Early postoperative negative conversion of Helicobacter pylori stool antigen after distal gastrectomy and potential host-related factors

Table 1 Baseline clinicopathological characteristics of the overall cohort according to preoperative Helicobacter pylori infection status, n (%)/mean ± SD

Variables	Total (n = 129)	Preoperative status of helicobacter infection		P value
		No active infection	Active infection
Overall	129 (100.0)	76 (58.9)	53 (41.1)
Age (years)	65.0 ± 11.9	66.8 ± 11.7	62.4 ± 11.7	0.036
Sex				0.634
Male	92 (71.3)	53 (69.7)	39 (73.6)
Female	37 (28.7)	23 (30.3)	14 (26.4)
Body mass index (kg/m2)	24.7 ± 3.3	24.8 ± 3.3	24.5 ± 3.3	0.652
American Society of Anesthesiologists score	2.08 ± 0.65	2.13 ± 0.66	2.00 ± 0.65	0.264
Tumor depth (EGC vs AGC)				0.834
EGC	106 (82.2)	62 (81.6)	44 (83.0)
AGC	23 (17.8)	14 (18.4)	9 (17.0)
Nodal status				0.3031
Negative	111 (86.0)	63 (82.9)	48 (90.6)
Positive	18 (14.0)	13 (17.1)	5 (9.4)
Clavien-Dindo Grade				0.453
0-I	103 (79.8)	59 (77.6)	44 (83.0)
≥ II	26 (20.2)	17 (22.4)	9 (17.0)
Use of proton pump inhibitors				0.486
Negative	120 (93.0)	72 (94.7)	48 (90.6)
Positive	9 (7.0)	4 (5.3)	5 (9.4)
Postoperative antibiotics use				0.565
Negative	104 (80.6)	60 (78.9)	44 (83.0)
Positive	25 (19.4)	16 (21.1)	9 (17.0)
Serum helicobacter immunoglobulin G				< 0.001
Negative (%)	25 (19.4)	24 (31.6)	1 (1.9)
Positive (%)	104 (80.6)	52 (68.4)	52 (98.1)

¹Fisher’s exact test, or Welch’s t-test as appropriate.

Comparisons between groups were performed using χ² test. AGC: Advanced gastric cancer; EGC: Early gastric cancer.

Table 2 Comparison between persistent infection and early negative conversion groups, n (%)/mean ± SD

Variable	Total (n = 53)	Persistent (n = 13)	Negative conversion (n = 40)	P value
Age (years)	62.4 ± 11.7	61.5 ± 9.9	62.7 ± 12.4	0.711
Sex, male	39 (73.6)	8 (61.5)	31 (77.5)	0.292
Body mass index (kg/m2)	24.5 ± 3.3	24.3 ± 3.9	24.6 ± 3.1	0.809
American Society of Anesthesiologists score (continuous)	2.0 ± 0.7	1.7 ± 0.5	2.1 ± 0.7	0.024
Diabetes mellitus	15 (28.3)	1 (7.7)	14 (35.0)	0.08
Hypertension	17 (32.1)	2 (15.4)	15 (37.5)	0.183
Chronic kidney disease	2 (3.8)	0 (0.0)	2 (5.0)	1
Serum albumin (g/dL)	4.2 ± 0.4	4.2 ± 0.5	4.2 ± 0.4	0.804
Hemoglobin (g/dL)	13.2 ± 2.0	13.8 ± 1.5	13.0 ± 2.1	0.168
Follow-up time (days after surgery)	110.8 ± 19.4	106.5 ± 7.8	112.2 ± 21.8	0.169
Postoperative proton pump inhibitor use	2 (3.8)	0 (0.0)	2 (5.0)	1
Postoperative antibiotics use	8 (15.1)	1 (7.7)	7 (17.5)	0.662
Operation time (minutes)	165.8 ± 50.3	169.6 ± 41.8	164.5 ± 53.2	0.724
Estimated blood loss (mL)	97.2 ± 74.0	75.1 ± 29.7	104.5 ± 82.6	0.063
Postoperative complications (Clavien-Dindo ≥ II)	9 (17.0)	1 (7.7)	8 (20.0)	0.424

Continuous variables compared using Welch’s t test. Categorical variables compared using Fisher’s exact test.

Table 3 Primary multivariable logistic regression for early negative conversion (maximum likelihood estimation vs Firth)

Variable	MLE OR (95%CI)	MLE P value	Firth OR (95%CI)	Firth P value
American Society of Anesthesiologists score (per 1-point increase)	3.02 (0.91-10.01)	0.071	2.55 (0.83-7.85)	0.104
Age (per 1-year increase)	1.02 (0.96-1.07)	0.592	1.01 (0.96-1.07)	0.629
Body mass index (per 1 kg/m2 increase)	1.09 (0.87-1.36)	0.46	1.07 (0.87-1.33)	0.507
Sex (female vs male)	0.48 (0.11-2.03)	0.319	0.51 (0.13-2.07)	0.346
Postoperative antibiotics use (yes vs no)	1.85 (0.19-18.07)	0.596	1.46 (0.19-11.01)	0.716

Firth: Firth penalized logistic regression (sensitivity analysis to reduce small-sample bias); MLE: Maximum likelihood estimation; OR: Odds ratio.