. 2021 May 5;158(2):539–553. doi: 10.1111/jnc.15360

TABLE 2.

Intergroup comparisons

	Healthy controls			Premanifest HD			Manifest HD			Adjusted for	Group membership	HC vs. PM	PM vs. M
	n	Mean	SD	n	Mean	SD	n	Mean	SD	Adjusted for	p value	p value	p value
Primary outcomes
CSF KYNA log(nM)	20	0.98	0.46	20	0.80	0.50	40	1.29	0.50	Age	0.154	0.910	0.113
CSF KYNA log(nM)	20	0.98	0.46	20	0.80	0.50	40	1.29	0.50	Age and CAG	N/A	N/A	0.253
CSF 3‐HK 1/nM	20	0.35	0.16	20	0.33	0.15	40	0.32	0.12	Age	0.383	0.199	0.231
CSF 3‐HK 1/nM	20	0.35	0.16	20	0.33	0.15	40	0.32	0.12	Age and CAG	N/A	N/A	0.034
CSF QUIN 1/√nM	20	0.23	0.05	20	0.25	0.06	40	0.23	0.05	Age	0.312	0.905	0.206
CSF QUIN 1/√nM	20	0.23	0.05	20	0.25	0.06	40	0.23	0.05	Age and CAG	N/A	N/A	0.156
Secondary outcomes
CSF 3‐HK:KYNA 1/√ratio	20	0.95	0.27	20	0.85	0.24	40	1.05	0.25	Age	0.094	0.371	0.036
CSF 3‐HK:KYNA 1/√ratio	20	0.95	0.27	20	0.85	0.24	40	1.05	0.25	Age and CAG	N/A	N/A	0.007
CSF KYNA:KYN log(ratio)	20	−2.79	0.36	20	−2.87	0.33	40	−2.49	0.33	Age	0.005	0.830	0.007
CSF KYNA:KYN log(ratio)	20	−2.79	0.36	20	−2.87	0.33	40	−2.49	0.33	Age and CAG	N/A	N/A	0.027
CSF 3‐HK:KYN 1/(ratio²)	20	238.82	143.04	20	186.91	109.88	40	209.78	113.86	Age	0.445	0.223	0.629
CSF 3‐HK:KYN 1/(ratio²)	20	238.82	143.04	20	186.91	109.88	40	209.78	113.86	Age and CAG	N/A	N/A	0.109
Exploratory outcomes
CSF TRP μM	20	2.16	0.42	20	2.0	0.45	40	2.05	0.35	Age	0.265	0.980	0.196
CSF TRP μM	20	2.16	0.42	20	2.0	0.45	40	2.05	0.35	Age and CAG	N/A	N/A	0.391
CSF KYN 1/√nM	20	0.15	0.03	20	0.16	0.03	40	0.15	0.02	Age	0.836	0.932	0.682
CSF KYN 1/√nM	20	0.15	0.03	20	0.16	0.03	40	0.15	0.02	Age and CAG	N/A	N/A	0.699
CSF AA log(nM)	20	0.92	0.29	20	0.87	0.37	40	0.94	0.27	Age	0.676	0.682	0.386
CSF AA log(nM)	20	0.92	0.29	20	0.87	0.37	40	0.94	0.27	Age and CAG	N/A	N/A	0.641
Plasma TRP √μM	20	7.11	0.81	20	7.18	0.77	38	7.00	0.51	Age	0.642	0.730	0.368
Plasma TRP √μM	20	7.11	0.81	20	7.18	0.77	38	7.00	0.51	Age and CAG	N/A	N/A	0.517
Plasma KYN log(μM)	20	0.62	0.26	20	0.66	0.24	38	0.60	0.24	Age	0.408	0.453	0.183
Plasma KYN log(μM)	20	0.62	0.26	20	0.66	0.24	38	0.60	0.24	Age and CAG	N/A	N/A	0.058
Plasma KYNA log(nM)	19	4.07	0.33	19	4.13	0.42	32	3.96	0.32	Age	0.201	0.516	0.086
Plasma KYNA log(nM)	19	4.07	0.33	19	4.13	0.42	32	3.96	0.32	Age and CAG	N/A	N/A	0.032
Plasma 3‐HK log(nM)	19	3.67	0.24	20	3.58	0.29	38	3.58	0.29	Age	0.442	0.493	0.664
Plasma 3‐HK log(nM)	19	3.67	0.24	20	3.58	0.29	38	3.58	0.29	Age and CAG	N/A	N/A	0.304
Plasma AA 1/√nM	18	0.36	0.05	16	0.36	0.05	37	0.34	0.06	Age	0.451	0.500	0.710
Plasma AA 1/√nM	18	0.36	0.05	16	0.36	0.05	37	0.34	0.06	Age and CAG	N/A	N/A	0.440
Plasma QUIN log(nM)	20	5.85	0.36	19	5.80	0.42	38	5.74	0.32	Age	0.148	0.722	0.087
Plasma QUIN log(nM)	20	5.85	0.36	19	5.80	0.42	38	5.74	0.32	Age and CAG	N/A	N/A	0.061
Post hoc exploratory outcome
CSF KYN/TRP √ratio	20	4.57	0.59	20	4.43	0.64	40	4.71	0.68	Age	0.968	0.895	0.931
CSF KYN/TRP √ratio	20	4.57	0.59	20	4.43	0.64	40	4.71	0.68	Age and CAG	N/A	N/A	0.752

Note that for outcomes where a transformation includes a reciprocal (i.e., 1/x), an increase in the raw measurement corresponds to a decrease in the transformed value and vice‐versa. Bold values are p values smaller than 0.05.

3‐HK, 3‐hydroxykynurenine; AA, anthranilic acid; CSF, cerebrospinal fluid; HC, healthy controls; KYN, kynurenine; KYNA, kynurenic acid; M, manifest HD; N/A, not applicable; PM, premanifest HD; QUIN, quinolinic acid; SD, standard deviation; TRP, tryptophan.