Sample size was estimated based on the hypothesis that HBE would produce a difference of at least 10% in RDQ and SF-36 scores. Effect size (Cohen d) was calculated as 0,49, keeping in mind an RDQ mean and standard deviation of 3,3±1,0 previously found in Spanish population with symptomatic GERD. An SF-36 mean and standard deviation of 56,9±20,3 reported in Italian population in medical therapy with PPI were also taken into account. The minimally important difference selection was chosen based on the assumption that any difference smaller than 10% would have no clinical relevance. Based on this data, 52 patients per group would yield a power greater than 80% for detection of a minimally important difference as large as or larger than 0,6 points in RDQ questionnaire (range: 1 to 6) and 10 points in SF-36 questionnaire (range: 0 to 100). Finally, estimated sample size was incremented by 20% to avoid that eventual losses of follow-up may alter study power. Therefore, final sample size was 124 patients, 62 patients per group.