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. 1998 Jan;64(1):78–83. doi: 10.1136/jnnp.64.1.78

Mortality and survival in myasthenia gravis: a Danish population based study

P Christensen 1, T Jensen 1, I Tsiropoulos 1, T Sorensen 1, M Kjar 1, E Hojer-Pedersen 1, M Rasmussen 1, E Lehfeldt 1
PMCID: PMC2169901  PMID: 9436732

Abstract

OBJECTIVES—To study mortality and survival of patients with myasthenia gravis.
METHODS—290 patients with myasthenia gravis were studied, including 212 incident cases identified during a comprehensive epidemiological study of myasthenia gravis in western Denmark 1975-89. Follow up was performed on 31 December 1994. Survival curves were constructed using the life table method. Patient data were compared with data from the public Danish population statistics. Death certificates were provided from the National Registry of Death.
RESULTS—The annual average crude mortality rate was 1.8 per million (range 1.5-2.2). The myasthenia gravis related mortality rate (myasthenia gravis as underlying or contributory cause) was 1.4per million (range 1.1-1.8). The age specific mortality rates were low below 50 years. After this age the mortality increased with age in both sexes; after 60 years more rapidly in men than in women. The overall survival rates three, five, 10, and 20 years from diagnosis were 85%, 81%, 69%, and 63% respectively. The survival of both sexes was shorter than that of the corresponding Danish population. Old age at diagnosis, a classification in Osserman-Genkins group IIB or III, and the presence of a thymoma were associated with a less favourable prognosis. The three, five, 10, and 20year survival rates of thymectomised patients were 94%, 94%, 86%, and 79% respectively. The corresponding figures for the non-thymectomised patients were 78%, 71%, 56%, and 51%. A Cox regression analysis showed that this apparently significant effect of thymectomy was because the thymectomised patients were younger than the non-thymectomised patients. Furthermore, at the time of diagnosis of myasthenia gravis the non-thymectomised patients had a higher frequency of serious conditions associated with myasthenia gravis than the thymectomised patients.
CONCLUSION—Patients with myasthenia gravis generally have a relative good prognosis although their survival is shorter than that of the corresponding population. Old age, a classification in Osserman-Genkins group III, and the presence of a thymoma are associated with a less favourable prognosis. In this study, the apparently significant effect of thymectomy was because the thymectomised patients were younger than non-thymectomised patients and because the non-thymctomised patients had a higher frequency of serious conditions associated with myasthenia gravis.



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Selected References

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  1. Christensen P. B., Jensen T. S., Tsiropoulos I., Sørensen T., Kjaer M., Højer-Pedersen E., Rasmussen M. J., Lehfeldt E., de Fine Olivarius B. Incidence and prevalence of myasthenia gravis in western Denmark: 1975 to 1989. Neurology. 1993 Sep;43(9):1779–1783. doi: 10.1212/wnl.43.9.1779. [DOI] [PubMed] [Google Scholar]
  2. Donaldson D. H., Ansher M., Horan S., Rutherford R. B., Ringel S. P. The relationship of age to outcome in myasthenia gravis. Neurology. 1990 May;40(5):786–790. doi: 10.1212/wnl.40.5.786. [DOI] [PubMed] [Google Scholar]
  3. Drachman D. B. Myasthenia gravis. N Engl J Med. 1994 Jun 23;330(25):1797–1810. doi: 10.1056/NEJM199406233302507. [DOI] [PubMed] [Google Scholar]
  4. Engel A. G. Myasthenia gravis and myasthenic syndromes. Ann Neurol. 1984 Nov;16(5):519–534. doi: 10.1002/ana.410160502. [DOI] [PubMed] [Google Scholar]
  5. Evoli A., Batocchi A. P., Provenzano C., Ricci E., Tonali P. Thymectomy in the treatment of myasthenia gravis: report of 247 patients. J Neurol. 1988 May;235(5):272–276. doi: 10.1007/BF00314173. [DOI] [PubMed] [Google Scholar]
  6. Giagheddu M., Puggioni G., Sanna G., Tamburini G., Marrosu F., Rachele M. G., Murgia B., Rosati G. Epidemiological study of myasthenia gravis in Sardinia, Italy (1958-1986). Acta Neurol Scand. 1989 Apr;79(4):326–333. doi: 10.1111/j.1600-0404.1989.tb03793.x. [DOI] [PubMed] [Google Scholar]
  7. Grob D., Arsura E. L., Brunner N. G., Namba T. The course of myasthenia gravis and therapies affecting outcome. Ann N Y Acad Sci. 1987;505:472–499. doi: 10.1111/j.1749-6632.1987.tb51317.x. [DOI] [PubMed] [Google Scholar]
  8. Gudmundsson K. R. The prevalence of some neurological diseases in Iceland. Acta Neurol Scand. 1968;44(1):57–69. doi: 10.1111/j.1600-0404.1968.tb07443.x. [DOI] [PubMed] [Google Scholar]
  9. Hokkanen E. Epidemiology of myasthenia gravis in Finland. J Neurol Sci. 1969 Nov-Dec;9(3):463–478. doi: 10.1016/0022-510x(69)90090-2. [DOI] [PubMed] [Google Scholar]
  10. Johns T. R. Long-term corticosteroid treatment of myasthenia gravis. Ann N Y Acad Sci. 1987;505:568–583. doi: 10.1111/j.1749-6632.1987.tb51325.x. [DOI] [PubMed] [Google Scholar]
  11. Kurtzke J. F. Epidemiology of myasthenia gravis. Adv Neurol. 1978;19:545–566. [PubMed] [Google Scholar]
  12. Oosterhuis H. J. The natural course of myasthenia gravis: a long term follow up study. J Neurol Neurosurg Psychiatry. 1989 Oct;52(10):1121–1127. doi: 10.1136/jnnp.52.10.1121. [DOI] [PMC free article] [PubMed] [Google Scholar]
  13. Osserman K. E., Genkins G. Studies in myasthenia gravis: review of a twenty-year experience in over 1200 patients. Mt Sinai J Med. 1971 Nov-Dec;38(6):497–537. [PubMed] [Google Scholar]
  14. Perlo V. P., Poskanzer D. C., Schwab R. S., Viets H. R., Osserman K. E., Genkins G. Myasthenia gravis: evaluation of treatment in 1,355 patients. Neurology. 1966 May;16(5):431–439. doi: 10.1212/wnl.16.5.431. [DOI] [PubMed] [Google Scholar]
  15. Peto R., Pike M. C., Armitage P., Breslow N. E., Cox D. R., Howard S. V., Mantel N., McPherson K., Peto J., Smith P. G. Design and analysis of randomized clinical trials requiring prolonged observation of each patient. II. analysis and examples. Br J Cancer. 1977 Jan;35(1):1–39. doi: 10.1038/bjc.1977.1. [DOI] [PMC free article] [PubMed] [Google Scholar]
  16. Phillips L. H., 2nd, Torner J. C., Anderson M. S., Cox G. M. The epidemiology of myasthenia gravis in central and western Virginia. Neurology. 1992 Oct;42(10):1888–1893. doi: 10.1212/wnl.42.10.1888. [DOI] [PubMed] [Google Scholar]
  17. Somnier F. E., Keiding N., Paulson O. B. Epidemiology of myasthenia gravis in Denmark. A longitudinal and comprehensive population survey. Arch Neurol. 1991 Jul;48(7):733–739. doi: 10.1001/archneur.1991.00530190081019. [DOI] [PubMed] [Google Scholar]
  18. Storm-Mathisen A. Epidemiology of myasthenia gravis in Norway. Acta Neurol Scand. 1984 Oct;70(4):274–284. doi: 10.1111/j.1600-0404.1984.tb00825.x. [DOI] [PubMed] [Google Scholar]

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