To determine in a historical inception cohort the impact of lupus nephritis at disease onset in short-term accrual 2019 European League Against Rheumatism (EULAR)/American College of Rheumatology (ACR) domains. The possible association with treatment and damage was also investigated.
One hundred thirty-three consecutive adult systemic lupus erythematosus patients according to the 2019 EULAR/ACR criteria were divided according to the presence (RENAL-lupus) or absence of renal involvement (NONRENAL-lupus) at disease onset. The 2019 EULAR/ACR score and Systemic Lupus International Collaborating Clinics/ACR (SDI) were longitudinally evaluated over 3 years.
RENAL-lupus (n = 49 [36.8%]) and NONRENAL-lupus (n = 84 [63.2%]) were similar regarding age (p = 0.704), female sex (p = 0.313), and black race (p = 0.506). At study entry, RENAL-lupus had higher 2019 EULAR/ACR total domains (30 [12–42] vs. 22 [10–36], p < 0.001) and used more often glucocorticoid (p < 0.001), mycophenolate mofetil (p = 0.007), and cyclophosphamide (p = 0.001). After 3 years, a stable number of domain scores was observed for the RENAL-lupus (30 [12–42] vs. 30 [12–42], p = 0.125), whereas an increase was observed for the NONRENAL-lupus (22 [10–36] vs. 23 [10–40], p < 0.001) compared with baseline. Accordingly, RENAL-lupus patients had a lower frequency of additional domains (3/49 [6.1%] vs. 37/84 [44.0%], p < 0.0001). New kidney involvement occurred in 15 (44.1%) of 34 patients of the NONRENAL-lupus. Both groups evolved with a comparable increase in frequency of patients with damage (SDI ≥1) at the end of the study (23/49 [46.9%] vs. 34/89 [40.54%], p = 0.585) with a similar median of SDI (1 [0–4] vs. 0 [0–2], p = 0.132).
The distinct pattern of accrual 2019 EULAR/ACR domains in patients with and without nephritis at disease onset suggests that close surveillance for additional organ involvement, including kidney, is mandatory in NONRENAL lupus in the first 3 years of disease. The unexpected comparable early damage in both groups despite milder disease and less intense immunosuppression in NONRENAL lupus reinforces the need for new and tailored therapies for these patients.