The EDTA-ERA Registry—its history and further evolution

development has been spectacular during the last 30 years. The first Registry Report was published in the EDTA Proceedings in 1965 and included data received from 43 European centres. William Drukker, who was one of the founders of the EDTA, was responsible for the idea of establishing this Registry, the growth of which was extremely rapid. In 1970, 217 centres reported data regarding their patients and, at that point, 6164 patients from 29 different countries were registered in the files. In 1980, the number of patients had risen to 91 866 and 1185 centres were reporting to the Registry. Finally, in 1994, the total number of registered patients was 466 711 from 2942 centres in 34 countries. Each year, the scientific activities of the EDTA-ERA Congress begin with the Annual Registry Report, which for the last 30 years, has supplied demographic information and data regarding the different modalities of renal replacement therapy, results and principal complications. Comparative data from different geographical areas and countries has been analysed. The Registry has reported on the incidence of end-stage renal disease, as well as the variations in the profiles of new patients over time. The increase in mean age of patients, the changes in primary renal diseases causing end-stage renal disease, the prevalence of the different forms of haemodialysis and peritoneal dialysis in use, the growth of the number of transplants in the different European countries, the incidence of pregnancies, parathyroidectomies and malignant disease are some examples of scientific data supplied by the Registry. The Annual Registry Report is repeatedly cited as a reference in the majority of publications regarding end-stage renal disease. The Registry is based on a patient questionnaire which initially collected the patients' personal data, primary renal disease, the different types of treatment over time, the cause and date of death and some additional questions regarding dialysis treatment, other associated treatments such as erythropoietin or parathyroidectomy and data related to transplants, such as the type of donor and immunosuppressive drugs administered. 1937 Over the years, questions were modified and added to the patient questionnaire and a centre questionnaire was created with the objective of obtaining general demographic data about incidence and prevalence, as well as questions regarding policies and practices in reference to renal replacement therapies. As the Registry grew, increasing the number of patients and dialysis centres reporting, various problems arose. The EDTA is a scientific society and not an official institution, and the Registry is voluntary. For this reason, the percentage of centres failing to send their data to the Registry has increased over the years. In addition, the scientific temptation to study patients' problems more in depth gradually complicated the questionnaires, adding a new difficulty for the centres reporting a large number of patients. Two years ago, changes were introduced in the EDTA-ERA Registry as a consequence of these problems. To increase the response rate, these changes were directed at facilitating the work required of the centres. Rigid quality control of data has also been introduced. To achieve these objectives, the number of questions on the patient questionnaire was reduced to those relating to age, sex, primary renal disease, type of treatment, comorbidity, and death. The most important advance has been to create a computer software system for data collection, supplied free-of-charge to the centres. The new software, called McPas, allows the centres to introduce the new patients data day by day and update existing patients. The centre can also use this software to analyse its own data, produce its own reports and deliver them to the Registry on floppy disk. Reducing the number of questions could result in a loss of information. To avoid this and, above all, to be able to study certain topics in a strictly scientific manner, the Registry is developing several studies on samples, which in the majority of cases will be prospective. The definition of the patient samples under strict statistical and epidemiological control will allow studies of high scientific quality to be carried out on a relatively small number of patients. Quality assurance in renal replacement therapy (RRT)