Validation and adaptation of the Spanish version of the systemic lupus activity questionnaire (S-SLAQ) in an Argentinean population.

OBJECTIVES: To validate the systemic lupus activity questionnaire (SLAQ) in Spanish language. METHODS: The SLAQ questionnaire was translated and adapted in Spanish. Consecutive SLE patients from 8 centers in Argentina were included. A rheumatologist completed a Systemic Lupus Activity Measure (SLAM), Systemic Lupus Erythematosus Disease Activity Index (SLEDAI)-2K, and a physician's assessment. Reliability was assessed by internal consistency (Cronbach's alpha), stability by test-retest reliability (intraclass correlation coefficient), and construct validity by evaluating the correlation with clinically relevant scores. Sensitivity and specificity for clinically significant disease activity (SLEDAI ≥6) of different S-SLAQ cut-off points were evaluated. RESULTS: We included 97 patients ((93% female, mean age: 40 years (SD14.7)). Internal consistency was excellent (Cronbach's alpha = 0.84, p < 0.001), and the intraclass correlation coefficient was 0.95 (p < 0.001). Mean score of S-SLAQ was 8.2 (SD 7.31). Correlation of S-SLAQ was moderate with Patient NRS (r= 0.63 p< 0.001), weak with SLAM-no lab (r = 0.42, p <0.001) and SLAM (r = 0.38, p < 0.0001), and very weak with SLEDAI-2K (r = 0.15, p =0.1394). Using the S-SLAQ cutoff of five points, the sensitivity was 72.2% and specificity was 37.9%, for clinically significant disease activity. CONCLUSIONS: The S-SLAQ showed good validity and reliability. A good correlation, similar to the original instrument, was observed with patient´s global disease activity. No correlation was found between S-SLAQ and gold standard disease activity measures like SLEDAI-2K and SLAM. The S-SLAQ cutoff 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.

Prevalence and incidence of systemic lupus erythematosus in Tucumán, Argentina.

The aim of this study was to determine the prevalence and incidence of Systemic Lupus Erythematosus (SLE) in Tucumán, Argentina. METHODS: The study included inpatient and outpatient charts from four public hospitals and private practice rheumatology clinics, all of them members of the Tucumán Rheumatology Society. Patients older than 16 years with diagnosis of SLE between January 2005 and December 2012 were included. Prevalence and annual incidence were calculated as the number of cases per 100.000 inhabitants during the period 2005 to 2012. RESULTS: Three hundred fifty-three patients were identified. The mean age at diagnosis was 30.5 ± 11.7 years, 93.5% women, 83% mestizos. Prevalence was 24.3 cases/100.000 inhabitants (CI 95% 22.6-28.8) and age-adjusted (≥16 years) of 34.9 cases/100.000 inhabitants (CI 95% 32.8-41.1). The annual incidence in 2005 was 1.8 cases/100.000 inhabitants (95% CI 1-2.9) and 2012 of 4.2 cases/100.000 inhabitants (95% CI 2.9-5.8). Mortality was 9.1%, with infections being the most frequent cause (14/32). CONCLUSION: The prevalence of SLE in the province of Tucumán was 34.9 cases/100.000 inhabitants.