To further investigate the epidemiology of systemic lupus erythematosus (SLE) in southern Europe, we assessed the incidence, prevalence, clinical spectrum of the disease, flares, and survival of patients diagnosed with SLE in the Lugo region of northwestern Spain. Between January 1987 and December 2006, 150 Lugo residents were diagnosed as having SLE according to the 1982 American College of Rheumatology criteria for the classification of SLE. Women outnumbered men (127 [84.7%] vs. 23 [15.3%]). The mean age at the time of disease diagnosis was 46.1 ± 19.6 years. The mean follow-up from the time of disease diagnosis was 7.8 ± 4.5 years. The age- and sex-adjusted annual incidence rate over the 20-year study period was 3.6 (95% confidence interval [CI], 3.0-4.2) per 100,000 population aged 15 years and older. The overall annual incidence rate over the 20-year study period in women (5.9/100,000 population aged ≥ 15 yr; 95% CI, 4.9-7.0) was higher than in men (1.1/100,000 population aged ≥ 15 yr; 95% CI, 0.7-1.7) (p < 0.001). By December 31, 2006, the overall age-adjusted SLE prevalence in the Lugo region for patients who fulfilled at least 4 of 1982 American College of Rheumatology criteria was 17.5 per 100,000 population aged 15 years and older (95% CI, 12.6-24.1). Prevalence in women (29.2/100,000 population aged ≥ 15 yr; 95% CI, 20.0-40.7) was higher than in men (5.8/100,000 population aged ≥ 15 yr; 95% CI, 2.0-12.0). The most frequent clinical manifestation was arthritis. As reported in population-based studies on SLE patients of European descent, renal disease was observed in only 27.3% of the patients. The rate of flares was 0.084/year. A younger age and the presence of nephritis at the time of disease diagnosis were associated with the development of flares during the follow-up of Lugo patients. Compared with the general population the probability of survival in patients with SLE was significantly reduced (p = 0.04). In conclusion, the present study establishes a baseline estimate of the incidence and clinical spectrum of SLE in northwestern Spain. According to our results, the incidence of SLE in northwestern Spain is slightly higher than that reported in most European regions. Patients with SLE from northwestern Spain have a later average age onset and a lower frequency of nephritis than in the African-American population. However, our data show a reduced probability of survival in Spanish patients with SLE.

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.