Corpus-predominant gastritis as a risk factor for false-negative 13C-urea breath test results.
BACKGROUND
Urea breath test sensitivity seems affected by increased intragastric acidity during therapy with antisecretory drugs. Intragastric pH is increased in patients with corpus gastritis with/without atrophy.


OBJECTIVE
To test the hypothesis that urea breath test results may also be affected by this gastritis phenotype.


METHODS
123 untreated patients underwent gastroscopy plus biopsies and intragastric pH measurement. The study included 82 endoscopically proven Helicobacter pylori-positive patients who were offered urea breath test with an acidic meal. Histological findings, urea breath test results and intragastric pH were compared in 66 of the subjects.


RESULTS
21 of 66 (31.8%) patients had a false-negative urea breath test. In these patients corpus-predominant gastritis (85.7% vs. 37.7%; P = 0.0004) and fundic atrophy (66.6% vs. 17.7%; P = 0.0001) were more frequent than in patients with true-positive urea breath test. Intragastric pH was higher in false-negative patients (mean 6.3 vs. 4.4; P = 0.001). In a multivariate analysis, the only risk factor for a false-negative urea breath test was the presence of corpus-predominant gastritis (OR = 5.6; 95% CI: 1.1-27). There was a negative correlation between the intragastric pH and the delta over baseline values (r = -0.378; P = 0.0023).


CONCLUSIONS
Our results support the hypothesis that the pattern of gastritis can affect the sensitivity of urea breath test, and suggest that patients with corpus-predominant gastritis have a high risk of false-negative urea breath test results.
Capurso
G
G
Digestive and Liver Disease Unit, S Andrea Hospital, II Medical School, University La Sapienza, Rome, Italy.
Carnuccio
A
A
Lahner
E
E
Panzuto
F
F
Baccini
F
F
Delle Fave
G
G
Annibale
B
B
D000328:Adult; D000368:Aged; D001944:Breath Tests; D005188:False Negative Reactions; D005260:Female; D005756:Gastritis / Q000175:diagnosis*; D016481:Helicobacter Infections / Q000175:diagnosis*; D016480:Helicobacter pylori; D006801:Humans; D008297:Male; D008875:Middle Aged; D011237:Predictive Value of Tests; D012307:Risk Factors; D014508:Urea / Q000032:analysis*
D014508:Urea