Associations of Causes of Chronic Kidney Disease with Disease Progression and Mortality: Insights from the Fukuoka Kidney disease Registry (FKR) Study.

Introduction: The Kidney Disease: Improving Global Outcomes guidelines recognize the importance of causes of chronic kidney disease (CKD), glomerular filtration rate, and albuminuria as predictors of kidney outcome and prognosis. However, compared with biopsy-proven causes, there has been limited research regarding the relationship between clinically diagnosed causes of CKD and patient prognosis.

Methods: We examined 3,119 patients with non-dialysis-dependent CKD who participated in the Fukuoka Kidney disease Registry Study, a multicenter prospective cohort study. Patients were divided into six groups: IgA nephropathy, chronic glomerulonephritis (non-biopsy-proven), diabetic nephropathy, hypertensive nephrosclerosis, chronic interstitial nephritis, and polycystic kidney disease. The primary outcomes included a composite kidney outcome, defined as a 1.5-fold increase in serum creatinine and/or the development of end-stage kidney disease, and all-cause mortality. The risks of these outcomes were estimated using a Fine-Gray proportional subdistribution hazards model. Patients with IgA nephropathy, the most prevalent primary glomerulonephritis, served as the reference group.

Results: During the median follow-up period of 5 years, 1,221 patients developed the composite kidney outcome, and 346 patients died. Compared with IgA nephropathy, the multivariable-adjusted subdistribution hazard ratios (sHRs) for the composite kidney outcome were significantly higher in diabetic nephropathy (sHR 1.45) and polycystic kidney disease (sHR 2.07) groups, whereas the chronic interstitial nephritis group had a significantly lower risk (sHR 0.71). The risk of all-cause mortality was significantly higher in the hypertensive nephrosclerosis group (sHR 1.90).

Conclusion: The causes of CKD were associated with risks of the composite kidney outcome and all-cause mortality, highlighting their clinical relevance in predicting prognosis. These findings suggest that different causes of CKD have distinct impacts on patient outcomes, emphasizing the importance of tailoring management strategies according to the underlying causes.