Table 1.

Serum creatine kinase (CK) levels of patients in different gender and site of onset.

	Subgroups	n	Median CK (quartile, range), U/L	p-Value
Overall		185	160 (160, 20–2,574)
By gender	Male	107	204 (169, 20–2,574)	<0.001
	Female	78	117 (111, 25–858)
By site of onset	Upper limb	64	171 (152, 30–2,574)	<0.001
	Lower limb	80	197 (146, 32–1,153)
	Bulbar	33	92 (43, 25–376)