Article Text

PDF
PWE-078 Intragastric ph holding time of pH <4 predicts low erosive esophagitis healing rate
  1. Y Yuan,
  2. R H Hunt
  1. Department of Medicine, Farncombe Family Digestive Disease Research Institute, McMaster University, Hamilton, Ontario, Canada

Abstract

Introduction We have previously proposed a linear relationship between the degree and duration of suppression of 24-h intragastric acidity and the healing rate of erosive esophagitis (EE) with the best predictor as per cent time pH ≥4. Poor response to PPI is an increasingly important concern. Simply reporting time pH <4 may not reflect the extent of acid exposure because of the log scale of pH (1 unit pH change is a 10-fold change in [H+ ion] and a 100-fold increase if pH falls from 4 to 2). Indeed, in healthy volunteers ∼40% of the 24-h is pH ≤4 after 5 days esomeprazole 40 mg om and pH is <2 for 42% of the time between midnight and 0700.1 We aimed to investigate the relationship of time pH <4 in the 24-h and the EE healing rate at 4 and 8 weeks with antisecretory drugs, since time pH <4 is the only widely available pH parameter.

Methods A meta-analysis was performed to provide 24-h intragastric pH values at steady state (day 5–8) in healthy volunteers and the EE healing rate at 4 or 8 weeks, by searching the English-language literature up to June 2009 in MEDLINE and EMBASE. For pH data, a weighted mean is only possible by using the sample size of each arm ((mean×n from each study)/Σ treated N). A regimen was excluded if <20 subjects provided pH data. For EE data, the pooled healing rate was calculated by weighting the sample size (random effect model) using StatsDirect®2.6.3. Here also a regimen was excluded if <30 subjects per arm provided EE data. Standard linear regression was performed by SPSS® 17.0, with the pooled EE healing rate at 4 weeks or 8 weeks as the dependent variable and mean per cent time pH <4 in 24-h of the corresponding treatment regimen as the independent variable.

Result 95 studies (411 arms) provided intragastric pH data and 109 studies (243 arms) provided EE healing data for 3 H2-RAs, 5 PPIs and placebo. The commonly reported pH parameter in the pH-EE model was mean per cent time pH <4, which was used in the model. At 4 weeks, the model for the EE (all grades) healing rate = 110.52−1.01* mean per cent time pH <4 in 24 h (R=0.862, p<0.001). At 8 weeks. The model for EE (all grades) healing rate=124.88−1.02* mean per cent time pH <4 in 24 h (R=0.887, p<0.001).

Conclusion Any increase in the time intragastric pH is pH <4 in the 24 h at steady state in healthy volunteers is associated with a decrease in the EE healing rate at 4 and 8 weeks. The per cent time that intragastric pH <4 is a significant predictor for EE non-healing. Although, not usually reported, a better predictor is likely to be the time pH is <3 or better pH <2, especially during the night-time period.

Statistics from Altmetric.com

Request permissions

If you wish to reuse any or all of this article please use the link below which will take you to the Copyright Clearance Center’s RightsLink service. You will be able to get a quick price and instant permission to reuse the content in many different ways.