Background/Purpose: disease activity in Systemic Lupus Erythematosus (SLE) leads to damage, comorbidities and increased overall mortality. Frequent assessment is needed to adapt patients’ management. The Systemic Lupus Activity Questionnaire (SLAQ) is a patient self-reported instrument to screen for disease activity outside the clinical setting. Our aim was to validate the SLAQ in Spanish and evaluate its association with other validated disease activity scores.

Methods: The SLAQ questionnaire was translated and adapted in Spanish. For its validation, we included consecutive SLE patients (fulfilling the 1997 ACR classification criteria) from 3 Rheumatology centers in Argentina who responded the questionnaire. A rheumatologist blinded to S-SLAQ results examined each patient and completed a SLEDAI and Physician’s Global Assessment (PGA). Internal consistency (Cronbach’s alpha), test-retest reliability (intraclass correlation coefficient), and construct validity (Spearman’s correlation coefficient) were examined. We further evaluated the questionnaire in a larger cohort of consecutive patients from 8 Rheumatology centers. Correlations with SLAM, SLAM-no lab, SLEDAI and Patient’s Global Assessment (PGA2) were assessed (Pearson’s correlation coefficient). Sensitivity, specificity, and positive and negative predictive values for clinically significant disease activity (SLEDAI ≥6) of different S-SLAQ cut-off points (ranging 0-35) were evaluated.

Results: In the first part of the validation, we included 40 patients [97% female, mean age 40 SD13)], with a median disease duration of 116 months (IQR 49-112). The median time of answering was 2.65 minutes (IQR 1.46-4.83). The internal consistency was good to excellent (Cronbach’s alpha=0.84, p<0.001) and the intraclass correlation coefficient was 0.95 (p<0.001). Correlation with other scores was weak (SLEDAI rs=0.1, PGA rs=0.2). In the larger cohort where we continued to evaluate construct validity, we included 97 consecutive patients ([93% female, mean age: 40 years (SD14.7)]. 42% were “Mestizos”, 33% Amerindians and 25% Caucasians. Mean score of S-SLAQ was 8.24 (SD 7.31); mean SLAM-no lab was 2.06 (SD 2.38); mean SLAM was 3.68 (SD 3.17), mean SLEDAI-2K was 2.75 (SD 3.96) and mean PGA2 was 0.52 (SD 0.79). No differences in SLAQ score were detected when comparing different gender, ethnic, educational and socioeconomic groups. Correlation of S-SLAQ with PGA2 was moderate (r= 0.63 p< 0.001); and weak with SLAM-no lab (r=0.42, p<0,001) and SLAM-R (r=0.38, p<0.0001). It was very weak with SLEDAI-2K (r= 0.15, p=0.1394). Using the S-SLAQ cut-off of five points the sensitivity was 72.2 % and specificity 37.9 %, for clinically significant disease activity (SLEDAI 2K ≥ 6).

Conclusion: The S-SLAQ showed good validity and reliability. A good correlation was observed with patient´s global disease activity. No correlation was found between S-SLAQ and standard disease activity measures like SLEDAI 2K and SLAM. The S-SLAQ cut-off point of 5 showed a good sensitivity to identify the active SLE population and therefore could be an appropriate screening instrument for disease activity in clinical and epidemiological studies.

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ACR Meeting Abstracts - https://acrabstracts.org/abstract/validation-and-evaluation-of-the-spanish-version-of-the-systemic-lupus-activity-questionnaire-in-an-argentine-population/