Objective

To assess the reliability and criterion and construct validity of the self-administered Brief Index of Lupus Damage (SA-BILD), a patient-reported measure of organ damage in systemic lupus erythematosus (SLE).

Methods

The validity of the SA-BILD was assessed using data from the Georgians Organized Against Lupus (GOAL) survey. GOAL is a longitudinal cohort of SLE patients predominantly derived from the Georgia Lupus Registry, a population-based registry established in Atlanta, Georgia. In total, 711 participants with documented SLE completed the SA-BILD. To test reliability, the SA-BILD was readministered to 32 patients. Criterion validity was examined in 150 respondents for whom the Systemic Lupus International Collaborating Clinics/American College of Rheumatology Damage Index (SDI) was also completed. Construct validity was assessed among 711 GOAL participants by dividing the SA-BILD scores into quartiles and examining the association with demographics, health status, and health care utilization.

Results

The test-retest correlation score was 0.93 (P < 0.0001), the item-by-item agreement with the SDI was >80% for most SA-BILD items, and the Spearman's rho correlation coefficient for the SDI and SA-BILD was moderately high (ρ = 0.59, P < 0.0001). SA-BILD scores showed significant associations in the expected directions with age, disease duration, disease activity, overall health, comorbidity index, and physician visits.

Conclusion

The SA-BILD was reliable and had very good or good criterion validity compared with the SDI when tested in a predominantly African American cohort of US SLE patients. Associations of SA-BILD scores with sociodemographics and health status were consistent with previous studies. These findings support the use of the SA-BILD as a valid measure of patient-reported damage in SLE.

Background: Estimating the burden of disease attributable to long-term exposure to fine particulate matter (PM2.5) in ambient air requires knowledge of both the shape and magnitude of the relative risk (RR) function. However, adequate direct evidence to id

Objective

Anti-C1q has been associated with systemic lupus erythematosus (SLE) and lupus nephritis in previous studies. We studied anti-C1q specificity for SLE (vs rheumatic disease controls) and the association with SLE manifestations in an international multicenter study.

Methods

Information and blood samples were obtained in a cross-sectional study from patients with SLE (n = 308) and other rheumatologic diseases (n = 389) from 25 clinical sites (84% female, 68% Caucasian, 17% African descent, 8% Asian, 7% other). IgG anti-C1q against the collagen-like region was measured by ELISA.

Results

Prevalence of anti-C1q was 28% (86/308) in patients with SLE and 13% (49/389) in controls (OR = 2.7, 95% CI: 1.8-4, p < 0.001). Anti-C1q was associated with proteinuria (OR = 3.0, 95% CI: 1.7-5.1, p < 0.001), red cell casts (OR = 2.6, 95% CI: 1.2-5.4, p = 0.015), anti-dsDNA (OR = 3.4, 95% CI: 1.9-6.1, p < 0.001) and anti-Smith (OR = 2.8, 95% CI: 1.5-5.0, p = 0.01). Anti-C1q was independently associated with renal involvement after adjustment for demographics, ANA, anti-dsDNA and low complement (OR = 2.3, 95% CI: 1.3-4.2, p < 0.01). Simultaneously positive anti-C1q, anti-dsDNA and low complement was strongly associated with renal involvement (OR = 14.9, 95% CI: 5.8-38.4, p < 0.01).

Conclusions

Anti-C1q was more common in patients with SLE and those of Asian race/ethnicity. We confirmed a significant association of anti-C1q with renal involvement, independent of demographics and other serologies. Anti-C1q in combination with anti-dsDNA and low complement was the strongest serological association with renal involvement. These data support the usefulness of anti-C1q in SLE, especially in lupus nephritis.