The Dialysis Outcomes and Practice Patterns Study (DOPPS): An international hemodialysis study

The Dialysis Outcomes and Practice Patterns Study (DOPPS) is a prospective, longitudinal, observational study of hemodialysis patients and facilities in seven countries with large populations of dialysis patients: France, Ger many, Italy, Japan, Spain, the United Kingdom, and the United States. This paper describes the study design, analytic methods, and preliminary finding s of the DOPPS. The goal of the study is to determine which practice patter ns are associated with the best patient outcomes, with adjustment for a wid e range of patient case-mix characteristics. The primary outcomes of intere st are mortality, hospitalization, quality of life, and vascular access eve nts. The facility sample from the. seven countries consists of 327 hemodial ysis centers in which 24,392 patients were treated when the study began. A random sample of 10,332 patients has been selected thus far for more detail ed longitudinal data collection. Departing patients are replaced during the study using random selection. A study coordinator at each dialysis facilit y collects baseline and longitudinal patient data. Patients are asked to co mplete a questionnaire that addresses quality of life on a yearly basis. Th e medical director and nurse manager in each facility complete a practice p attern questionnaire. Preliminary data are presented concerning the sample facilities and the census of patients treated in each facility at the start of the study. Dialysis facilities vary widely in size and type (freestandi ng vs, institutionally-based) across countries. Variation is also seen in p atient age, sex distribution, and diabetes mellitus as the attributed cause of endstage renal disease (ESRD). At this early phase, the DOPPS has prove d to be technically feasible and has revealed basic differences in hemodial ysis facilities and patients across the seven participating countries.