The Systemic Lupus Activity Measure-Revised, the Mexican Systemic Lupus Erythematosus Disease Activity Index (SLEDAI), and a Modified SLEDAI-2K Are Adequate Instruments to Measure Disease Activity in Systemic Lupus Erythematosus

AMÉRICA G. URIBE, LUIS M. VILÁ, GERALD McGWIN Jr, MARTHA L. SANCHEZ, JOHN D. REVEILLE, and GRACIELA S. ALARCÓN

ABSTRACT.

Objective. To assess the validity, reliability, and feasibility of the Systemic Lupus Activity Measure-Revised (SLAM-R), the Mexican version of the Systemic Lupus Erythematosus Disease Activity Index (MEX-SLEDAI), and a Modified SLEDAI-2000 (SLEDAI-2K) compared with the SLEDAI-2K in a multiethnic population of patients with SLE.

Methods. We studied 92 SLE patients from 3 US geographic areas (Alabama, Texas, and Puerto Rico). Assessment occurred during regular outpatient, inpatient, or study encounters. A trained physician scored the 4 instruments and also assessed disease activity globally [physician global assessment (PGA)]. Convergent (with SLEDAI-2K) and construct validity (with PGA) were determined by Spearman rank (r_s) correlation test. Level of agreement between the instruments was assessed using Bland-Altman plots. Discriminant validity (distinguishing clearly active vs mildly/nonactive disease) was assessed considering the SLEDAI-2K (and the PGA) as the gold standard. Feasibility was explored by cost analyses.

Results. The SLAM-R, the MEX-SLEDAI, and the Modified SLEDAI-2K were highly correlated with the SLEDAI-2K (r_s = 0.566, 0.755, 0.924, respectively) and with the PGA (r_s = 0.650, 0.540, 0.634, respectively). The 3 instruments showed good agreement with the SLEDAI-2K (Bland-Altman plots). The Modified SLEDAI-2K had better discriminant validity than the SLAM-R and the MEX-SLEDAI. The Modified SLEDAI-2K was the least expensive instrument.

Conclusion. The SLAM-R, the MEX-SLEDAI, and the Modified SLEDAI-2K are adequate options for assessment of SLE disease activity; they are also less costly than the SLEDAI-2K. (J Rheumatol 2004;31:1934-40)

Key Indexing Terms:

DISEASE ACTIVITY
SYSTEMIC LUPUS ACTIVITY MEASURE-REVISED
MEXICAN SYSTEMIC LUPUS ERYTHEMATOSUS DISEASE ACTIVITY INDEX
SYSTEMIC LUPUS ERYTHEMATOSUS
SLEDAI-2K

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From the Departments of Medicine (Division of Clinical Immunology and Rheumatology), Surgery (Section of Trauma, Burns, and Critical Care), and Epidemiology, Schools of Medicine and Public Health, The University of Alabama at Birmingham, Birmingham, Alabama, USA; Division of Rheumatology, The University of Puerto Rico Medical Sciences Campus, San Juan, Puerto Rico; and the Division of Rheumatology and Clinical Immunogenetics, The University of Texas Health Science Center, Houston, Texas, USA.

Supported by The Kirkland Scholar Award Program, NIAMS Grant R01-AR42503, and NCRR/NIH RCMI Clinical Research Infrastructure Initiative 1P20-RR11126.

A.G. Uribe, MD, Mary Kirkland Research Fellow in Rheumatology; M.L. Sanchez, MD, MPH, Study Coordinator; G.S. Alarcón, MD, MPH, Jane Knight Lowe Chair of Medicine in Rheumatology, Department of Medicine; G. McGwin Jr, PhD, Associate Professor, Departments of Surgery and Epidemiology, Schools of Medicine and Public Health, University of Alabama; L.M. Vilá, MD, Associate Professor and Chief, Division of Rheumatology, University of Puerto Rico Medical Sciences Campus; J.D. Reveille, MD, George S. Bruce Professor in Arthritis and Other Rheumatic Disorders, Director, Division of Rheumatology and Clinical Immunogenetics, University of Texas Health Science Center.

Address reprint requests to Dr. G.S. Alarcón, 830 FOT, The University of Alabama at Birmingham, Birmingham, AB 35294. E-mail: graciela.alarcon@ccc.uab.edu

Submitted August 26, 2003; revision accepted April 5, 2004.

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