Arthritis & Rheumatism, Volume 63,
November 2011 Abstract Supplement

Abstracts of the American College of
Rheumatology/Association of Rheumatology Health Professionals
Annual Scientific Meeting
Chicago, Illinois November 4-9, 2011.

Incidence and Prevalence of Systemic Lupus Erythematosus in Buenos Aires, Argentina: A 11 Years Health Management Organization Based Study.

Valeiras1,  Soledad M., Marchese1,  Martin F., Talani1,  Alejandro S., Avellaneda1,  Nicolas L., Etchepare1,  Alvaro, Etchepare1,  Patricio, Plou1,  Maria S.

Instituto Universitario, Escuela de Medicina, Hospital Italiano de Buenos Aires, Buenos Aires, Argentina
Rheumatology Unit, Internal Medical Services, Hospital Italiano de Buenos Aires, Buenos Aires, Argentina


There are differences in the epidemiology of autoimmune diseases in different countries. Studies regarding the epidemiology of systemic lupus erythematosus (SLE) are lacking in Argentina. The purpose of this study was to estimate the incidence and prevalence of SLE in a University Hospital based Health Management Organization in Buenos Aires (HIMCP).


Population: For incidence calculation the population at risk was all adult members of the IHMCP (>18 years old), with continuous affiliation for at least one year from January 1998 to January 2009. Each person was followed until he/she voluntarily left the IHMCP, death or finalization of the study (final dates) contributing time at risk since January 1998 or enrollment date (whichever occurred later) to that final date. Case ascertainment: multiple methods for case finding were used to ensure complete ascertainment: a) patients with the problem SLE, undifferentiated autoimmune disease or mixed connective tissue disease in the IHMCP problem oriented Computer-based Patient Record System, b) patients with positive Antinuclear antibody test (ANA titule>1/160) and/or positive anti-sm antibodies and/ or anti dsDNA antibodies in the Hospital laboratory database, and c) patients who consumed hydroxichloroquine, chloroquine, azathioprine, cyclophosphamide, mycophenolate mofetil, cyclosporine, and or rituximab, from the administrative IHMCP drugs database. Medical records of all patients found were reviewed, and only patients fulfilling ACR criteria for SLE were included. Statistical analysis: Global and by gender incidence rate (IR) was calculated with 95% confidence intervals (CI). Prevalence was estimated at 1/1/ 2009, and the denominator population was the number of active members > 18 years at that date (n= 127,959).


In the study period 186,086 persons contributed a total of 1,082,817.6 person-years, of whom 68 developed SLE: IR: 6.28 (CI: 4.9 – 7.7) cases per 100,000 person-years. There were 57 females: IR: 8.95 (CI: 6.6 – 11.2) cases per 100,000 person-years; and 11 males: IR: 2.55 (CI: 1.2 – 3.9) cases per 100,000 person-years. On January 1/ 2009, 75 prevalent cases were identified: prevalence: 58.6 (CI: 46.1 – 73.5) cases per 100,000 inhabitants (females: 83.2 (CI: 63.9 – 106.4) and males: 23 (CI: 11.9 – 40.1) per 100,000 members).


This is the first report of incidence and prevalence of SLE in Argentina. Incidence and prevalence rates were similar to those from large series in Europe and lower than in other Latin American countries, perhaps reflecting the mainly European origin of this population in Buenos Aires. As expected incidence and prevalence of SLE was higher in females.

To cite this abstract, please use the following information:
Valeiras, Soledad M., Marchese, Martin F., Talani, Alejandro S., Avellaneda, Nicolas L., Etchepare, Alvaro, Etchepare, Patricio, et al; Incidence and Prevalence of Systemic Lupus Erythematosus in Buenos Aires, Argentina: A 11 Years Health Management Organization Based Study. [abstract]. Arthritis Rheum 2011;63 Suppl 10 :1401

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