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Development and initial validation of a self‐assessed lupus organ damage instrument
Author(s) -
Costenbader Karen H.,
Khamashta Munther,
RuizGarcia Silvia,
PerezRodriguez Maria Teresa,
Petri Michelle,
Elliott Jennifer,
Manzi Susan,
Karlson Elizabeth W.,
TurnerStokes Tabitha,
Bermas Bonnie,
Coblyn Jonathan,
Massarotti Elena,
Schur Peter,
Fraser Patricia,
Navarro Iris,
Hanly John G.,
Shaver Timothy S.,
Katz Robert S.,
Chakravarty Eliza,
Fortin Paul R.,
Sanchez Martha L.,
Liu Jigna,
Michaud Kaleb,
Alarcón Graciela S.,
Wolfe Frederick
Publication year - 2010
Publication title -
arthritis care and research
Language(s) - English
Resource type - Journals
SCImago Journal Rank - 2.032
H-Index - 163
eISSN - 2151-4658
pISSN - 2151-464X
DOI - 10.1002/acr.20193
Subject(s) - medicine , rheumatology , systemic lupus erythematosus , patient reported outcome , gold standard (test) , lupus erythematosus , physical therapy , comorbidity , quality of life (healthcare) , immunology , antibody , nursing , disease
Objective The Systemic Lupus International Collaborating Clinics/American College of Rheumatology Damage Index (SDI) is a validated instrument for assessing organ damage in systemic lupus erythematosus (SLE). Trained physicians must complete it, thus limiting utility where this is impossible. Methods We developed and pilot tested a self‐assessed organ damage instrument, the Lupus Damage Index Questionnaire (LDIQ), in 37 SLE subjects and 7 physicians. After refinement, 569 English‐speaking SLE subjects and 14 rheumatologists from 11 international SLE clinics participated in validation. Subjects and physicians completed the instruments separately. We calculated sensitivity, specificity, Spearman's correlations, and agreement using the SDI as the gold standard. Six hundred five SLE participants in the community‐based National Data Bank for Rheumatic Diseases (NDB) study completed the LDIQ and we assessed correlations with outcome and disability measures. Results The mean LDIQ score was 3.3 (range 0–16) and the mean SDI score was 1.5 (range 0–9). The LDIQ had a moderately high correlation with the SDI (Spearman's r = 0.50, P < 0.001). Specificities of individual LDIQ items were >80%, except for neuropathy. Sensitivities were variable and lowest for damage, with <1% prevalence. Agreement between the SDI and LDIQ was >85% for all but neuropathy, reduced renal function, deforming arthritis, and alopecia. In the NDB, the LDIQ correlated well with the comorbidity index (r = 0.45), the Short Form 36 physical component scale (r = 0.43), the Medical Research Council dyspnea scale (r = 0.40), disability (r = 0.37), and the Systemic Lupus Erythematosus Activity Questionnaire score (r = 0.37). Conclusion The metric properties of the LDIQ are good compared with the SDI. It has construct validity and correlations with health assessments similar to the SDI. The LDIQ should allow expansion of SLE research. Its ultimate value will be determined in longitudinal studies.