Special Situations in Argentina: Addressing the Challenges Faced by Individuals on Dialysis Without a Diagnosis.

The third major subgroup requiring admission to dialysis in Argentina are individuals with kidney failure without a known cause, also known as chronic kidney disease of unknown origin (CKDUO). In this retrospective cohort study, the characteristics of this group were described using data from the National Dialysis and Transplant Registry. In Argentina, 113,352 patients commenced maintenance dialysis from April 1, 2004, to December 31, 2021 (213 months); 42% of patients were older than 65 years of age and 2.3% were younger than 18 years of age. There was a predominance of male patients (66,650 [58.8%]) and 6% were foreigners (6,688). Only 9.4% of patients (10,655) had a diagnosis confirmed by a kidney biopsy. The most common causes of kidney disease requiring dialysis admission were diabetic nephropathy (36%), hypertensive nephropathy (21%), and CKDUO (17%). The most frequent dialysis modality was hemodialysis and the majority were admitted with temporary vascular access. Mean survival time from the initiation of dialysis was 44.8 months, with 59.2 months (95% confidence interval, 58.0-60.4) for patients with CKDUO versus 48.6 months (95% confidence interval, 48.2-49.0) for others. Patients with CKDUO were younger and more frequently female, with fewer comorbidities, more precarious socioeconomic status, and indicators of late or absent renal health assistance. There was a heterogeneous renal biopsy rate by state related to the accessibility of diagnostic tools. Health policy and health actions are required to allow kidney health accessibility in earlier stages of chronic kidney disease.