Systemic immune-inflammation index and postoperative anxiety after transforaminal endoscopic lumbar discectomy

Table 1 Baseline demographic and clinical characteristics of patients in the anxiety and non-anxiety groups, n (%)

Variable	Anxiety group (n = 47)	Non-anxiety group (n = 133)	P value
Age (years)	48.6 ± 11.3	46.9 ± 12.1	0.408
Sex (male/female)	25/22	74/59	0.763
BMI (kg/m2)	24.8 ± 3.2	24.3 ± 3.5	0.392
Smoking status	14 (29.8)	32 (24.1)	0.438
Duration of symptoms (months)	8.4 ± 5.6	6.5 ± 4.8	0.021
Herniation level			0.651
L3/4	3 (6.4)	10 (7.5)
L4/5	26 (55.3)	68 (51.1)
L5/S1	18 (38.3)	55 (41.4)
ASA class (I/II/III)	18/24/5	56/64/13	0.812
Operative time (min)	62.4 ± 15.8	58.7 ± 14.2	0.138
Intraoperative blood loss (mL)	18.3 ± 8.6	16.5 ± 7.9	0.192
Preoperative VAS-back pain	5.8 ± 1.9	5.3 ± 1.7	0.092
Preoperative VAS-leg pain	7.1 ± 1.6	6.4 ± 1.8	0.014
Preoperative ODI (%)	58.6 ± 14.2	52.1 ± 13.8	0.008
Hospital stay (days)	2.8 ± 1.1	2.5 ± 0.9	0.072

BMI: Body mass index; ASA: American Society of Anesthesiologists; ODI: Oswestry Disability Index; VAS: Visual Analog Scale.

Table 2 Comparison of inflammatory and immune markers between anxiety and non-anxiety groups

Variable	Anxiety group (n = 47)	Non-anxiety group (n = 133)	P value
Preoperative SII	412.5 ± 168.3	389.6 ± 152.7	0.396
Postoperative SII	587.4 ± 198.6	423.8 ± 156.3	< 0.001
Preoperative TNF-α (pg/mL)	15.4 ± 6.2	14.1 ± 5.8	0.208
Postoperative TNF-α (pg/mL)	28.6 ± 9.4	21.3 ± 7.8	< 0.001
Preoperative IL-6 (pg/mL)	8.6 ± 4.3	7.9 ± 3.8	0.307
Postoperative IL-6 (pg/mL)	45.8 ± 18.7	29.4 ± 12.6	< 0.001
Preoperative CRP (mg/L)	4.8 ± 3.2	4.2 ± 2.9	0.248
Postoperative CRP (mg/L)	32.4 ± 14.5	19.8 ± 10.3	< 0.001
Preoperative PCT (ng/mL)	0.05 ± 0.03	0.04 ± 0.02	0.312
Postoperative PCT (ng/mL)	0.18 ± 0.09	0.11 ± 0.06	< 0.001
Preoperative RF (IU/mL)	16.8 ± 8.4	13.5 ± 6.9	0.032
Postoperative RF (IU/mL)	17.2 ± 8.1	14.8 ± 7.3	0.058
ANA positive, n (%)	8 (17.0)	16 (12.0)	0.287
Preoperative IgG (g/L)	12.4 ± 2.8	12.8 ± 3.1	0.438
Postoperative IgG (g/L)	11.6 ± 2.5	12.3 ± 2.9	0.068
Preoperative IgA (g/L)	2.3 ± 0.8	2.2 ± 0.7	0.446
Postoperative IgA (g/L)	2.1 ± 0.7	2.2 ± 0.8	0.618
Preoperative IgM (g/L)	1.2 ± 0.4	1.1 ± 0.5	0.226
Postoperative IgM (g/L)	1.1 ± 0.4	1.1 ± 0.4	0.854

SII: Systemic immune-inflammation index; TNF-α: Tumor necrosis factor alpha; IL-6: Interleukin-6; PCT: Procalcitonin; CRP: C-reactive protein; RF: Rheumatoid factor; IgG: Immunoglobulin G; IgA: Immunoglobulin A; IgM: Immunoglobulin M.

Table 3 Univariate and multivariate logistic regression analysis of risk factors for postoperative anxiety

Variable	Univariate OR (95%CI)	P value	Multivariate OR (95%CI)	P value
Duration of symptoms	1.058 (1.004-1.114)	0.034	-	-
Preop VAS-leg pain	1.248 (1.042-1.495)	0.016	-	-
Preop ODI	1.034 (1.009-1.060)	0.009	1.028 (0.998-1.059)	0.068
Postop SII	1.004 (1.002-1.006)	< 0.001	1.003 (1.001-1.005)	0.008
Postop TNF-α	1.098 (1.052-1.146)	< 0.001	-	-
Postop IL-6	1.106 (1.056-1.159)	< 0.001	1.087 (1.021-1.158)	0.009
Postop CRP	1.069 (1.041-1.098)	< 0.001	1.045 (1.012-1.079)	0.007
Postop PCT	1.084 (1.012-1.162)	0.022	-	-
Preop RF	1.048 (1.004-1.094)	0.033	-	-

ODI: Oswestry Disability Index; VAS: Visual Analog Scale; SII: Systemic immune-inflammation index; TNF-α: Tumor necrosis factor alpha; IL-6: Interleukin-6; PCT: Procalcitonin; CRP: C-reactive protein; RF: Rheumatoid factor; OR: Odds ratio; CI: Confidence interval.

Table 4 Receiver operating characteristic curve analysis of independent risk factors for postoperative anxiety

Variable	AUC (95%CI)	Cut off	Sensitivity (%)	Specificity (%)
Postop SII	0.728 (0.647-0.809)	498.5	72.3	66.9
Postop IL-6	0.751 (0.672-0.830)	35.2 pg/mL	68.1	73.7
Postop CRP	0.738 (0.658-0.818)	24.8 mg/L	70.2	69.2
Combined model	0.836 (0.770-0.902)	-	78.7	76.7

SII: Systemic immune-inflammation index; IL-6: Interleukin-6; CRP: C-reactive protein; AUC: Area under the curve; CI: Confidence interval.

Table 5 Spearman’s rank correlation analysis between inflammatory/immune markers and Hospital Anxiety and Depression Scale-Anxiety subscale scores

Variable	Correlation coefficient (r)	P value
Postoperative SII	0.412	< 0.001
Postoperative TNF-α	0.368	< 0.001
Postoperative IL-6	0.445	< 0.001
Postoperative CRP	0.398	< 0.001
Postoperative PCT	0.286	< 0.001
Preoperative RF	0.168	0.024
Postoperative IgG	-0.124	0.097
Postoperative IgA	-0.038	0.614
Postoperative IgM	-0.021	0.782

SII: Systemic immune-inflammation index; TNF-α: Tumor necrosis factor alpha; IL-6: Interleukin-6; PCT: Procalcitonin; CRP: C-reactive protein; RF: Rheumatoid factor; IgG: Immunoglobulin G; IgA: Immunoglobulin A; IgM: Immunoglobulin M.