Late-onset systemic lupus erythematosus in Northwestern Spain: differences with early-onset systemic lupus erythematosus and literature review

Abstract

To further investigate into the epidaemiology of systemic lupus erythematosus (SLE) in Southern Europe, we have assessed the incidence, clinical spectrum and survival of patients diagnosed with late-onset SLE (age ≥ 50 years) according to the 1982 American College of Rheumatology (ACR) classification criteria at the single hospital for a well-defined population of Lugo, Northwestern (NW) Spain. Between January 1987 and December 2006, 51 (39.3%) of the 150 patients diagnosed as having SLE fulfilled definitions for late-onset SLE. The predominance of women among late-onset SLE (4:1) was reduced when compared with that observed in early-onset SLE (7:1). However, the incidence of late-onset SLE was significantly higher in women (4.2 [95% confidence interval (CI): 3.1–5.6] per 100,000 population) than in men (1.3 [95% CI: 0.6–2.2] per 100,000 population) (p < 0.001). As observed in early-onset SLE, the most frequent clinical manifestation in patients with late-onset SLE was arthritis (71.2%). Renal disease was less common in late-onset SLE (13.5%) than in early-onset SLE (26.4%); p = 0.07). In contrast, secondary Sjögren syndrome was more commonly found in the older age-group (27.1% versus 12.1%; p = 0.03). A non-significantly increased incidence of serositis was also observed in late-onset SLE patients (33.9% versus 22.0%; p = 0.13). Hypocomplementaemia (72.9% versus 91.2%) and positive results for anti-DNA and anti-Sm (49.2% and 6.8% versus 68.1% and 23.1, respectively) were significantly less common in late-onset SLE patients than in early-onset SLE. The probability of survival was reduced in late-onset SLE (p < 0.001). With respect to this, the 10-year and 15-year survival probability were 74.9 % and 63.3% in the late-onset SLE group and 96.3% and 91.0% in patients with early-onset SLE, respectively. In conclusion, our results confirm that in NW Spain SLE is not uncommon in individuals 50 years and older. In keeping with earlier studies, late-onset SLE patients from NW Spain have some clinical and laboratory differences with respect to those individuals with early-onset SLE. Our data support the claim of a reduced probability of survival in the older age-group of SLE patients.