Research ArticleOriginal Article
Open Access

Clinical features and outcomes of patients with myasthenia gravis

Mohammed H. Alanazy
Neurosciences Journal July 2019, 24 (3) 176-184; DOI: https://doi.org/10.17712/nsj.2019.3.20190011

Article Figures & Data

Tables

  • Table 1

    Demographic information, MG-related history, therapy, and outcomes in the most recent follow-up visit in male and female patients.

    VariablesTotal (n=95)Males (n=40)Females (n=55)P-value
    Mean±SD or n(%)
    Current age (years)42.7±17.647.1±19.439.5±15.60.037
    Age at onset (years)35.2±16.940.5±18.131.3±15.00.009
    Disease duration (years)8.0±7.26.6±6.69.0±7.60.10
    Follow-up duration (months)34.7±14.133.7±13.435.4±14.60.55
    History of autoimmune disorder26 (27.4)2 (5.0)24 (43.6)<0.001
    MG type
     Ocular7 (7.4)4 (10.0)3 (5.5)0.45
     Generalized88 (92.6)36 (90.0)52 (94.5)
    Antibody status
     AChR78 (82.1)33 (82.5)45 (81.8)
     MuSK4 (4.2)04 (7.3)0.12
     Double negative13 (13.7)7 (17.5)6 (10.9)
    MG-QOL15R-A, M±SD5.2±6.04.4±5.06.0±6.60.19
    MG-ADL-A, M±SD1.7±2.41.0±1.92.3±2.50.005
    MGCS, M±SD1.6±2.70.8±1.92.2±3.00.005
    MG-MMT, M±SD2.2±4.70.6±1.83.3±5.80.002
    MGFA
     CSR5 (5.3)2 (5.0)3 (5.5)
     PR51 (53.7)29 (72.5)22 (40)
     MGFA I10 (10.5)3 (7.5)7 (12.7)0.004
     MGFA II27 (28.4)6 (15.0)21 (38.2)
     MGFA III2 (2.1)02 (3.6)
    MG crisis21 (22.1)11 (27.5)10 (18.2)0.28
    MG exacerbation37 (38.9)17 (42.5)20 (36.4)0.55
    Refractory MG12 (12.6)3 (7.5)9 (16.4)0.20
    Thymectomy*61 (64.2)21 (52.5)40 (72.7)0.04
    Thymoma10 (10.5)8 (20.0)2 (3.6)0.02
    Thymic hyperplasia30 (31.6)11 (27.5)19 (34.5)0.47
    Therapy at last follow-up†
    Prednisolone77 (81.1)34 (85.0)43 (78.2)0.40
    Pyridostigmine59 (62.1)24 (60.0)35 (36.6)0.72
    Azathioprine45 (47.4)22 (55.0)23 (42.6)0.23
    Mycophenolate14 (14.7)8 (20.0)6 (10.9)0.22
    Maintenance IVIg16 (16.8)4 (10.0)12 (21.8)0.13
    Rituximab11 (11.6)3 (7.5)8 (14.5)0.35
    Previous IVIg51 (53.7)24 (60.0)27 (49.1)0.29
    Previous plasma exchange10 (10.5)6 (15.0)4 (7.3)0.23

    • AchR - acetylcholine receptor antibodies, CSR - complete stable remission, IVIg - intravenous immunoglobulin, M - mean, MG - myasthenia gravis, MG-ADL-A - Arabic version of the MG-activity of daily living scale, MG-MMT - MG-manual muscle test score, MGCS - MG composite score, MGFA - MG foundation of America classification, MGFA I - ocular MG, MGFA II - mild generalized MG, MGFA III - moderate generalized MG, MG-QOL15R-A - Arabic version of the MG quality-of-life revised questionnaire, MuSK - muscle specific tyrosine kinase antibodies, PR - pharmacologic remission, SD - standard deviation. Percentages (%) are derived from the total number of patients in the respective columns. All MG-specific outcome measures were derived from the last follow-up clinic visit.

    • ↵* Histopathology results were normal in 10 patients and missing in 11 patients.

    • ↵† Therapy at last follow-up: represent total number (%) of each therapy use whether single or combined

  • Table 2

    MG therapy combinations at last follow-up.

    MG therapyNumber (%)
    Prednisolone and azathioprine28 (29.5)
    Prednisolone alone19 (20.0)
    Prednisolone and Mycophenolate10 (10.5)
    Pyridostigmine alone8 (8.4)
    Prednisolone, azathioprine and IVIg7 (7.4)
    Azathioprine alone4 (4.2)
    Prednisolone and Rituximab3 (3.2)
    Prednisolone, azathioprine, IVIg and Rituximab3 (3.2)
    Prednisolone, azathioprine and Rituximab2 (2.1)
    Prednisolone, Mycophenolate, IVIg, and Rituximab2 (2.1)
    Prednisolone, Rituximab, and IVIg1 (1.1)
    Prednisolone, Mycophenolate, and IVIg1(1.1)
    Azathioprine, Mycophenolate, and IVIg1 (1.1)
    Prednisolone and IVIg1 (1.1)
    No current therapy5 (5.3)
    ≥ 2 immunosuppressive therapies58 (61.1)

    • MG - myasthenia gravis, IVIg - intravenous immunoglobulin

  • Table 3

    Demographic information, MG-related history, therapy, and outcomes in the most recent follow-up among patients with early and late onset MG.

    VariablesEarly onset MG (<50 years, n=75)Late onset (≥50 years, n=20)P-value
    Mean±SD or n (%)
    Gender0.001
     Male25 (62.5)15 (37.5)
     Female50 (90.9)5 (9.1)
    Disease duration (years)8.3±7.26.9±7.70.45
    Follow-up duration (months)34.7±14.534.7±12.81.00
    History of autoimmune disorder23 (30.7)3 (15.0)0.16
    MG type at last follow-up visit0.16
     Ocular4 (5.3)3 (15.0)
     Generalized71 (94.7)17 (85.0)
     MG-QOL15R-A5.7±6.03.5±5.90.04
     MG-ADL-A1.9±2.41.2±2.30.10
     MGCS1.9±2.80.7±1.70.07
     MG-MMT2.5±5.11.1±2.60.14
    MGFA0.34
     CSR5 (6.7)0
     PR36 (48.0)15 (75.0)
     MGFA I10 (13.3)0
     MGFA II22 (29.3)5 (25.0)
     MGFA III2 (2.7)0
     MG crisis15 (20.0)6 (30.0)0.37
     MG exacerbation28 (37.3)9 (45.0)0.53
     Refractory MG11 (14.7)1 (5.0)0.25
    Therapy at last follow-up
     Prednisolone60 (80.0)17 (85.0)0.76
     Pyridostigmine43 (57.3)16 (80.0)0.06
     Azathioprine33 (44.6)12 (60.0)0.22
     Mycophenolate13 (17.3)1 (5.0)0.17
     Maintenance IVIg12 (16.0)4 (20.0)0.74
     Rituximab11 (14.7)00.06
     Previous IVIg40 (53.3)11 (55.0)0.89
     Previous plasma exchange8 (10.7)2 (10.0)0.93

    • AchR - acetylcholine receptor antibodies, CSR - complete stable remission, IVIg - intravenous immunoglobulin, M - mean, MG - myasthenia gravis, MG-ADL-A - Arabic version of the MG-activity of daily living scale, MG-MMT - MG-manual muscle test score, MGCS - MG composite score, MGFA - MG foundation of America classification, MGFA I - ocular MG, MGFA II - mild generalized MG, MGFA III - moderate generalized MG, MG-QOL15R-A - Arabic version of the MG quality-of-life revised questionnaire, MuSK - muscle specific tyrosine kinase antibodies, PR - pharmacologic remission SD - standard deviation. Percentages (%) are derived from the total number of patients in the respective columns. All MG-specific outcome measures were derived from the last follow-up clinic visit.

  • Table 4

    Demographic information, MG-related history, therapy, and outcomes in the most recent follow-up among patients with seronegative and AchR-positive MG.

    VariablesAchR (n=78)Double seronegative (n=13)Anti-MuSK (n=4)P-value
    Mean±SD or n (%)
    Current age (years)43.4±17.139.7±17.438.5±29.70.69
    Age at onset (years)35.3±16.335.2±16.132.5±32.90.95
    Disease duration (years)8.5±7.45.5±5.26.6±8.20.38
    Follow-up duration (months)36.1±13.427.8±15.429.5±17.50.11
    History of autoimmune disorder22 (28.2)3 (23.1)1 (25.0)0.92
    MG type0.23
     Ocular4 (5.1)2 (15.4)1 (25.0)
     Generalized74 (94.9)11 (84.6)3 (75.0)
    MG-QOL15R-A5.1±5.93.8±5.011.3±8.70.25
    MG-ADL-A1.76±2.40.9±1.43.3±2.20.13
    MGCS1.7±2.81.2±1.71.7±1.50.79
    MG-MMT2.3±5.01.4±1.80.7±1.20.87
    MGFA0.61
     CSR4 (5.1)01 (25.0)
     PR43 (55.1)6 (46.2)2 (50.0)
     MGFA I5 (6.4)5 (38.5)0
     MGFA II24 (30.8)2 (15.4)1 (25.0)
     MGFA III2 (2.6)00
    MG crisis17 (21.8)2 (15.4)2 (50.0)0.35
    MG exacerbation32 (41.0)2 (15.4)3 (75.0)0.07
    Refractory MG10 (12.8)02 (50.0)0.03*
    Thymectomy58 (74.4)2 (15.4)1 (25.0)<0.001†
    Thymoma10 (12.8)001.00
    Thymic hyperplasia28 (35.9)1 (7.7)1 (25.0)1.00
    Therapy at last follow-up
     Prednisolone65 (83.3)9 (69.2)3 (75.0)0.47
     Pyridostigmine52 (66.7)7 (53.8)00.02‡
     Azathioprine38 (49.4)5 (38.5)2 (50.0)0.77
     Mycophenolate14 (17.9)000.17
     Maintenance IVIg15 (19.2)01 (25.0)0.21
     Rituximab9 (11.5)02 (50.0)0.03*
     Previous IVIg45 (57.7)4 (30.8)2 (50.0)0.19
     Previous plasma exchange9 (11.5)01 (25.0)0.29

    • AchR - acetylcholine receptor antibodies, CSR - complete stable remission, IVIg - intravenous immunoglobulin, M - mean, MG - myasthenia gravis, MG-ADL-A - Arabic version of the MG-activity of daily living scale, MG-MMT - MG-manual muscle test score, MGCS - MG composite score, MGFA - MG foundation of America classification, MGFA I - ocular MG, MGFA II - mild generalized MG, MGFA III - moderate generalized MG, MG-QOL15R-A - Arabic version of the MG quality-of-life revised questionnaire, MuSK - muscle specific tyrosine kinase antibodies, PR - pharmacologic remission, SD - standard deviation. Percentages (%) are derived from the total number of patients in the respective columns. All MG-specific outcome measures were derived from the last follow-up clinic visit.

    • ↵* p=0.008 for comparisons between patients who tested positive for MuSK antibodies and double seronegative patients.

    • ↵† p<0.001 for comparisons between patients who tested positive for AchR antibodies and double seronegative patients.

    • ↵‡ p=0.007 for comparisons between patients who tested positive for AchR antibodies and those who tested positive for MuSK antibodies.

  • Table 5

    Demographic information, MG-related history, therapy, and outcomes in the most recent follow-up based on thymectomy status (patients with thymoma and anti-MuSK antibodies were excluded).

    VariablesThymectomy (n=50)*No thymectomy (n=31)P-value
    Mean±SD or n (%)
    Current age (years)37.7±13.350.4±19.70.003
    Age at onset (years)28.6±10.244.6±18.2<0.001
    Disease duration (years)9.9±7.75.7±5.90.002
    Follow-up duration (months)38.3±11.930.5±16.10.05
    MG type0.07
     Ocular1 (2.0)4 (12.9)
     Generalized49 (98.0)27 (87.1)
    MG-QOL15R-A6.1±6.33.6±4.60.08
    MG-ADL-A2.0±2.51.4±2.20.19
    MGCS2.1±3.11.1±2.10.15
    MG-MMT3.2±5.91.0±2.30.12
    MGFA0.23
     CSR4 (8.0)0
     PR21 (42.0)20 (64.5)
     MGFA I5 (10.0)5 (16.1)
     MGFA II18 (36.0)6 (19.4)
     MGFA III2 (4.0)0
    MG crisis11 (22.0)4 (12.9)0.31
    MG exacerbation16 (32.0)12 (38.7)0.54
    Refractory MG9 (18.0)1 (3.2)0.08
    Therapy at last follow-up
     Prednisolone40 (80.0)26 (83.9)0.66
     Pyridostigmine32 (64.0)19 (63.3)0.81
     Azathioprine21 (42.0)18 (58.1)0.19
     Mycophenolate9 (18.0)1 (3.2)0.08
     Maintenance IVIg8 (16.0)5 (16.1)1.00
     Rituximab7 (14.0)00.04
    Previous IVIg28 (56.0)13 (41.9)0.22
    Previous plasma exchange6 (12.0)00.08

    • AchR - acetylcholine receptor antibodies, CSR - complete stable remission, IVIg - intravenous immunoglobulin, M - mean, MG - myasthenia gravis, MG-ADL-A - Arabic version of the MG-activity of daily living scale, MG-MMT - MG-manual muscle test score, MGCS - MG composite score, MGFA - MG foundation of America classification, MGFA I - ocular MG, MGFA II - mild generalized MG, MGFA III - moderate generalized MG, MG-QOL15R-A - Arabic version of the MG quality-of-life revised questionnaire, MuSK - muscle specific tyrosine kinase antibodies, PR - pharmacologic remission, SD - standard deviation. Percentages (%) are derived from the total number of patients in the respective columns. All MG-specific outcome measures were derived from the last follow-up clinic visit.

    • ↵* one of the 4 patients with anti-Musk had thymectomy before knowing Musk status

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