Analysis of 33,616 urinary stone cases: novel findings on renal transplantation impact, comorbidity profiles, and composition patterns.
Level 3 - non-randomized controlled study
Retrospective propensity score-matched comparative cohort study
PubMed 41939899 · doi:10.3389/fimmu.2026.1757548
What was done
This retrospective observational study analyzed 33,616 urinary stone samples collected between April 2014 and December 2024 from two hospitals in Southern China. Stone composition was evaluated using Fourier Transform-Infrared Spectrometry, comparing 69 renal transplant recipients with nephrolithiasis against 33,547 non-transplant stone formers. Propensity score matching (1:2) was performed, yielding 69 transplant cases and 139 matched controls, followed by logistic regression with progressive adjustment and subgroup analyses.
What was found
Before matching, transplant recipients showed higher rates of carbonate apatite stones (37.7% vs. 16.4%, p < 0.001) and lower rates of calcium oxalate monohydrate stones (39.1% vs. 63.7%) compared to non-transplant controls. After propensity score matching with 139 controls, these differences persisted (carbonate apatite: 37.7% vs. 15.8%; calcium oxalate monohydrate: 39.1% vs. 66.9%, p = 0.001). Transplantation was associated with lower odds of calcium oxalate stones (OR 0.32, 95% CI: 0.17–0.57, p < 0.001) and higher odds of carbonate apatite stones (unadjusted OR 3.22, 95% CI: 1.66–6.32, p < 0.001; adjusted OR 2.82, 95% CI: 1.37–5.82). Carbonate apatite stones were also associated with renal atrophy (OR 4.37, 95% CI: 1.49–13.17, p = 0.007) and urinary tract strictures (OR 2.50, 95% CI: 1.06–5.75, p = 0.032). Transplant recipients had a higher proportion of mixed stones (58.0% vs. 39.6%, p = 0.018).
Why it matters
The study demonstrates a distinct compositional shift in kidney transplant recipients toward carbonate apatite and mixed stones instead of typical calcium oxalate stones. This underscores the need for post-transplant-specific prevention and management protocols.
Limits
The transplant stone-forming group was small (n = 69) relative to the total cohort. The retrospective design from two regional centers in China limits generalizability. The abstract does not report metabolic workups (such as 24-hour urine chemistries), specific immunosuppressive regimens, stone recurrence rates, or longitudinal graft survival outcomes.
Cited by
- supports Calcium oxalate stones represent the most common type of kidney stones.