COMPARISON OF SEQUENTIAL AND FIXED-SAMPLE DESIGNS IN A CONTROLLED CLINICAL-TRIAL WITH LAPAROSCOPIC VERSUS CONVENTIONAL CHOLECYSTECTOMY

Background: The aim of this study was to compare a fixed-sample and a sequential design with regard to study duration, sample size, and medi cal results in a real-life situation. Methods: A randomized study comp aring laparoscopic and conventional cholecystectomy was carried out wi th a fixed-sample design, parallel with a sequential design. The main variable was duration of postoperative convalescence. Results: In the fixed-sample trial the necessary number of patients was calculated to be 72. The sequential trial was conclusive after inclusion of 24 patie nts and reduced the duration of the study from 43 to 18 weeks. Additio nally, the sequential trial reached the same conclusions as the fixed- sample trial in all the observed variables except for one. Conclusion: The present study indicates that sequential design should be used mor e frequently in clinical trials, to involve the smallest possible numb er of patients necessary to reach a conclusion.