When patients with systemic lupus erythematosus (SLE) with biopsy-proven late-onset lupus nephritis (LN) were compared with patients demonstrating a more typical early-onset LN presentation, researchers found similar clinical, serologic, and histologic features at baseline and during follow-up, indicating comparable severity and long-term outcomes between the 2 groups, according to study findings published in Lupus.
Most cases of LN occur within 5 years after SLE diagnosis, but there are exceptions in which LN does not appear until considerably later (>5 years post-diagnosis). With only a few studies conducted that compared early- and late-onset LN, it remains unclear whether onset timing affects disease outcome and severity. Investigators sought to fill this knowledge gap by comparing the 2 groups.
A retrospective observational study enrolled 93 rheumatology patients with biopsy-confirmed LN and at least 7 years of follow-up. Participants were divided into late-onset (n=18; mean age, 49.17; 94% women) and early-onset (n=75; mean age, 44.11 years; 89% women) groups. Participants were <50 years and had been diagnosed after 2000, with SLE as the only identified autoimmune condition. Several variables, including the Systemic Lupus Erythematosus Disease Activity Index (SLEDAI) score, were recorded at baseline and at follow-up. Measures of long-term outcome included the Systemic Lupus International Collaborating Clinics Damage Index (SLICC-DI) score.
As expected, mean LN presentation time following SLE diagnosis was significantly greater in late- vs early-onset participants (10.94 vs 1.20 years; P <.0001). Participants in the late-onset group were diagnosed with LN at an older age (35.0 vs 29.2 years; P =.02). Duration of nephritis was similar in the late- and early-onset groups (12.44 vs 13.28 years; P =.41).
Baseline severity indicators were similar between the late- and early-onset groups in terms of SLEDAI scores (8 vs 12; P =.47), creatinine levels (1.36 vs 1.36 mg/dL; P =.99), proteinuria (3.77 vs 5.01 g/vol; P =.26), albumin levels (2.84 vs 2.59 mg/dL; P =.30), and rates of proliferative nephritis (44% vs 60%; P =.23).
Long-term outcome measures were also comparable in the late- and early-onset groups, including SLICC-DI (1.0 vs 0.5; P =.27), rates of dialysis (22% vs 13%; P =.46), creatinine levels (2.04 vs 1.69 mg/dL; P =.56), and mortality rates (0% vs 12%; P =.19). Medications were used for induction and maintenance at similar frequencies, and the rates of renal flares were also comparable between groups (50% vs 37%; P =.32).
Study strengths included biopsy confirmation of LN, long-term follow-up, histopathology performed in all patients at LN onset, and exclusion of patients >50 years or patients with additional autoimmune diagnoses.
Study limitations included a retrospective design and a small late-onset sample size that could decrease analytical power.
The authors noted that the data suggest, “that there should be no distinct treatment targets and therapeutic interventions for the late- and early-onset groups.”
Ugolini-Lopes MR, Santos LPS, Stagnaro C, Seguro LPC, Mosca M, Bonfá E. Late-onset biopsy-proven lupus nephritis without other associated autoimmune diseases: severity and long-term outcome [published online November 15, 2018]. Lupus. doi:10.1177/0961203318811603