Stesura Seveso Archivio Italiano di Urologia e Andrologia 2025; 97(3):13991 1 ORIGINAL PAPER ial (1). The formation of biofilms and colonization by ure- ase-producing bacteria (such as Proteus, Pseudomonas, and Klebsiella) may contribute to the development of encrusta- tions (2, 3). However, encrustations have also been observed in sterile conditions, and the most common com- position identified on DJ stents is not struvite but calcium oxalate, indicating that other factors could be involved (4, 5). Urine conditions, including pH, supersaturation of crys- tallizing substances, and a deficiency of crystallizing inhibitors, play a significant role, as DJ stents remain in con- stant contact with urine (4, 6). Numerous other factors have been linked to the formation of encrustations, with indwelling time being the most extensively studied (2, 7). Encrustation of ureteric stents could lead to severe com- plications, that occurs in up to 13% of cases of prolonged indwelling time or forgotten stent (8). Marked encrusta- tions could compromise its tensile strength, potentially leading to stent fragmentation during removal. Furthermore, such encrustations may cause damage or avulsion of the ureter during the removal procedure, uri- nary tract infections, or even result in the loss of the renal unit if they cause chronic obstruction of stent drainage (2, 9, 10). Various procedures may be necessary to retrieve neglect- ed DJ stents, including Shock Wave Lithotripsy (SWL), ureteroscopy, and percutaneous techniques. Open sur- gery, on the other hand, is seldom required (11, 12). Torrecilla et al. investigated the efficacy of a new oral med- ication in preventing DJ stent encrustations. The oral composition studied contained both urine acidifier and crystallization inhibitors, and they reported a significant decrease in stent encrustations (13). Studies have indicated that oral Ascorbic Acid intake can lead to urine acidification (14, 15). We conducted the current study to investigate the impact of daily Ascorbic Acid supplementation on reducing the incidence of encrustations on DJ ureteric stents. We high- lighted the incidence of stent encrustations, predictive factors, and associated morbidities. Background: Double J (DJ) Ureteric stent encrustation is a troublesome complication that may impede its removal. The proposed study aims to inves- tigate the effect of ascorbic acid supplementation on reducing DJ stent encrustations and identify potential risk factors. Methods: A multi-center, non-concurrent cohort study involved patients who had DJ ureteric stents from July 2017 to January 2024. Group I comprised 359 patients who took 500 mg of ascorbic acid supplements three times daily that continued until the time of DJ removal. In contrast, Group II consisted of 483 patients who did not use the supplement. The study groups were compared in terms of patient demographics, stone criteria, double-J stent encrustations, and stent-related adverse events. KUB grading system for stent encrustations was utilized. Results: The study enrolled 842 patients with a prevalence of stent encrustations of 20.43%. The mean K, U, and B scores were 2.14, 1.91, and 2.15, respectively, and the mean total K.U.B. score was 6.2 ± 2.91. The study groups were comparable in terms of patient demographics; however, nine patients (2.5%) in group I had stent encrustations, compared to 163 (33.7%) in group II, with a statistically significant difference (p < 0.001). Urinary tract infections (UTIs) were more prevalent in group II at 57.8%, compared to 30% in group I (p = 0.02). Lack of treat- ment with ascorbic acid male gender, and longer duration of indwelling stents were significant predictors of stent encrusta- tions (p < 0.05). Conclusions: Our study has demonstrated that ascorbic acid sup- plementation could reduce the incidence of encrustations on dou- ble-J ureteric stents. Lack of ascorbic acid administration, male gender, and prolonged stent indwelling time were significant predictors for stent encrustations. KEY WORDS: Double-J; Encrustation; Indwelling time; Urine acidification. Submitted 16 May 2025; Accepted 26 July 2025 INTRODUCTION Double-J (DJ) ureteric stent encrustations is an area that requires further investigations, as it is primarily multifactor- Ascorbic acid supplementation effectiveness in reducing Double-J ureteric stent encrustations. A multicenter perspective Adel Elatreisy 1, 2, Ahmed Alrefaey 1, Osama Shalkamy 1, Mohamed A Elhelaly 1, El-Sayed El-Agamy 1, Abdrabuh M Adrabuh 1, Hany Eldamanhory 1, Ahmed Mohamed Soliman 1, Hossam A Shouman 1, Mohamed Shehab 1, Nader A Abdelkhalek 1, Ahmed Shafiea 1, Tamer Ewida 3, Mohamed Elsalhy 1, Maged Kamal Fayad 4, Hamada Ahmed Youssof 5 1 Department of Urology, Faculty of Medicine, Al-Azhar University, Cairo, Egypt; 2 Department of Urology, King Fahd Armed Forces Hospital, Jeddah, KSA; 3 Urology department, Blackpool teaching hospital, Blackpool, UK; 4 National Institute of Urology and Nephrology, Cairo, Egypt; 5 Department of Urology, Faculty of Medicine, Fayoum University, Fayoum, Egypt. DOI: 10.4081/aiua.2025.13991 Summary Archivio Italiano di Urologia e Andrologia 2025; 97(3):13991 A. Elatreisy, A. Alrefaey, O. Shalkamy, et al. 2 MATERIALS AND METHODS A multi-center non-concurrent cohort study involved patients with DJ ureteric stents treated at three tertiary care hospitals. The study was conducted between July 2017 and January 2024, and the local institutional review board for the Urology Department, Faculty of Medicine, Al- Azhar University, approved the protocol (Study Protocol ID Number: UroAzhar-021-12). The study included adult patients aged 18 years or older who underwent endourology procedures for stone man- agement with the insertion of DJ ureteric stents. We pre- scribed a three-times-daily oral Ascorbic Acid dose of 500 mg (total 1500 mg per day) aiming to reduce DJ stent encrustation. The treatment was prescribed as a home medication on discharge after DJ stent insertion and con- tinued until the time of DJ removal. We excluded patients with silicone ureteric stents and those with incomplete files from our study. Before DJ removal, every patient had a kidney-ureter-blad- der (KUB) x-ray, while patients with neglected stents required a non-contrasted computed tomography (NCCT). Contrast imaging studies were occasionally necessary to obtain detailed calyceal anatomy. Laboratory investiga- tions, including serum creatinine, complete blood count, coagulation profile, and urinary culture, were obtained. If the urinary culture results were positive, the patients were treated accordingly, and DJ stent removal was sub- sequently performed. We used the scoring system proposed by Arenas et al. to assess the level and severity of DJ stent encrustations. The KUB system grades each portion of the stent individually on a scale of 1 to 5 based on the severity of the encrustation. This includes the proximal renal coil (graded as "K"), the ureteral shaft (graded as "U"), and the distal bladder coil (graded as "B"). The cumulative KUB score is obtained by adding the scores of all three portions of the stent, with a maximum score of 15 (16). Patients received prophylactic antibiotics before undergoing DJ stent removal with spinal, gener- al, or urethral topical anesthesia. Double-J ureteric stents were removed using a cystoscope and forceps, sometimes with the help of SWL or ureteroscopy and laser fragmentation. In extreme cases, cystolithotripsy and percuta- neous nephrolithotomy were necessary for stent removal. If the procedure was prolonged, the stent was replaced with a new one. The cohort was divided into two distinct groups. Group I comprised 359 patients who demonstrated regular compliance with the daily oral ascorbic acid regimen. In contrast, Group II consisted of 483 patients who did not use the supplement. The study groups were compared in terms of patient demographics, stone criteria, DJ stent encrustations, and stent-related adverse events. Perioperative complications were graded according to the modified Clavien-Dindo classi- fication system (17). Neglected stents were defined as a duration of indwelling exceeding 6 months. A logistic regression model was used to analyze the risk factors that may lead to DJ tent encrustations. The ana- lyzed variables included patient demographics, laborato- ry profile (such as urine culture, serum creatinine, and blood sugar), indwelling time, and regular use of Ascorbic Acid supplement throughout stent indwelling. Statistical analysis The data was analyzed using Statistical Package for Social Science (SPSS) version 29 software. Numerical data were summarized using means and stan- dard deviations, while categorical data were summarized as numbers (percentages). We used an independent t-test for normally distributed numeric variables, the Mann-Whitney test for non-nor- mally distributed variables, and Chi-square and Fisher's exact tests for categorical variables. A logistic regression analysis was done to identify predic- tors of stent encrustation. Univariate analysis was con- ducted for all variables expected to affect stent encrusta- tions. The significant variables were included in the logis- tic multivariate regression stepwise model, presented by odds ratio (OR) and its confidence interval (CI). Results were considered significant when p < 0.05. RESULTS The study involved 842 patients, with a mean age of 41.58 ± 17.42. Out of these, 172 patients (20.43%) developed stent encrustations. The mean K, U, and B scores were 2.14, 1.91, and 2.15, respectively, and the mean total Table 1. Patients' demographic data and outcomes in the study groups. Variables Group I Group II P value (n = 359) (n = 483) Age, years, Mean (SD) 42.12 (16.06) 40.64 (18.10) 0.762 Gender, N (%) Male 219 (61%) 313 (64.8%) 0.24 Female 140 (39%) 170 (35.2%) History of urinary stone, N (%) No 38 (10.6%) 44 (9.1%) 0.5 Yes 321 (89.4%) 439 (90.9%) Kidney 181 (56.4%) 239 (54.4.2%) Ureter 92 (28.7%) 140 (31.9%) Kidney/ureter 48 (14.9%) 60 (13.7%) Indwelling time (days), Mean (SD) 199 (176) 328 (298) < 0.001 Neglected Stents, N (%) 49 (13.6%) 120 (24.8%) 0.06 BMI, Mean (SD) 25.72 (2.84) 26.24 (2.62) 0.1 Preoperative serum creatinine, mg/dL Mean (SD) 1.16 (0.42) 1.14 (0.57) 0.16 Occurrence of double-J stent encrustations, N (%) Yes 9 (2.5%) 163 (33.7%) < 0.001 No 350 (97.5%) 320 (66.63%) Perioperative complications according to modified Clavien-Dindo classification system, N (%) Storage LUTS (Grade I) 91 (25.3%) 191(39.5%) 0.02 UTI (Grade II) 108 (30%) 279 (57.8%) 0.06 Hematuria (Grade I) 129 (35.9%) 146 (30.2%) 0.76 BMI: Body mass index; SD: Standard deviation, LUTS: Lower urinary tract symptoms, UTI: Urinary tract infection. Archivio Italiano di Urologia e Andrologia 2025; 97(3):13991 3 Ascorbic acid and prevention of stent encrustations K.U.B. score was 6.2 ± 2.91. The patient demographics and stone characteristics of the study groups were similar, as shown in Table 1. It was found that 2.5% of patients in group I presented with DJ stent encrusta- tions, compared to 33.7% of patients in group II, with a statistically significant differ- ence (p < 0.001). Double-J stent encrustations were more fre- quent in males (78.49%). 135 out of 532 male patients (25.38%) developed DJ stent encrustations compared to 11.82% of female patients with a statistically signifi- cant difference (p = 0.004) (Table 2). DJ stent encrustation was more frequent in patients with prolonged stenting time or neglected stents; the median duration of stenting time in cases with encrustations was 278 days compared to 119 days in those with no encrustations (p < 0.001) as depicted in Table 2. Regarding DJ-associated adverse events, urinary tract infection (UTI) was more preva- lent in group II at 57.8%, compared to 30% in group I (p = 0.02). Similarly, storage lower urinary tract symptoms (LUTS) were reported in 25.3% and 39.5% of groups I and II, respectively (p = 0.06). Hematuria was reported in 35.9% and 30.2% of cases in group I and II, respectively, with no sta- tistically significant difference, as illustrated in Table 1. Univariate analysis revealed that several variables may contribute to DJ ureteric stent encrustations. However, the multi- variate logistic regression model demon- strated that lack of ascorbic acid intake, male gender, and longer duration of indwelling stent were significant predictors of stent encrustations (p < 0.05), as depict- ed in Table 3. DISCUSSION The encrustation of DJ stents can lead to significant clin- ical consequences that may impede the removal of the stents. The duration of stent placement is directly pro- portional to the probability of encrustation (1) (17-19). In some cases, this can result in complete encrustation, necessitating endourological procedures, SWL, or open surgery for stent removal (20, 21). According to some reports, the mere presence of a biofilm on a stent can intensify a patient's discomfort and lead to LUTS (3, 22). In this study, about 20% of patients with DJ ureteric stents had encrustations. Other studies have reported a prevalence rate from 9% to 76% (1, 11, 25, 26). The rea- son for this variation is unclear, but it may be due to dif- ferences in the population and the duration of indwelling time in each study. Nevertheless, most studies have shown a high prevalence of encrustations. Torrecilla et al. conducted a study on the effect of urinary pH on the development rate of crystals and subsequent encrustations around the DJ stent. Their findings suggest that when urinary pH values are within the range of 5.5 to 6.2, the crystals development rate and encrustation formation are significantly reduced (13). Conversely, other researchers have reported that when urinary pH is less than 6.2, the risk of stent encrustation increases by 13-fold (23, 24). The development of significant calcium phosphate deposits depends upon specific conditions in urine with a pH exceeding 6.2 and no bacterial colonization. Brushite deposits can accumulate in large quantities when urine has a high calcium concentration, a citrate deficit, and a pH level greater than 6.2. Such conditions can also lead to the occurrence of large calcium oxalate dihydrate crystals. Large hydroxyapatite deposits, on the other hand, can develop when calcium and magnesium con- centrations are low (13). According to certain reports, the intake of ascorbic acid has been observed to cause urine acidification without affecting serum pH levels. This acidification has been Table 2. Demographic data of patients with and without stent encrustations. Variables Encrustation No Encrustation P value (n = 172) (n =670) Age, years, Mean (SD) 41.92 (16.06) 40.84 (18.10) 0.65 Gender, N (%) Male 135 (78.49%) 397 (59.25%) 0.004 Female 37 (21.51%) 273 (40.75%) History of urinary stone, N (%) No 10 (5.81%) 72 (10.75%) 0.001 Yes 162 (94.19%) 598 (89.25%) Indwelling time (days), Mean (SD) 378 (321) 149 (28) < 0.001 Neglected Stents, N (%) 132 (78.1%) 37 (21.9%) < 0.001 Ascorbic acid intake, N (%) Yes 9 (5.2%) 350 (52.2%) < 0.001 No 163 (94.8%) 320 ( 47.8%) BMI, Mean (SD) 26.12 (2.14) 25.74 (2.92) 0.2 Preoperative serum creatinine, mg/dL Mean (SD) 1.24 (0.4) 1.06( 0.48) 0.18 BMI: Body mass index; SD: Standard deviation. Table 3. Univariate and multivariate logistic regression models for the variables associated with stent encrustations. Univariate analysis Multivariate analysis HR (95% CI) P value HR (95% CI) P value Age 1.42 (0.69, 2.92) 0.334 --- --- Gender 0.56 (0.33, 0.95) 0.032 1.80 (1.11, 2.94) 0.018 Duration of indwelling stents/days 1.01 (1.00, 1.01) < 0.001 1.01 (1.01, 1.01) < 0.001 History of stone --- 0.9 --- --- BMI 0.99 (0.90, 1.08) 0.802 --- --- Urine acidification 0.03 (0.01, 0.08) < 0.001 30.99 (12.70, 75.56) < 0.001 UTI 1.71 (0.99, 2.96) 0.054 --- --- Mean (SD) 1.24 (0.4) 1.06 (0.48) 0.18 BMI: Body mass index; UTI: Urinary tract infection. Archivio Italiano di Urologia e Andrologia 2025; 97(3):13991 A. Elatreisy, A. Alrefaey, O. Shalkamy, et al. 4 associated with mild calciuria; however, this is balanced by an increase in the solubility of calcium phosphate in acidic urine. (14, 15). Consequently, the decrease in the incidence of DJ stent encrustation resulting from daily ascorbic acid intake could be attributed to its role as a urine acidifier. This observation could be explained by the reduced rate of uri- nary tract infection and bacterial colonization in an acidi- fied environment. These findings are consistent with ear- lier studies demonstrating a connection between a lack of acidification, urinary tract infection, bacterial biofilm for- mation, and consequent stent encrustations (13, 25, 26). Some reports have shown significant hyperoxaluria in patients with calcium stone formation after high doses of oral ascorbic acid intake (2-10 g per day) (14). However, in our study, we used a daily dose of 1.5 gm. The present study has demonstrated a considerable effi- cacy of daily oral administration of Ascorbic Acid, which could act as a urine acidifier, in mitigating the incidence of DJ ureteric stent encrustations. Our findings could be consistent with those reported by Torrecilla et al., who demonstrated promising outcomes by using a novel com- pound comprising a urine acidifier and a crystallization inhibitor to decrease ureteric stent encrustation (13). Our study found that male patients have a higher inci- dence of double-J ureteric stent encrustations, with a prevalence of 25.52%, compared to 11.82% in females. This trend can be attributed to hormonal differences and higher citrate levels in females (27, 28). Several risk factors have been studied regarding the forma- tion of encrustations on DJ stents, including recurrent uri- nary tract infections and stone recurrence. A higher preva- lence of stent encrustations has been observed in individu- als with a history of recurrent stones, as evidenced by numerous studies (1) although our study did not identify stone recurrence as a risk factor for stent encrustation. As noted previously, the present study has demonstrated that patients with neglected ureteric stents are at an increased risk of developing stent-related complications, including recurrent urinary tract infections, stent frag- mentation, and stent migration (20, 29, 30). Numerous studies have explored the potential of Ascorbic Acid supplementation to reduce urine pH in patients suffering from recurrent urinary tract infections or stone formers with alkaline urine. However, no studies have assessed the impact of ascorbic acid supplementa- tion on the incidence of ureteric double-J stent encrusta- tions. Our research represents the first investigation of this nature and demonstrates that Ascorbic Acid supple- mentation can significantly reduce the incidence of ureteric DJ stent encrustations. The study limitations Despite the substantial sample size, this cohort study has limitations that warrant careful consideration. 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Emerging Mobile DECLARATIONS Ethical approval and consent for participate: The study fol- lowed ethical standards outlined in the Declaration of Helsinki and was approved by the Institutional Review Board of the Authors’Institute (protocol (Study Protocol ID Number: UroAzhar-021-12). Due to feasibility and unchanged review results, informed consent was waived for 842 individuals whose medical records were reviewed. Consent for publication: Not Applicable. Availability of data and material: The datasets used during this study are available from the corresponding author on rea- sonable request. Competing interests: The authors state that they do not have any conflicting interest. Funding: None. Authors' contributions: All authors have made significant con- tributions to the study's conception and design, methodology, data acquisition, analysis, review, and interpretation. 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Correspondence Adel Elatreisy, MD, MSc, PhD (Urol), FEBU, FRCS (Urol) (Corresponding author) dr_adelelatreisy@yahoo.com; adel.elatreisy@azhar.edu.eg Urology Department, Faculty of Medicine, Al-Azhar university, Cairo, Egypt and Department of Urology, King Fahd Armed Forces Hospital, Jeddah, KSA Flat 1, 3245 manazil aleuzama’ street, Ar Ruwais Dist, Jeddah, Saudi Arabia Postal code: 23211 Ahmed Alrefaey a7medrefa3y.ash@gmail.com Osama Shalkamy dr_shalkamy@yahoo.com Mohamed A Elhelaly elhelalymohammed@yahoo.com El-Sayed El-Agamy abuamar1978@yahoo.com Abdrabuh M Adrabuh abdo197871@yahoo.com Hany Eldamanhory drhanyeldamanhory@gmail.com Ahmed Mohamed Soliman a_soliman_1@hotmail.com Hossam A Shouman drhossamshouman@gmail.com Mohamed Shehab shehab810@gmail.com Nader A Abdelkhalek doctornader2@gmail.com Ahmed Shafiea shafieaahmed2018@yahoo.com Mohamed Elsalhy drsalhy2020@gmail.com Department of Urology, Faculty of Medicine, Al-Azhar University, Cairo, Egypt Tamer Ewida tamereweda@yahoo.com Urology Department, Blackpool teaching hospital, Blackpool, UK Maged Kamal Fayad National Institute of Urology and Nephrology, Cairo, Egypt Hamada Ahmed Yousef hay02@fayoum.edu.eg Department of Urology, Faculty of Medicine, Fayoum University, Fayoum, Egypt