Clinicopathological cohort study of kidney biopsy findings resulting in dialysis during long-term follow-up exceeding 30 years.

BACKGROUND

Numerous kidney diseases progress to end-stage kidney disease (ESKD); however, a limited number of cohort studies have evaluated the underlying kidney diseases through kidney biopsy (KB).

METHODS

We retrospectively evaluated all patients who initiated dialysis at Toranomon Hospital, Japan, from 1985 to 2019, and whose underlying kidney disease had been diagnosed by KB. The data on histopathological diagnosis and various clinical characteristics were collected and analyzed for 357 patients.

RESULTS

The most prevalent underlying diseases, which constituted the primary endpoint of this study, were diabetic nephropathy (DN; n = 100, 28.0%), IgA nephropathy (IgAN; n = 99, 27.7%), and focal segmental glomerulosclerosis (n = 34, 9.5%). Benign nephrosclerosis (BNS; n = 1, 0.3%), that is, arteriosclerosis/arteriolosclerosis without distinct glomerulopathy, was rare. As the secondary endpoint, Cox regression analysis revealed that lower eGFR (p < 0.0001), higher proteinuria (p < 0.0001), older age (p = 0.005) and presence of DN (p = 0.008) were significant independent risk factors for early dialysis initiation. In the subgroup analysis, when comparing DN and IgAN, significantly earlier dialysis initiation was observed in DN than in IgAN by log-rank analysis (p < 0.0001), as well as after adjustment for baseline clinical characteristics using propensity score matching (n = 45 each) (p = 0.023).

CONCLUSIONS

We identified a list of kidney diseases that were at risk for ESKD at the time of KB through a long-term follow-up. DN and IgAN are the two primary causes of ESKD, whereas BNS is an infrequent direct cause of ESKD in patients requiring kidney biopsy.