Background: Different epidemiological studies, especially in Europe, have estimated the incidence density of myasthenia gravis (MG) to range between 1.7 and 21.3/1,000,000/person-year; however, data from regions such as Latin America are scarce. This study is aimed at estimating the incidence and prevalence of acquired MG in Buenos Aires, Argentina. Methods: The study population comprised of affiliates of the Italian Hospital Medical Care Program, a prepaid health maintenance organization located in Buenos Aires. The evaluation method for case detection included a retrospective search from January 1, 2006, through December 31, 2012. Results: Of the 60 cases identified, 36 (60%) were females. The median age at diagnosis was 69 years (IQR 51.5-79). The mean age at diagnosis was 63.3 years (SD ±20). A total of 28 patients (46.7%) had generalized MG and 32 had ocular MG (53.3%). Thirty five patients (58.3%) had acetylcholine receptor antibodies and 2 (3.3%) had muscle-specific receptor tyrosine kinase antibodies. The crude incidence density (ID) of MG was 61.33 per 1,000,000 person-years (95% CI 47.62-79.99). The adjusted ID for the Argentinean population was 38.8 per 1,000,000 person-years (95% CI 27.09-50.51) and for the Buenos Aires population was 47.49 (95% CI 34.73-60.25). Conclusions: The results obtained are similar to those published for other geographical areas.

1.
Meriggioli MN, Sanders DB: Autoimmune myasthenia gravis: emerging clinical and biological heterogeneity. Lancet Neurol 2009;8:475-490.
2.
Hoch W, McConville J, Helms S, Newsom-Davis J, Melms A, Vincent A: Auto-antibodies to the receptor tyrosine kinase MuSK in patients with myasthenia gravis without acetylcholine receptor antibodies. Nat Med 2001;3:365-368.
3.
Higuchi O, Hamuro J, Motomura M, Yamanashi Y: Autoantibodies to low-density lipoprotein receptor-related protein 4 in myasthenia gravis. Ann Neurol 2011;69:418-422.
4.
Somnier FE: Increasing incidence of late-onset anti-AChR antibody-seropositive myasthenia gravis. Neurology 2005;65:928-930.
5.
Emilia-Romagna Study Group on Clinical and Epidemiological Problems in Neurology: Incidence of myasthenia gravis in the Emilia-Romagna region: a prospective multicenter study. Emilia-Romagna Study Group on Clinical and Epidemiological Problems in Neurology. Neurology 1998;51:255-258.
6.
Casetta I, Groppo E, De Gennaro R, Cesnik E, Piccolo L, Volpato S, Granieri E: Myasthenia gravis: a changing pattern of incidence. J Neurol 2010;257:2015-2019.
7.
INDEC o D GdEyC: Censo Nacional de Poblaci ón, Hogares y Vivienda. 2010 http://www.indec.gov.ar/ (November 2011).
8.
Unidad de Informació n, Monitoreo y Evaluació n (UIMyE) o Ministerio de Desarrollo Social: Gobierno de la Ciudad de Buenos Aires. http://www.buenosaires.gob.ar/areas/des_social/evaluacion_programas/sistemas_sis.php?menu_id_23736.
9.
Belló M, Becerril-Montekio VM: Sistema de Salud en Argentina. Salud Publica Mex 2011;53;S96-S108.
10.
Navas H, Lopez Osornio A, Gambarte L, Elías Leguizamón G, Wasserman S, Orrego N, Luna D, de Quirós FG: Implementing rules to improve the quality of concept post-coordination with SNOMED CT. Stud Health Technol Inform 2010;160:1045-1049.
11.
Aragonès JM, Bolíbar I, Bonfill X, Bufill E, Mummany A, Alonso F, Illa I: Myasthenia gravis: a higher than expected incidence in the elderly. Neurology 2003;60:1024-1026.
12.
Alkhawajah NM, Oger J: Late-onset myasthenia gravis: a review when incidence in older adults keeps increasing. Muscle Nerve 2013;48:705-710.
13.
Aarli JA, Romi F, Skeie GO, Gilhus NE: Myasthenia gravis in individuals over 40. Ann N Y Acad Sci 2003;998:424-431.
14.
Gattellaria M, Goumas C, Worthington JM: A national epidemiological study of Myasthenia Gravis in Australia. Eur J Neurol 2012;19:1413-1420.
15.
Andersena JB, Engeland A, Owe JF, Gilhus NE: Myasthenia gravis requiring pyridostigmine treatment in a national population cohort. Eur J Neurol 2010;17:1445-1450.
16.
Pakzad Z, Aziz T, Oger J: Increasing incidence of myasthenia gravis among elderly in British Columbia, Canada. Neurology 2011;76:1526-1528.
17.
Carr AS, Cardwell CR, McCarron PO, McConville J: A systematic review of population based epidemiological studies in Myasthenia Gravis. BMC Neurol 2010;10:46.
18.
Breiner A, Widdifield J, Katzberg HD, Barnett C, Bril V, Tu K: Epidemiology of myasthenia gravis in Ontario, Canada. Neuromuscul Disord 2016;26:41-46.
19.
Chien-Hsu Lai a Hung-Fu Tseng b: Nationwide population-based epidemiological study of Myasthenia Gravis in Taiwan. Neuroepidemiology 2010;35:66-71.
20.
Casetta I, Fallica E, Govoni V, Azzini C, Tola M, Granieri E: Incidence of myasthenia gravis in the province of Ferrara: a community-based study. Neuroepidemiology 2004;23:281-284
21.
Mombaur B, Lesosky MR, Liebenberg L, Vreede H, Heckmann JM: Incidence of acetylcholine receptor-antibody-positive Myasthenia Gravis in South Africa. Muscle Nerve 2015;51:533-537.
Copyright / Drug Dosage / Disclaimer
Copyright: All rights reserved. No part of this publication may be translated into other languages, reproduced or utilized in any form or by any means, electronic or mechanical, including photocopying, recording, microcopying, or by any information storage and retrieval system, without permission in writing from the publisher.
Drug Dosage: The authors and the publisher have exerted every effort to ensure that drug selection and dosage set forth in this text are in accord with current recommendations and practice at the time of publication. However, in view of ongoing research, changes in government regulations, and the constant flow of information relating to drug therapy and drug reactions, the reader is urged to check the package insert for each drug for any changes in indications and dosage and for added warnings and precautions. This is particularly important when the recommended agent is a new and/or infrequently employed drug.
Disclaimer: The statements, opinions and data contained in this publication are solely those of the individual authors and contributors and not of the publishers and the editor(s). The appearance of advertisements or/and product references in the publication is not a warranty, endorsement, or approval of the products or services advertised or of their effectiveness, quality or safety. The publisher and the editor(s) disclaim responsibility for any injury to persons or property resulting from any ideas, methods, instructions or products referred to in the content or advertisements.
You do not currently have access to this content.