Table 4

Single-factor ANOVA of clinical and laboratory variables at enrolment and occurrence of seizures regardless of attribution (95% CI)

Predictor		N^*	Hazard ratio	Lower 95% CI	Higher 95% CI	p Value
Female gender		75	0.48	0.27	0.84	0.010
Race/ethnicity	Caucasian	75				0.036
	Asian		0.47	0.18	1.21
	African		1.70	0.95	3.03
	Hispanic		1.79	0.99	3.23
	Other		1.18	0.36	3.85
Geography	Canada	74				0.307
	USA		1.25	0.63	2.47
	Europe		1.34	0.68	2.64
	Asia		0.81	0.29	2.24
	Mexico		2.01	0.96	4.23
Postsecondary education	No	70	2.15	1.34	3.44	0.002
Age at diagnosis^†	Linear	75	0.83	0.64	1.07	0.050
	Quadratic		1.22	1.04	1.43
SLEDAI-2K score^‡	Linear	26	1.43	0.88	2.32	0.315
	Quadratic		0.94	0.81	1.10
SLEDAI-2K score (w/o NP variables)	Linear	25	1.18	0.72	1.93	0.792
	Quadratic		0.97	0.84	1.14
SLEDAI-2K score (w/o seizure)	Linear	25	1.32	0.80	2.20	0.553
	Quadratic		0.94	0.79	1.12
SDI score		21	1.41	1.05	1.90	0.024
SDI score (w/o NP variables)		20	1.44	1.05	1.99	0.025
SDI score (w/o seizure)		20	1.40	1.03	1.89	0.033
Medications	Corticosteroids	26	6.29	1.41	28.02	0.015
	Antidepressants		0.86	0.26	2.88
	ASA, warfarin		1.69	0.75	3.78
	Anticoagulant
	Antimalarials		0.443	0.20	0.97
	Immunosuppressants		1.23	0.52	2.91
Lupus anticoagulant		51	1.58	0.87	2.89	0.135
Anticardiolipin		50	1.31	0.61	2.78	0.488
Anti-β₂-GPI		50	1.50	0.75	3.01	0.248
Anti-ribosomal P		50	0.58	0.18	1.87	0.364
Anti-NR2		44	0.47	0.15	1.52	0.207

↵* N is the total number of available events (first occurrence of seizures) for analysis.
↵† Age at diagnosis was standardised by taking (age at diagnosis-35)/14.
‡ SLEDAI-2K and SLEDAI-2K (w/o NP variables) were standardised by taking (SLEDAI-2K-4)/4.
ANOVA, analysis of variance; ASA, acetylsalicylic acid; NP, neuropsychiatric; SLEDAI-2K, Systemic Lupus Erythematosus Disease Activity Index 2000.