Reduction of ureteral stent encrustation by modulating the urine pH and inhibiting the crystal film with a new oral composition: a multicenter, placebo controlled, double blind, randomized clinical trial

Abstract

Background: Encrustation of ureteral double J stents is a common complication that may affect its removal. The aim of the proposed study is to evaluate the efficacy and safety of a new oral composition to prevent double J stent encrustation in indwelling times up to 8 weeks.

Methods: A double-blinded, multicenter, placebo-controlled trial was conducted with 105 patients with indwelling double J stents enrolled across 9 public hospitals in Spain. The patients were randomly assigned (1:1) into intervention (53 patients) or placebo (52 patients) groups for 3 to 8 weeks and both groups self-monitored daily their morning urine pH levels. The primary outcome of analysis was the degree of stent ends encrustation, defined by a 4-point score (0 - none; 3 - global encrustation) using macroscopic and electron microscopy analysis of crystals, after 3 to 8-w indwelling period. Score was exponentially transformed according to calcium levels. Secondary endpoints included urine pH decrease, stent removal, and incidence of adverse events.

Results: The intervention group benefits from a lower global encrustation rate of stent ends than placebo group (1% vs 8.2%; p < 0.018). Mean encrustation score was 85.12 (274.5) in the placebo group and 18.91 (102.27) in the intervention group (p < 0.025). Considering the secondary end points, treated patients reported greater urine pH decreases (p = 0.002). No differences in the incidence of adverse events were identified between the groups.

Conclusions: Our data suggest that the use of this new oral composition is beneficial in the context of ureteral double J indwelling by decreasing mean, as well as global encrustation.

Trial registration: This trial was registered at www.clinicaltrials.gov under the name "Combined Use of a Medical Device and a Dietary Complement in Patient Urinary pH Control in Patients With an Implanted Double J Stent" with date 2nd November 2017, code NCT03343275, and URL.

Keywords: Double J stent; Encrustation; L-methionine; Nutraceutical; Phytin; pH.

Fig. 1

Patient flow chart and allocation

Fig. 2

Encrustation measurement from 0 (nothing) to 4 (global encrustation) measured by radiographic image, microscopic view and electron microscope of the stent

Fig. 3

Multivariate model of Double J ureteral stent encrustation

Fig. 4

Surface of a stent covered by an organic matter layer (conditioning film) in which colonies of bacteria have developed (encrustation classified as 1)

Fig. 5

Surface of a stent covered by dihydrate uric acid deposits, classified as 2. (A) Optical image, (B) Scanning electron microscopy image

Fig. 6

Surface of a stent covered by ammonium magnesium phosphate + hydroxyapatite deposits (A) Optical image, (B) Scanning electron microscopy image. Surface of a stent covered by brushite + hydroxyapatite deposits (C) Optical image, (B) Scanning electron microscopy image