Impact of serological activity on flare following clinically inactive disease and remission in childhood-onset systemic lupus erythematosus

Abstract

Abstract Objectives The objectives of this study were to assess the association between serological activity (SA) and clinical inactivity in SLE and to investigate whether SA predicts flare after the attainment of clinically inactive disease (CID) and remission. Methods The longitudinal data of children from three paediatric rheumatology referral centres were retrospectively reviewed. CID was interpreted as the beginning of a transitional phase of clinical inactivity on a moderate glucocorticoid dose during which tapering was expected and defined as the absence of disease activity in clinical domains of SLEDAI, without haemolytic anaemia or gastrointestinal activity, in patients using <15 mg/day prednisolone treatment. Modified DORIS remission on treatment criteria were used to determine remission. Results Of the 124 patients included, 89.5% displayed SA at onset. Through follow-up, the rate of SA decreased to 43.3% at first CID and 12.1% at remission. Among the patients with CID, 24 (20.7%) experienced a moderate-to-severe flare before the attainment of remission. While previous proliferative LN [odds ratio (OR): 10.2, P: 0.01) and autoimmune haemolytic anaemia (OR: 6.4, P: 0.02) were significantly associated with increased odds of flare after CID, SA at CID was not associated with flare. In contrast, 21 (19.6%) patients experienced flare in a median of 18 months after remission. Hypocomplementemia (OR: 9.8, P: 0.02) and a daily HCQ dose of <5 mg/kg (OR: 5.8, P: 0.02) during remission significantly increased the odds of flare. Conclusion SA during remission increases the odds of flare, but SA at CID does not. Suboptimal dosing of HCQ should be avoided, especially in children with SA in remission, to lower the risk of flares.