Comparison of the Systemic Lupus Erythematosus Activity Questionnaire and the Systemic Lupus Erythematosus Disease Activity Index in a Black Barbadian Population
In Barbados, use of the Systemic Lupus Erythematosus (SLE) Disease Activity Index (SLEDAI) is limited by the unavailability of serologic markers. The SLE Activity Questionnaire (SLAQ) excludes laboratory measurements and is therefore more accessible. Here, we investigate the agreement between the SLAQ, the SLEDAI, and the physician global assessment (PGA). A pilot of 32 participants completed the SLAQ and SLEDAI. The tools were compared (1) in their original format, (2) limited to common indices, and (3) limited to the same patient recall period. We compared the proportions of persons reporting disease activity and the concordance between calculated activity scores for SLAQ versus SLEDAI and for SLAQ versus PGA. Seventy-eight percent versus 59% of participants reported disease activity with the original SLEDAI versus SLAQ, respectively. The relationship was reversed to 22% versus 59% when the matched item tools were compared. Concordance was 0.62 (95% CI 0.42–0.81) between the original scores, 0.70 (0.57–0.83) when restricted by matched items, and 0.72 (0.59–0.84) when further restricted by recall period. Concordance between the SLAQ and PGA was 0.56 (0.32–0.80). Reversal of the disease activity percentage in the matched items comparison highlights the inadequacy of tools that exclude laboratory measurements and suggests that the subjective nature of SLAQ may contribute to over-reporting. Further work is needed to produce a robust disease activity tool apt for resource-constrained environments. 1. Introduction Systemic Lupus Erythematosus (SLE) is a multisystem autoimmune disease characterized by periods of clinical quiescence punctuated by acute disease flares. A five-year population-based study highlighted the striking disease excess among women of African descent, with crude incidence rates (per 100,000) of 0.4 for White males, 3.5 for White females, 0.7 for African-American males, and 9.2 for African-American females [1]. Mortality rates follow a similar pattern, with several studies indicating higher rates of lupus deaths among Black women compared to their Caucasian counterparts [2–5]. Some of the regions with the highest disease burden and mortality rates are also the least equipped to diagnose and manage the disease [6]. Barbados, a Caribbean nation with a population of 288,000 persons [7], 93% of African origin, has one of the highest documented incidence rates of SLE among women (12.21 per 100,000 person-years; 95% CI 10.46–14.18) [5]. Similar to the experience of African-Americans, SLE in Barbadian patients has been reported to run a
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