Compliance with anti-ulcer medication during short-term healing phase clinical trials.

Nine hundred and sixty-six patients' compliance with drug therapy of peptic ulcerations and reflux oesophagitis in four clinical trials were studied. The mean compliance rates varied from 90.5% (95% C.I. 89.0-92.1%) to 99.2% (95% C.I. 98.2-100.1%). Compliance declined significantly with increasing complexity of the dosage schedule in all trials, and toward the end of the treatment period in two of them. Patients with adverse events had a significant drop in compliance during the last part of the treatment period in one of the trials. There was a significant inter-centre variation in compliance. Overall, the variation was of little clinical significance. Patient compliance was independent of age, sex, use of alcohol and tobacco, effect of treatment, concomitant drug therapy and whether the pill was active drug or placebo. The study shows that a simplified dosage schedule, shortening of the treatment period, use of drugs with minimal side-effects, and meticulous selection of centres could improve patient compliance with drug therapy in clinical trials.