Studying the relationship between clinical features and mental health among late-onset myasthenia gravis patients

Table 1 Comparison between early-onset and late-onset groups

	Total patients (n = 105)	Early-onset (n = 63)	Late-onset (n = 42)	P value
Gender (n, %)1
Male	49 (46.67)	26 (41.27)	23 (54.76)
Female	56 (53.34)	37 (58.73)	19 (45.24)	0.231
Marital status (n, %)2
Married	63 (60.0)	33 (52.38)	30 (71.43)	0.067
Single (unmarried/divorced/widowed)	42 (40.0)	30 (47.62)	12 (28.57)
Education (n, %)2
Primary school and below	26 (24.76)	12 (19.05)	14 (33.33)	0.073
Secondary school	44 (41.90)	25 (39.68)	19 (45.24)
College and above	35 (33.33)	26 (41.27)	9 (21.43)
Career change due to illness (n, %)2				0.955
No change	69 (65.71)	41 (65.08)	28 (66.67)
Leave of absence	24 (22.86)	15 (23.81)	9 (21.43)
Transfer/unemployment	12 (11.43)	7 (11.11)	5 (11.90)
BMI (kg/m2)3	21.71 (5.77)	20.51 (4.21)	24.36 (4.53)	< 0.001c
Disease duration (mo)3	5.00(12.21)	7.00(13.34)	4.00(8.50)	0.016a
MGFA classification at evaluating (n, %)1
Ⅰ	28 (26.67)	21 (33.33)	7 (16.67)
Ⅱ	40 (38.10)	22 (34.92)	18 (42.86)
Ⅲ	31 (29.52)	16 (25.40)	15 (35.71)
Ⅳ	6 (5.71)	4 (6.35)	2 (4.76)	0.255
Thymectomy (n, %)2	44 (41.90)	28 (44.44)	16 (38.10)	0.551
Comorbidities (n, %)2	49 (46.67)	32 (50.79)	17 (40.48)	0.299
Inducing factor (n, %)1
Respiratory infection	12 (11.43)	6 (9.52)	6 (14.29)
Overfatigue	3 (2.86)	1 (1.59)	2 (4.76)
No triggers	90 (85.71)	56 (88.89)	34 (80.95)	0.470
Clinical features
Onset symptom
Blepharoptosis (n, %)2	97 (92.38)	59 (93.65)	38 (90.48)	0.711
Dysphagia (n, %)2	50 (47.62)	29 (46.03)	21 (50.00)	0.842
Limb muscle weakness (n, %)2	55 (52.38)	31 (49.21)	24 (57.14)	0.550
Dyspnea (n, %)2	15 (14.29)	5 (7.94)	10 (23.81)	0.043a
Serum antibody (nmol/L) 3
Anti-AChR Ab	9.54 (25.98)	3.11 (17.98)	17.51 (27.45)	0.002b
Anti-MuSK Ab	0 (1.13)	0.31 (2.17)	0 (0)	0.098
Seronegative (n, %)2	16 (15.24)	11 (17.46)	5 (11.90)	0.582
Immunotherapy at evaluating
Glucocorticoids (n, %)2	76 (72.38)	49 (77.78)	27 (64.29)	0.181
Azathioprine (n, %)2	31 (29.52)	19 (30.16)	12 (28.57)	0.861
Tacrolimus (n, %)2	8 (7.62)	3 (4.76)	5 (11.90)	0.262
Leflunomide (n, %)2	22 (20.95)	13 (20.63)	9 (21.43)	0.922
No immunotherapy (n, %)2	53 (50.48)	32 (50.79)	21 (50.00)	0.936
Neuropsychological scales
MGC3	6.00 (6.50)	6.00 (6.00)	7.00 (7.00)	0.103
ADL3	3.00 (3.00)	3.00 (4.00)	3.00 (2.00)	0.960
QOL-153	14.00 (15.00)	12.00 (13.50)	16.00 (20.00)	0.027a
HAM-A3	6.00 (7.00)	5.00 (5.50)	8.50 (7.50)	< 0.001c
HAM-D3	8.00 (7.00)	7.00 (8.00)	10.50 (7.75)	0.018a

¹n (%), Fisher’s exact test.

²n (%), Pearson’s χ² test.

³Median (25%Q, 75%Q), Mann-Whitney U test.

^aP < 0.05.

^bP < 0.01.

^cP < 0.001.

BMI: Body mass index; ADL: Activities of daily living scale; MGC: Myasthenia Gravis Composite scale; MG-QOL-15: Myasthenia Gravis Quality of Life 15 questionnaire; HAM-A: Hamilton Anxiety Rating Scale; HAM-D: Hamilton Depression Rating Scale.

Table 2 Correlation between clinical features and age at onset

Clinical features	Correlation	95%CI	t	P value
Disease duration	-0.59	-0.70, -0.446	-7.370	< 0.001c
BMI	0.41	0.233, 0.555	4.520	< 0.001c
Anti-AChR Ab	0.31	0.128, 0.475	3.335	0.001b
QOL-15	0.32	0.133, 0.479	3.383	0.001b
HAM-A	0.41	0.236, 0.557	4.548	< 0.001c
HAM-D	0.26	0.074, 0.432	2.759	0.007b

^aP < 0.05.

^bP < 0.01.

^cP < 0.001.

BMI: Body mass index; MG-QOL-15: Myasthenia Gravis Quality of Life 15 questionnaire; HAM-A: Hamilton Anxiety Rating Scale; HAM-D: Hamilton Depression Rating Scale.

Table 3 Multivariate logistic model of the clinical determinants of anxiety/depression in myasthenia gravis patients

Variables	Model 1		Model 2
	OR (95%CI)	P value	OR (95%CI)	P value
Anxiety
Gender	0.96 (0.45-2.07)	0.917	0.65 (0.25-1.68)	0.372
Age at onset	1.04 (1.02-1.07)	0.002b	1.02 (0.99-1.05)	0.305
Disease duration	0.93 (0.88-0.98)	0.070	0.97 (0.90-1.04)	0.414
BMI	1.10 (0.99-1.23)	0.075	1.05 (0.92-1.21)	0.485
Anti-AChR Ab	1.02 (1.00-1.05)	0.092	1.02 (0.99-1.05)	0.274
QOL-15	1.10 (1.05-1.16)	< 0.001c	1.10 (1.04-1.15)	< 0.001c
Depression
Gender	0.82 (0.36-1.82)	0.636	0.56 (0.19-1.64)	0.293
Age at onset	1.03 (1.00-1.06)	0.022a	1.03 (0.99-1.06)	0.162
Disease duration	0.98 (0.93-1.03)	0.418	1.06 (0.98-1.15)	0.172
BMI	1.05 (0.93-1.17)	0.440	0.97 (0.83-1.13)	0.678
Anti-AChR Ab	1.10 (0.99-1.04)	0.387	1.01 (0.97-1.05)	0.582
QOL-15	1.19 (1.10-1.28)	< 0.001c	1.20 (1.10-1.30)	< 0.001c

^aP < 0.05.

^bP < 0.01.

^cP < 0.001.

Model 1: Unadjusted; Model 2: Adjusted for possible confounders including gender, age at onset, body mass index, and anti-acetylcholine receptor antibody. BMI: Body mass index; QOL-15: Myasthenia Gravis Quality of Life 15 questionnaire; OR = exp (β).