Table 4.

MANCOVA: plasma content of tryptophan (TRP), kynurenine (KYN), and kynurenic acid (KYNA), controlling for eGFR and BMI (grouping factor: use of ACE inhibitors).

Multivariate Tests
		Wilks’ Lambda **	F	df 1	df 2	p	η2p
eGFR		0.76	4.07	3	38	* 0.01	0.24
BMI		0.98	0.29	3	38	0.83	0.02
Use of ACEi		0.78	3.57	3	38	* 0.02	0.22
Univariate Tests
	DV	Type III SS	df	MS	F	p	η2p
eGFR ***	[TRP]	3.32 × 106	1	3.32 × 106	0.07	0.80	<0.01
	[KYN]	8.81 × 106	1	8.81 × 106	3.03	0.09	0.07
	[KYNA]	822.95	1	822.95	6.06	* 0.02	0.13
BMI	[TRP]	1.39 × 106	1	1.39 × 106	0.03	0.87	<0.01
	[KYN]	1.41 × 106	1	1.41 × 106	0.48	0.49	0.01
	[KYNA]	0.04	1	0.04	0.00	0.99	<0.01
Use of ACEi	[TRP]	4.75 × 107	1	4.75 × 107	0.97	0.33	0.02
	[KYN]	19,159.33	1	19,159.33	0.01	0.94	0.00
	[KYNA]	762.73	1	762.73	5.62	* 0.02	0.12
Residuals	[TRP]	1.95 × 109	40	4.87 × 107
	[KYN]	1.16 × 108	40	2.91 × 106
	[KYNA]	5430.12	40	135.75

Two-tailed p-values (p ≤ 0.05) are flagged (*). Values of all metabolites are in nM (nanomoles). ** Since the Box’s M test of equality of covariances was not significant (p = 0.05), we used Wilks’ Lambda as test statistics to express the results of the multivariate test. *** eGFR calculated using the 2021 adapted version of CKD-EPI (Chronic Kidney Disease Epidemiology Collaboration) equation, adjusted for sex, age, and serum creatinine (The National Kidney Foundation: https://www.kidney.org/professionals/kdoqi/gfr_calculator/formula; accessed on 16 July 2023). Abbreviations: F = F-test value; p = p-value; DV = dependent variable; SS = sum of Squares; df = degrees of freedom; MS = mean square; η²_p = partial eta-squared (effect size); ACEi = angiotensin-converting-enzyme inhibitors; BMI = body-mass-index; eGFR = glomerular filtration rate; KYN = kynurenine; KYNA = kynurenic acid; TRP = tryptophan.