Geographical differences of gastric ulcer healing rate in patients treated with ranitidine or placebo

The literature was searched for clinical trials evaluating the use of 300 mg ranitidine daily in the acute treatment of gastric ulcer. All available trials were examined, and the results compared between countries to determine the extent of any geographical variation in ulcer healing rates. Published placebo studies in gastric ulcer were also reviewed for comparison. Sixty-six publications were inspected to determine the trial design, country of origin, gastric ulcer healing rates, determined endoscopically, and details of patient demography. Overall worldwide healing rates for ranitidine treatment were 63% at week 4 and 86% at week 8 (n = 2349 and 2256 respectively), compared with 34% at week 4 and 52% at week 8 for placebo (n = 790 and 231 respectively). Statistically significant differences were found between the healing rates for individual countries at week 4 (P less than 0.001) and week 8 (P less than 0.001). However, after exclusion of the results from Japan (35%, n = 278) and Yugoslavia (97%, n = 32) at week 4, and from Japan (80%, n = 467) and France (65%, n = 52) at week 8, the healing rates from the remaining countries were not statistically different from one another. The limited data available in relation to age, sex and smoking habits, or placebo healing rates contributed little to explaining these aberrant results. It is concluded that there is variation in gastric ulcer healing rates between countries, but only results from Japan seem to be out of line with the rest of the world.