Heartburn severity can predict pathologic oesophageal reflux in gastro-oesophageal reflux disease patients treated with a proton-pump inhibitor

The effects of changing temperature correction factors on measures of acidity calculated from gastric and oesophageal pH recordings

BACKGROUND

Recently, Medtronic notified customers that new correction factors should be used for their Slimline and Zinetics24 single-use, internal-standard pH catheters.

AIM AND METHODS

We selected 24-h recordings of oesophageal and gastric pH with the Zinetics24 from our archives for five healthy subjects and for five gastro-oesophageal reflux disease subjects who were studied at baseline and again after 8 days of treatment with a proton-pump inhibitor. All pH values obtained with the old correction factors were rescaled using the new correction factors. Values for median pH, integrated acidity and time pH < or = 4 were then calculated from pH values with old and new correction factors.

RESULTS

The new correction factors changed values for median pH, integrated acidity and time pH < or = 4. Values for median pH and integrated acidity changed in a predictable, proportionate way, whereas values for time pH < or = 4 did not.

CONCLUSIONS

The new correction factors will not change the interpretation of previously published results with median pH or integrated acidity. In contrast, values for time < or =4 cannot be converted in an obvious way with the new correction factors. Instead, the raw pH data will need to be rescaled and values for time pH < or = 4 recalculated using the rescaled pH data.

Postprandial oesophageal integrated acidity is a reliable predictor of gastro-oesophageal reflux disease

BACKGROUND

Measurement of oesophageal acid exposure parameters postprandially has been shown to distinguish gastro-oesophageal reflux disease patients from normal individuals.

AIMS

To calculate the accuracy of postprandial oesophageal integrated acidity in diagnosing gastro-oesophageal reflux disease.

METHODS

Ambulatory 24-h pH studies of 626 patients were analysed retrospectively. Gastro-oesophageal reflux disease, defined as pH < 4 for > 4.2% of time, was identified in 305 subjects. Postprandial oesophageal integrated acidity was measured for 2 and 3 h after the largest meal peak as determined from gastric pH. Postprandial symptom-associated probability was calculated.

RESULTS

Gastro-oesophageal reflux disease subjects had a greater postprandial oesophageal integrated acidity than non-gastro-oesophageal reflux disease subjects [median (IQR): 0.57 (0.08-2.66) vs. 0.03 (0.01-0.15) mmol*h/L]. Median postprandial oesophageal integrated acidity did not differ with gender or age in gastro-oesophageal reflux disease and non-gastro-oesophageal reflux disease subjects (P > 0.05 for all). A 3-h postprandial oesophageal integrated acidity value of 0.121 mmol*h/L had a 71.1% sensitivity and 71.7% specificity in diagnosing gastro-oesophageal reflux disease. Gastro-oesophageal reflux disease subjects with symptoms had a higher postprandial oesophageal integrated acidity than those without (P = 0.043), whereas non-gastro-oesophageal reflux disease subjects with and without symptoms did not differ (P = 0.74). The correlation between symptom-associated probability and postprandial oesophageal integrated acidity was poor (gastro-oesophageal reflux disease: r = 0.15; non-gastro-oesophageal reflux disease: r = 0.25).

CONCLUSION

Postprandial oesophageal integrated acidity provides a robust estimation of oesophageal acid exposure and may predict symptoms in gastro-oesophageal reflux disease patients.

Irritable bowel, smoking and oesophageal acid exposure: an insight into the nature of symptoms of gastro-oesophageal reflux

BACKGROUND

In gastro-oesophageal reflux disease, oesophageal acid exposure correlates with symptoms but explains only a small fraction of their variance.

AIMS

To elucidate the effects of irritable bowel syndrome and smoking on gastro-oesophageal reflux disease symptoms and to clarify whether they modulate the relationship between oesophageal acid exposure and symptoms.

METHODS

The relationship between oesophageal acid exposure, irritable bowel syndrome (Rome I criteria), smoking status and symptoms was investigated in patients with a normal gastroscopy who underwent a 24-h oesophageal pH monitoring.

RESULTS

Of 256 patients with gastro-oesophageal reflux disease, 16% were smokers and 50% met the criteria for irritable bowel syndrome (irritable bowel syndrome+). The extent of oesophageal acid exposure was unrelated to smoking or irritable bowel syndrome status. Oesophageal acid exposure, irritable bowel syndrome status and current smoking independently predicted symptoms. Irritable bowel syndrome and smoking modulated the effect of oesophageal acid exposure on symptoms: oesophageal acid exposure was predictive of symptoms only in non-smokers. However, irritable bowel syndrome was a significant predictor of symptoms both in smokers and in non-smokers. Smoking was associated with symptoms only in irritable bowel syndrome+, while oesophageal acid exposure was associated with symptoms irrespective of irritable bowel syndrome status.

CONCLUSIONS

In patients with non-erosive gastro-oesophageal reflux disease, smoking and irritable bowel syndrome independently predicted symptoms, without affecting the extent of oesophageal acid exposure. The relationship between oesophageal acid exposure and symptoms was affected significantly, and in opposite directions, by smoking and irritable bowel syndrome.

The basis for the decreased response to proton pump inhibitors in gastro-oesophageal reflux disease patients without erosive oesophagitis

BACKGROUND

The reason why heartburn in gastro-oesophageal reflux disease subjects without oesophagitis is less responsive to proton pump inhibitors than heartburn in those with erosive oesophagitis is not known.

METHODS

Gastric and oesophageal pH were determined in 26 subjects with gastro-oesophageal reflux disease at baseline and on days 1, 2 and 8 of treatment with 20 mg omeprazole or 20 mg rabeprazole in a randomized, two-way cross-over fashion. The presence or absence of erosive oesophagitis at baseline was documented by upper gastrointestinal endoscopy.

RESULTS

At a given value of the integrated gastric acidity during treatment with a proton pump inhibitor, the probability of pathological oesophageal reflux was significantly higher in subjects with no oesophagitis than in those with erosive oesophagitis. This occurred because the post-prandial gastric acidity in subjects with no oesophagitis showed a decreased response to the antisecretory agent.

CONCLUSIONS

Compared with gastro-oesophageal reflux disease subjects with erosive oesophagitis, those with no oesophagitis are relatively refractory to the pharmacodynamic effects of proton pump inhibitors on the post-prandial integrated gastric acidity.