New fecal test for non-invasive Helicobacter pylori detection: A diagnostic accuracy study

Table 1 Characteristics of the participants included in the study n (%)

Characteristic	Value (n= 294)
Age, median (IQR), yr	37.0 (29.0-46.0)
Female sex, number	177 (60.2)
Helicobacter pylori infection, number	95 (32.3)1
Upper endoscopy with histology, number	23 (7.8)2
Dyspeptic symptoms, number
Post-prandial fullness	115 (39.1)
Early satiation	50 (17.0)
Epigastric pain	130 (44.2)
Epigastric burning	170 (57.8)
Concomitant diseases, number
Cardiovascular disease	8 (2.7)
Chronic kidney disease/dialysis	0 (0)
Chronic liver disease/cirrhosis	3 (1.0)
Other chronic diseases3	10 (3.4)

¹Diagnosed with the ¹³C-urea breath test (reference standard test);

²There were 40 participants older than 50 years, but 17 refused to undergo upper endoscopy;

³Including asthma (8 participants), spasmophilia (1 participant), multiple sclerosis (1 participant). IQR: Interquartile range.

Table 2 Direct comparisons between the ¹³C-urea breath test and THD fecal test results for detecting participants with Helicobacter pylori infection

	13C-urea breath test
	Positive	Negative
THD fecal test
Positive	83	3
Negative	9	195
Missing1	3	1
Total	95	199

¹Four participants withdrew from the study after enrollment, thus they underwent the

¹³C-urea breath test but not the THD fecal test.

Table 3 Diagnostic accuracy parameters of the THD fecal test for detecting Helicobacter pylori infection, using ¹³C-urea breath test as the reference standard

Parameter	Complete-case analysis	Best-case analysis	Worst-case analysis
	(n = 290)	(n = 294)1	(n = 294)1
Sensitivity, % (95%CI)	90.2 (84.2 to 96.3)	90.5 (84.6 to 96.4)	87.4 (80.7 to 94.1)
Specificity, % (95%CI)	98.5 (96.8 to 100)	98.5 (96.8 to 100)	98.0 (96.0 to 99.9)
PPV, % (95%CI)	96.5 (92.6 to 100)	96.6 (92.9 to 100)	95.4 (91.0 to 99.8)
NPV, % (95%CI)	95.6 (92.8 to 98.4)	95.6 (92.8 to 98.4)	94.2 (91.0 to 97.4)
Accuracy, % (95%CI)	95.9 (93.6 to 98.2)	95.9 (93.7 to 98.2)	94.6 (92.0 to 97.2)
Positive LR, estimate (95%CI)	59.5 (19.3 to 183.4)	60.0 (19.5 to 185.0)	43.5 (16.4 to 115.0)
Negative LR, estimate (95%CI)	0.10 (0.05 to 0.18)	0.10 (0.05 to 0.18)	0.13 (0.08 to 0.22)

¹The analysis includes four participants with missing data for the THD fecal test. PPV: Positive predictive value; NPV: Negative predictive value; LR: Likelihood ratio; CI: Confidence interval.

Table 4 Helicobacter pylori resistance rates to clarithromycin and levofloxacin in the 83 infected participants identified with the THD fecal test n (%)

	Clarithromycin		Total
	Susceptible	Resistant
Levofloxacin
Susceptible	49 (59.1)	27 (32.5)	76 (91.6)
Resistant	3 (3.6)	4 (4.8)	7 (8.4)
Total	52 (62.7)	31 (37.3)	83 (100)