Managing data for a randomised controlled clinical trial: experience from the WHO Antenatal Care Trial

Abstract

The World Health Organisation, in collaboration with four developing countries, is conducting a randomised controlled clinical trial to evaluate a new programme of antenatal care. In a city or region in Argentina, Cuba, Saudi Arabia and Thailand, 53 clinical units were randomly allocated to provide either the new programme or the programme currently in use. This paper describes the organisation of the data management system used to collect the data. Each woman participating in the trial is uniquely identified, and information such as her name, address and expected delivery date is recorded in the trial ‘subject number list’. If the clinic belongs to the intervention group, information about the woman's eligibility is recorded on the classification form. Details of the outcome of the pregnancy are indicated on two additional case report forms: the antenatal hospital admission form and the summary form. When forms are completed by the investigators, they are submitted to the country data coordinating centre (CDCC). The CDCCs are responsible for the processing of the country study forms. This includes verification of the batch of forms, data capture into computer files, data verification, data validation, production of query sheets for data problems, maintenance and updating of study master files. All operations on data such as additions or modifications are performed using transaction processing. At monthly intervals, recruitment reports and transaction files are sent to the trial coordinating centre in Geneva. All transaction files are processed to accumulate data on the trial's consolidated master files. A monthly report including number of women recruited in the trial, adverse events reported by the countries, recruitment charts by clinic and analyses on eligible women in the intervention group is prepared and submitted to the data safety and monitoring committee. A workshop was organised in 1995, before the start of the trial, to introduce the data management system to the four participating countries. Annual site visits were made to each CDCC to monitor progress. Additional visits were made when major or critical problems could not be solved by the CDCC. At the closure of data collection, a visit is made to review and assess all data management procedures including form filling, maintenance of registers, computer files, query sheets, data modifications. In addition, final cleaning of the data is performed, and an analysis file is produced for inclusion in the centralised trial analyses and in the country‐specific analyses. Based on the experience gained in this trial, the decentralised data management model can be advocated only if CDCCs that will be involved in the trial are already in place with competent and experienced staff. Uniformity of the data management system and of standard operating procedures across countries is also a crucial issue for the effective management of the data collection phase.