Despite effective therapeutic strategies to slow or arrest the progression of chronic renal diseases, the number of patients entering renal replacement programs is increasing, with a dramatic burden in terms of morbidity, mortality and resource consumption. While in the past the attention was mainly devoted to the improvement of dialysis care, it has recently been argued that the timing and quality of care before dialysis is started may significantly affect the prognosis. Problems of transfer of research results, together with differences in physicians' attitudes and beliefs as well as in structural and organisational aspects make pre-end-stage renal disease (ESRD) care extremely heterogeneous. This lack of uniformity in medical practice has stimulated extensive inquiry into the relation between the use of clinical services and their end results--the outcomes. Outcomes research investigates medical effectiveness, meaning how well prevailing treatments work in different clinical practice settings. It is thus an important tool to help patients, providers and purchasers to make sound decisions, based on a deeper knowledge of how different choices affect the patient's life. By using a broad array of outcome measures, this research serves to evaluate the effectiveness of complex health care strategies from the different points of view of patients, providers and purchasers, reconciling their needs. Starting from these premises, initiatives aimed to evaluate the avoidability of ESRD morbidity and mortality are urgently needed. To this purpose, the care delivered to ESRD patients and its impact on clinical variables, quality of life and resource consumption need to be longitudinally monitored. Outcomes research thus represents a unique opportunity to increase our knowledge on pre-ESRD care and to identify those strategies more likely to reduce the unwanted outcomes related to the initiation of dialytic treatment.