Article Text
Abstract
Background Recently, definitions of both Remission and LLDAS have been proposed which include disease activity status and medication intake [immunosuppressive (IS) drugs and corticosteroids]. The aim of this study was to evaluate both on the outcome of SLE patients.
Materials and methods Interval was defined as the period between two SLEDAIs or between one SLEDAI and the end of the follow-up. Four disease activity statuses were defined: Remission off-therapy = SLEDAI = 0 without prednisone or IS drugs; Remission on-therapy = SLEDAI = 0 and a prednisone dose ≤5 mg/d and/or IS drugs in maintenance dose; LLDAS = SLEDAI≤4, a prednisone dose ≤7.5 mg/d and/or IS drugs in maintenance dose; and non-optimally controlled status = SLEDAI >4 and/or prednisone dose >7.5 mg/d and/or IS drugs in induction dose. Antimalarials were allowed in all groups. Predefined outcomes were mortality, new damage [defined as an increase of at least 1 point in the SLICC/ACR damage index (SDI)] and severe new damage (defined as an increase of at least 3 points in the SDI). Univariable and multivariable Cox regression models adjusted for possible confounders were performed in order to define the impact of disease activity status, as time-dependent variable, on these three outcomes.
Results One thousand three hundred and fifty patients from the GLADEL cohort, with at least two intervals, were included, including 5672 intervals. Median length of the intervals was 7.1 months (interquartile rank 5.1–11.7). Median number of intervals per patients was 4 (2–7). The most frequent interval was non-optimally controlled (4446; 78.4%), followed by LLDAS (566; 10.0%), remission on-therapy (553; 9.7%) and remission off-therapy (107; 1.9%). Seventy-nine patients died during the follow-up, 606 presented new damage and 177 severe new damage. Because of the limited number of intervals in the off-therapy group, this group was combined with the on-therapy group. The impact of these disease activity statuses on the pre-specified outcomes is depicted in Table 1. Of importance, in multivariable analyses, remission on/off therapy was associated with both, a lower risk of new damage (HR: 0.52; 95% CI: 0.37–0.72), and of severe new damage (HR: 0.32; 95% CI: 0.15–0.65); LLDAS was associated with a lower risk of severe new damage (HR: 0.46; 95% CI: 0.23–0.91). Although the HR were in the right direction for the mortality outcome, the confidence intervals were too wide, probably because of the relative low number of events in this category.
Conclusions Remission on/off therapy diminished the risk of new and severe new damage, and LLDAS diminished the risk of severe new damage after adjusting for other well-known risk factors of damage.
Acknowledgements This study was performed using data from the GLADEL cohort.