Efficacy and safety of low-dose tetracycline, amoxicillin quadruple therapy in Helicobacter pylori infection: A retrospective single center study

Table 1 Demographic and clinical data of patients

Variables	500 mg bid (n = 73)	500 mg tid (n = 74)	750 mg bid (n = 71)	P value
Age, mean ± SD	49.2 ± 12.0	50.2 ± 13.9	46.6 ± 15.8	0.348
Age range (years)	20-72	23-72	22-77
Age, ≤ 50 years	36	35	40	0.523
Sex, male/female	41/32	39/35	40/31	0.899
Family history of gastric cancer	1	2	1	1.000
NSAIDS	2	3	0	0.375
Probiotics	7	2	3	0.202
Smoking	15	16	15	1.000
Alcohol drinking	10	14	13	0.689
Hypertension	17	17	15	0.958
Diabetes	5	6	3	0.694
Hyperlipidemia	1	3	1	0.623
Endoscopy diagnosis				0.600
Gastritis	49	42	36
Ulcer	14	7	9
Unknown	10	25	26
Intestinal metaplasia				0.325
No	40	27	22
Yes	23	22	23
Unknown	10	25	26
Treatment times				< 0.001
1	60	42	16
2	8	27	39
≥ 3	5	5	16
Rescue therapy1	13	32	55
PPI				< 0.001
Omeprazole	2	5	27
Rabeprazole	66	63	37
Pantoprazole	1	5	1
Vonoprazan	4	1	6
Bismuth				< 0.001
Bismuth potassium citrate	4	27	37
Colloidal bismuth pectin	69	47	34

¹Rescue therapy was defined as patients who had received eradication therapy once or more but failed.

P values were from two-sided comparisons of the differences between the three groups. 500 mg bid: Tetracycline twice daily; 500 mg tid: Tetracycline three times daily; 750 mg bid: Tetracycline twice daily; NSAIDS: Nonsteroidal anti-inflammatory drugs; PPI: Proton pump inhibitor.

Table 2 Treatment times of patients and the eradication rates

	Eradication rate			P value
	500 mg bid (n = 73)	500 mg tid (n = 74)	750 mg bid (n = 71)
All	65, 89.0%	61, 82.4%	56, 78.9%	0.25
Primary therapy	54/60, 90.0%	37/42, 88.1%	14/16, 87.5%	0.85
1 prior therapy	8/8, 100%	22/27, 81.5%	27/39, 69.2%
≥ 2 prior therapies	3/5, 60.0%	2/5, 40.0%	15/16, 93.8%
Rescue therapy1	11/13, 84.6%	24/32, 75.0%	42/55 76.4%	0.89

¹Rescue therapy was defined as patients who had received eradication therapy once or more but failed.

P values were from two-sided comparisons of the differences between the three groups. 500 mg bid: Tetracycline twice daily; 500 mg tid: Tetracycline three times daily; 750 mg bid: Tetracycline twice daily.

Table 3 Adverse events in the different treatment groups

Adverse effect	All	500 mg bid (n = 73)	500 mg tid (n = 74)	750 mg bid (n = 71)	P value
Total, n/N (%)1	22.5 (49/218)	12.3 (9/73)	31.1 (23/74)	23.9 (17/71)	0.023
Taste distortion	1	0	1	0
Belching	1	0	1	0
Loss of appetite	3	0	1	2
Nausea	5	1	3	1
Vomiting	4	1	1	2
Abdominal pain	1	0	1	0
Bloating	3	0	3	0
Diarrhea	3	1	0	2
Skin rash	4	2	1	1
Fever	3	0	1	2
Dizziness	3	1	1	1
Melena	2	0	1	1
Constipation	2	0	1	1
Abdominal discomfort2	14	3	7	4

¹The symptoms of a single adverse event are counted as 1, and a patient may have multiple adverse events.

²Abdominal discomfort, but not specified.

P values were from two-sided comparisons of the differences among the three treatment groups. 500 mg bid: Tetracycline twice daily; 500 mg tid: Tetracycline three times daily; 750 mg bid: Tetracycline twice daily. N: Number of total patients; n: Number of patients with adverse events.