The influence of age on gastro-oesophageal reflux: a re-appraisal of the DeMeester scoring system.

Objective: The statistical evaluation of the influence of age on the pattern of gastro-oesophageal reflux (GOR) identified by prolonged pH monitoring in asymptomatic subjects. Re-appraisal of the DeMeester scoring system for GOR.

Method: Prolonged pH monitoring was performed on 45 asymptomatic elderly adults with normal contrast oesophagogram, manometry and endoscopy. They included 36 males and nine females. The mean age was 66.6 years. The monitoring time ranged between 20 and 24 h, including one complete daily feeding cycle. GOR was defined as a reflux event with a pH of <4. The mean, standard deviation, kurtosis and skew were calculated for six parameters listed in the results. The mean values were compared with those of normal values determined by DeMeester et al. (in: Read NW, editor. Gastrointestinal motility: which test? 1989, pp. 43-52) from their study of 50 young healthy adults, and the t-test was applied to determine the statistical significance of differences. The 'null hypothesis' for each parameter was defined as 'the mean values of the elderly population are not statistically different from DeMeester's normal values'.

Results: The means (+/-SD) of six parameters studied in pH monitoring were as follows: supine reflux time as a percentage of total study time, 2.94+/-5.18%; upright reflux time as a percentage of total study time, 4.14+/-5.71%; total reflux time as a percentage of total study time, 3.5+/-4.38%; duration of longest reflux episode, 14.98+/-24.92 min; number of reflux episodes lasting >5 min, 1.76+/-2.75; total number of reflux episodes during study, 13.49+/-11.31. These results were significantly different from the normal values reported by DeMeester. In addition, the data for each individual parameter was grossly skewed, as well as kurtotic, which implied that the data did not represent a normally distributed population. Moreover, we believe that the equation used for calculation of the DeMeester score, is inappropriate.

Conclusions: The null hypothesis is rejected as the mean values of these parameters in our group are significantly higher than those used as normal. This implies that the normal values defined by DeMeester would over-diagnose gastro-oesophageal reflux disease (GORD). Moreover, we have found that the formula used to calculate the DeMeester's score is not according to the principle it is based on. DeMeester's system scoring is therefore inappropriate.