and 0.31, and improvement, -0.39 and -0.41, respectively, which indicated a small but significant responsiveness. The Japanese version of the SLAQ demonstrated acceptable reliability and validity; its performance was comparable to that of the original version.
authors.affiliation: The Institute of Rheumatology, Tokyo Women's Medical University, Tokyo, Japan.
authors.forename: Y
authors.initials: Y
authors.lastname: Okamoto
authors.affiliation: The Institute of Rheumatology, Tokyo Women's Medical University, Tokyo, Japan katsumata@ior.twmu.ac.jp.
authors.forename: Y
authors.initials: Y
authors.lastname: Katsumata
authors.affiliation: The Institute of Rheumatology, Tokyo Women's Medical University, Tokyo, Japan.
authors.forename: S
authors.initials: S
authors.lastname: Baba
authors.affiliation: The Institute of Rheumatology, Tokyo Women's Medical University, Tokyo, Japan.
authors.forename: Y
authors.initials: Y
authors.lastname: Kawaguchi
authors.affiliation: The Institute of Rheumatology, Tokyo Women's Medical University, Tokyo, Japan.
authors.forename: T
authors.initials: T
authors.lastname: Gono
authors.affiliation: The Institute of Rheumatology, Tokyo Women's Medical University, Tokyo, Japan.
authors.forename: M
authors.initials: M
authors.lastname: Hanaoka
authors.affiliation: The Institute of Rheumatology, Tokyo Women's Medical University, Tokyo, Japan.
authors.forename: H
authors.initials: H
authors.lastname: Kawasumi
authors.affiliation: The Institute of Rheumatology, Tokyo Women's Medical University, Tokyo, Japan.
authors.forename: H
authors.initials: H
authors.lastname: Yamanaka
mesh_terms: D000328:Adult; D000368:Aged; D016002:Discriminant Analysis; D005260:Female; D006801:Humans; D007564:Japan; D008137:Longitudinal Studies; D008180:Lupus Erythematosus, Systemic / Q000175:diagnosis*; D008297:Male; D008875:Middle Aged; D010819:Physician's Role; D011237:Predictive Value of Tests; D011446:Prospective Studies; D015203:Reproducibility of Results; D012720:Severity of Illness Index; D011795:Surveys and Questionnaires; D013997:Time Factors; D014175:Translating; D055815:Young Adult
keywords: Systemic lupus erythematosus; outcome measures