Background Systemic lupus erythematosus (SLE) predominantly affects young women in the third decade of life. A small subset of patients develops SLE after 50 years of age. There is controversy whether older-onset SLE is associated with a more benign disease course than younger-onset SLE.

Objectives To compare disease activity, clinical and immunological features as well as the rate and cause of mortality between 535 SLE patients with early or late onset, diagnosed according to ACR criteria revised in 1997, attending our outpatients’ clinic from 1976 to 2008.

Methods Patients were divided in two groups according to the onset of SLE before or after 50 years of age. Forty patients (7.5%) presented a late onset (Group A), while 495 (92.5%) (Group B) showed an early onset of SLE. Clinical data (musculo-skeletal manifestations, mucocutaneous symptoms, constitutional symptoms, serositis, mayor organ involvement and symptoms related to antiphospholipid antibodies syndrome), laboratory and immunological assessment (C3, C4, CH50, rheumatoid factor, antinuclear anti-dsDNA antibodies, anti-ENA, anticardiolipin and anti-beta 2 glycoprotein I antibodies, Lupus anticoagulant) were derived from the clinical records. Disease activity was measured by ECLAM score (1) at the time of SLE diagnosis. The two groups were compared by Student’s t test, Chi square or Fisher’s exact tests when required.

Results Comparing the clinical features of SLE, sicca symptoms were significantly more frequent in group A (p<0.015), while glomerulonephritis was prevalent in early onset SLE (p<0.016). Analyzing the immunological features, we found that C3 was more frequently reduced in group B (p<0.0005) as well as ANA were more frequently detected in group B (p<0.02). No difference was detected for anti-dsDNA, anti-phospholipid or anti-ENA antibodies’ distribution between groups.The mean of ECLAM score was 3.69 (±1.5) in Group A versus 4.11 (±2.3) in Group B. A total of 22 patients (4.25%) died during follow-up: 14 in group B (2.8%) and 8 in group A (20%). Duration of follow -up in the two groups was not significantly different even if group B was followed for 14.9 years (SD: 9.5) and group A for 11 years (SD: 6.3). ECLAM scored 4.12 (±1.09) in Group A versus 5.03 (±2.3) in Goup B of patient who died during follow-up.

The most frequent cause of death was represented by infections in group B (28.5%) and cardiovascular (CV) events in group A (50%). Myocardial infarction and stroke rates did not differ in the two groups (21.5% in group B vs 25% in group A) and they are invariably associated to anti-phospholipid antibodies.

Conclusions Late onset SLE occurred in 7,5% of patients and differed from early onset SLE for a more frequent occurrence of sicca and lower prevalence of nephritis, C3 reduction and ANA positivity. Deaths occurred more frequently in late onset SLE mainly for CV involvement. Disease activity as measured by ECLAM was slightly higher in Group B versus Group A while not significantly different.

1. Vitali C, Bencivelli W, Bombardieri S et al. Clin Exp Rheumatol. 1992;10:541-7.

Disclosure of Interest None Declared