Aberrations of biochemical indicators in amyotrophic lateral sclerosis: a systematic review and meta-analysis

Table 1 Summary of comparative outcomes for measurements of biochemical indicators in blood and CSF

Biochemical indicator	No. of studies	No. of ALS/controls*	Main effect					Heterogeneity			Publication bias
Biochemical indicator	No. of studies	No. of ALS/controls*	WMD	Lower 95%CI	High 95% CI	z score	p value	df	p value	I² statistic	Egger intercept	p value
Total cholesterol	17	2801/4545	4.44	−2.62	11.50	1.23	0.22	21	< 0.001	89.40%	1.42	0.23
LDL-C	13	2677/4347	0.46	−6.56	7.47	0.13	0.90	16	< 0.001	95.10%	0.24	0.88
HDL-C	14	2707/4376	1.67	−0.89	4.24	1.28	0.20	17	< 0.001	86.70%	2.57	0.02
TG	11	2366/2261	0.11	−9.15	9.37	0.02	0.98	12	< 0.001	83.90%	−2.13	0.05
Fasting blood glucose	9	301/241	0.13	0.06	0.21	3.38	0.001	9	0.39	5.60%	0.51	0.35
Fasting insulin	6	94/88	−6.79	−29.27	15.70	0.59	0.55	6	< 0.001	89.70%	2.19	0.59
CSF glucose	3	132/91	0.04	−0.10	0.18	0.54	0.59	2	0.18	41.50%	1.91	0.56
CSF total protein	6	417/165	−1.53	−5.19	2.12	1.31	0.19	4	0.64	0.00%	−0.11	0.89
Qalb	7	627/212	0.44	−0.51	1.39	0.91	0.36	6	0.001	72.20%	−0.47	0.72
Serum albumin	3	630/611	−1.52	−5.53	2.48	0.74	0.46	2	< 0.001	94.80%	5.37	0.002
Serum total protein	3	705/690	−0.44	−1.03	0.14	1.49	0.14	2	< 0.001	98.80%	15.64	0.25
Serum ferritin	9	1661/1219	63.42	48.12	78.73	8.12	< 0.001	15	0.001	67.60%	1.89	0.06
Serum transferrin	7	1163/718	0.07	−0.58	0.72	0.21	0.83	10	< 0.001	99.60%	−0.41	0.96
Serum iron	6	974/659	0.34	−0.68	1.36	0.66	0.51	7	0.012	61.10%	−2.18	0.15
TIBC	3	236/304	−2.42	−3.93	−0.90	3.12	0.002	3	0.29	19.60%	0.05	0.99
TSC %	3	858/486	2.79	1.52	4.05	4.33	< 0.001	3	0.96	0	1.02	0.35
Creatine kinase	5	229/1843	80.29	32.90	127.67	3.32	0.001	6	< 0.001	93.20%	5.51	0.27

Abbreviations: ALS amyotrophic lateral sclerosis, CSF cerebrospinal fluid, df degrees of freedom, HDL-C high-density lipoprotein cholesterol, LDL-C low-density lipoprotein cholesterol, NA not available, Qalb CSF/serum albumin quotient, TC total cholesterol, TG triglyceride, TIBC total iron binding capacity, TSC transferrin saturation coefficient, WMD weighted mean difference. * controls include healthy controls and other neurological diseases controls