Epidemiology and burden of systemic lupus erythematosus in a Southern European population: data from the community-based lupus registry of Crete, Greece

Objectives Several population-based studies on systemic lupus erythematosus (SLE) have been reported, yet community-based, individual-case validated, comprehensive reports are missing. We studied the SLE epidemiology and burden on the island of Crete during 1999-2013. Methods Multisource case-finding included patients >= 15 years old. Cases were ascertained by the ACR 1997, SLICC 2012 criteria and rheumatologist diagnosis, and validated through synthesis of medical charts, administrative and patient-generated data. Results Overall age-adjusted/sex-adjusted incidence was 7.4 (95% CI 6.8 to 7.9) per 100 000 persons/year, with stabilising trends in women but increasing in men, and average (+/- SD) age of diagnosis at 43 (+/- 15) years. Adjusted and crude prevalence (December 2013) was 123.4 (113.9 to 132.9) and 143 (133 to 154)/10(5) (165/10(5) in urban vs 123/10(5) in rural regions, p<0.001), respectively. Age-adjusted/sex-adjusted nephritis incidence was 0.6 (0.4 to 0.8) with stable trends, whereas that of neuropsychiatric SLE was 0.5 (0.4 to 0.7) per 100 000 persons/year and increasing. Although half of prevalent cases had mild manifestations, 30.5% developed organ damage after 7.2 (+/- 6.6) years of disease duration, with the neuropsychiatric domain most frequently afflicted, and 4.4% of patients with nephritis developed end-stage renal disease. The ACR 1997 and SLICC 2012 classification criteria showed high concordance (87%), yet physician-based diagnosis occurred earlier than criteria-based in about 20% of cases. Conclusions By the use of a comprehensive methodology, we describe the full spectrum of SLE from the community to tertiary care, with almost half of the cases having mild disease, yet with significant damage accrual. SLE is not rare, affects predominantly middle-aged women and is increasingly recognised in men. Neuropsychiatric disease is an emerging frontier in lupus prevention and care.