Plasma levels of IL-6 in patients with untreated major depressive disorder: comparison with catecholamine metabolites

Figures & data

Table 1 Demographic data of the MDD patients and healthy controls

	MDD	Controls
Number	148	40
M/F	65/83	23/17
Age (years), mean (SD)	49.5 (12.1)	44.0 (10.5)
Episode (single/recurrent)	57/91
Melancholic/non-melancholic	47/101
With/without psychotic features	34/114
Duration of illness at the episode (months)	2.3 (1.2)
smoking/non-smoking	69/79	8/32
continuous alcohol use (yes/no)	41/107	7/33

Abbreviations: F, female; M, male; MDD, major depressive disorder.

Table 2 Relations between HAM-DI7 sub-items scores and IL-6, MHPG, or HVA

	Core	Sleep	Activity	Psychic anxiety	Somatic anxiety
MHPG	0.9039	0.5194	0.9676	0.3964	0.326
HVA	0.5527	0.4481	0.5359	0.2944	0.0504
IL-6	<0.00001	<0.00001	<0.00001	<0.00001	<0.00001

Abbreviations: HAM-DI7, 17-item Hamilton Depression Rating Scale; HVA, homovanillic acid; MHPG, 3-methoxy-4-hydroxyphenylglycol.

Table 3 Comparison of IL-6 between the MDD patients and HC

	MDD	SD	Min	Max	HC	SD	Min	Max	t-test	Mean difference	95% CI	Cohen’s d
										Mean	Mean	P-value
IL-6	3.12	1.04	2.95	3.29	2.7	0.831	2.43	2.96	0.0192	0.419	0.0692-0.770	0.45

Abbreviations: MDD, major depressive disorder; Hc, healthy controls.

Table 4 The raw correlations among the biological measures

	Estimated value	Standard error	T-value	P-value	Standard beta
IL-6	1.664207	0.198104	8.4	P<0.0000l	0.573533
MHPG	0.0162167	0.093842	0.17	0.863	0.011857
HVA	0.0023559	0.133953	0.02	0.986	0.001207

Abbreviations: HVA, homovanillic acid; MHPG, 3-methoxy-4-hydroxyphenylglycol.

Table 5 The adjusted correlations among the biological measures

	Standard error	T-value	P-value	Standard beta
IL-6	0.200328	8.52	<0.00001	0.588139
MHPG	0.095001	0.15	0.882	0.010331
HVA	0.134012	0.03	0.9749	0.002165
Age	0.016002	–1.43	0.1554	–0.09866
Gender	0.417227	–0.14	0.8881	–0.00975

Abbreviations: HVA, homovanillic acid; MHPG, 3-methoxy-4-hydroxyphenylglycol.

Table 6 Calculated power for three biomarkers

IL-6
α	σ	δ	Number	Power
0.05	2.48562	1.740565	148	1
MHPG
α	σ	δ	Number	Power
0.05	2.48562	0.03039	148	0.0525
HVA
α	σ	δ	Number	Power
0.05	2.48562	0.006442	148	0.0501

Abbreviations: HVA, homovanillic acid; MHPG, 3-methoxy-4-hydroxyphenylglycol.

Figure 1 Dot plot of IL-6 between MDD and HC (P=0.00096).

Abbreviations: MDD, major depressive disorder; HC, healthy controls.

Figure 2 Partial regression residual leverage plot of plasma IL-6 levels and HAM-D17 scores (P<0.0001, R²=0.33).

Abbreviation: HAM-D17, 17-item Hamilton Depression Rating Scale.

Figure 3 Partial regression residual leverage plot of plasma MHPGlevels and HAM-D17 scores (P=0.8630).

Abbreviations: HAM-D17, 17-item Hamilton Depression Rating Scale; MHPG, 3-methoxy-4-hydroxyphenylglycol.

Figure 4 Partial regression residual leverage plot of plasma HVAlevels and HAM-D17 scores (P=0.9860).

Abbreviations: HAM-D17, 17-item Hamilton Depression Rating Scale; HVA, homovanillic acid.

Hamon M, Blier P. Monoamine neurocircuitry in depression and strategies for new treatments. Prog Neuropsychopharmacol Biol Psychiatry. 2013;45:54–63.23602950

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