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The acidity index: a simple approach to the measurement of gastric acidity
Author(s) -
Tutuian R.,
Castell D. O.,
Xue S.,
Katz P. O.
Publication year - 2004
Publication title -
alimentary pharmacology and therapeutics
Language(s) - English
Resource type - Journals
SCImago Journal Rank - 3.308
H-Index - 177
eISSN - 1365-2036
pISSN - 0269-2813
DOI - 10.1111/j.1365-2036.2004.01853.x
Subject(s) - chemistry , acidity function , ph meter , chromatography , aqueous solution , organic chemistry
Summary Background : The percentage of time intragastric pH < 4 is a major parameter in evaluating the efficiency of acid‐suppressive therapies. This parameter is easy to calculate, but does not identify the actual pH level. Recent studies have recommended the use of the integrated intragastric acidity as a more refined method of assessing intragastric acid control. Aim : To describe a new parameter, the acidity index, based on the logarithmic aspect of pH calculation, which may overcome the limitations of the percentage of time intragastric pH < 4 and the integrated intragastric acidity. Methods : The acidity index was calculated by obtaining the sum of 1000 × % time pH < 1, 100 × % time pH < 2 and ≥ 1, 10 × % time pH < 3 and ≥ 2 and % time pH < 4 and ≥ 3. The total percentage of time pH < 4 and the integrated intragastric acidity were calculated based on previous descriptions. The correlations between these parameters were analysed. Results : The mean ± s.d. values were 60% ± 22% for the percentage of time pH < 4, 172 ± 178 for the acidity index and 1114 ± 1176 mmol/L.h for the integrated intragastric acidity. Both the integrated intragastric acidity ( r = 0.63) and acidity index ( r = 0.70) showed only fair correlation with the percentage of time pH < 4. In contrast, there was a strong positive correlation ( r = 0.93) between the acidity index and integrated intragastric acidity. Conclusion : The acidity index is easy to calculate, allows a more accurate assessment of the intragastric acidity than does the percentage of time pH < 4, and is comparable with the more complicated integrated gastric acidity in assessing intragastric pH control.