Effect of kidney stone prevention on urinary risk factors of kidney stone formation and new stone formation: a single center retrospective cohort study.

Abstract

Objective- Nephrolithiasis is an increasingly prevalent and highly recurrent condition. The role of individual preventive measures in preventing recurrence has been established by several randomized controlled trials. However, there is a lack of studies demonstrating the efficacy of combined preventive measures. This single centre retrospective cohort study evaluated the influence of combined
preventive measures on the urinary risk factors for kidney stone formation, symptomatic renal colic rate, kidney stone formation rate and rate of performance of urological procedures.
Patients and methods- Data of nephrolithiasis and nephrocalcinosis patients attending the Kidney stone Prevention clinic (UZ Brussel) between 22/12/2004 and 31/12/2020 were collected in a database. Retrospective cohort analysis was performed by means of a Wilcoxon signed rank test to compare pre- and posttreatment urinary risk factors in patients with at least six months of follow-up.
In patients with at least twelve months follow-up and excluding those with nephrocalcinosis, symptomatic renal colic rate, stone formation rate and urological intervention rate were evaluated by means of the same test.
Results- 835 nephrolithiasis and nephrocalcinosis patients (537 males, 298 females) were evaluated at baseline. In 355 patients, effect of combined preventive measures on urinary risk factors was evaluated. Combined preventive measures significantly reduced median sodium excretion (P<0.05), calciuria (P<0.0001), uricosuria (P<0.0001) and phosphaturia (P<0.005) and significantly increased
median urinary volume (P<0.0001). In patients with hyperoxaluria, increased protein intake, hypocitraturia and low urinary pH at baseline evaluation, combined preventive measures significantly reduced median oxalate excretion (P<0.0001) and protein intake (P<0.0001) and significantly increased median citrate excretion (P<0.0001) and urinary pH (P<0.0001), respectively. Combined preventive measures significantly reduced median symptomatic renal colic rate in 257 patients (P<0.0001), and median urological intervention rate in 254 patients (P<0.0001). The effect of preventive measures on the stone formation rate did not attain statistical significance.
Conclusions- Combined preventive measures have a significant effect on urinary risk factors. Additionally, it leads to a significant decrease in symptomatic renal colic rate and urological intervention rate. These are clinically relevant results for patients and are likely to cause a decrease in nephrolithiasis-related complications and health care costs.

Date of Award	2021
Original language	English
Awarding Institution	Oudstudentenbond - Brussels Alumni
Supervisor	Karl Martin Wissing (Promotor) & Els Van de Perre (Promotor)