Validation of childhood lupus specific targets: ensuring accurate assessment of disease control in younger, lighter paediatric patients.

Abstract

To validate novel childhood-onset systemic lupus erythematosus (cSLE) treat-to-target targets including childhood lupus low disease activity state (cLLDAS), cSLE clinical remission on steroids (cCR) and cSLE clinical remission off steroids (cCR-0), as compared with adult-onset SLE (aSLE) targets. Attainment of the aforementioned cSLE-specific and aSLE-specific targets (LLDAS, DORIS 2021 Remission) was assessed at each visit in UK JSLE Cohort Study patients. Univariable and multivariable Prentice-Williams-Peterson (PWP) gap-time models investigated the impact of target attainment on new damage and severe flare. The cohort included 430 cSLE patients. Attainability was comparable between corresponding cSLE and aSLE targets. Achieving cLLDAS (hazard ratio [HR] 0.18 [95% CI: 0.14, 0.23]), cCR (HR 0.18 [0.13, 0.23]) and cCR-0 (HR 0.17 [0.13, 0.23]) reduced the risk of severe flare (all P < 0.001). Risk of new damage was reduced in those reaching cLLDAS (HR 0.22 [0.11, 0.44]), cCR (HR 0.25 [0.13, 0.49]) and cCR-0 (HR 0.30 [0.15, 0.60]) (all P < 0.001). Inappropriate attainment of LLDAS and DORIS remission occurred at 35 and 52 visits, respectively, in younger (median age 7.3 and 8.8 years, respectively) and lighter (median weight 26.8 and 37.1 kg, respectively) patients whilst on prednisolone doses that precluded cSLE target attainment (median 0.17 [IQR 0.16-0.24] and 0.13 [IQR 0.11-0.16] mg/kg/day, respectively). This study validates novel paediatric-specific targets, demonstrating that achieving cLLDAS, cCR and cCR-0 reduces risks of new damage and severe flare, which is comparable to aSLE targets. Using cSLE-specific targets prevents misclassification of disease activity in paediatric patients, enabling more accurate disease control assessments in younger, lighter patients.