A comparison between asymptomatic and symptomatic ureteral stones

www.nature.com/scientificreports OPEN A comparison between asymptomatic and symptomatic ureteral stones Tae Il Noh 1, Jong Hyun Pyun 2, Ji Sung Shim 1, Seok Ho Kang 1, Jun Cheon 1 & Sung Gu Kang 1* To investigate the characteristics and impact of asymptomatic (silent) ureteral stones on renal function and compare them with those of symptomatic stones. We retrospectively reviewed the medical records of 677 patients who underwent ureteroscopic lithotripsy or laparoscopic ureterolithotomy for ureteral stones between 2016 and 2020. Patients were divided into two groups according to the presence of recognizable symptoms. We investigated the characteristics and impact of silent stones on post-treatment renal function recovery and compared them with those of symptomatic stones. Among the 677 patients, 43 (6.4%) had asymptomatic ureteral stones, and 634 (93.6%) had symptomatic ureteral stones. Compared to symptomatic stones, asymptomatic stones were larger (11.4 mm vs. 9.6 mm, p = 0.003), more commonly present in the upper ureter (62.7% vs. 48.0%, p = 0.04), and more commonly associated with high-grade hydronephrosis (32.8% vs. 12.3%, p < 0.001); however, no difference in metabolite composition was observed between the two group of stone. In the asymptomatic stone group, the mean preoperative estimated glomerular filtration rate (eGFR) was 77.37 ± 23.54 mL/min/1.73 m2, and the mean postoperative eGFR indicated no significant improvement at 1 day, 7 days, 3 months, and 12 months (76.66 ± 21.45, 77.89 ± 20.87, 77.29 ± 22.22, and 76.71 ± 24.21 mL/min/1.73 m2, respectively; p = 0.567, p = 0.613, p = 0.924, and p = 0.202, respectively). In the symptomatic stone group, the mean preoperative eGFR was 78.17 ± 28.25 mL/ min/1.73 m2; the mean postoperative eGFRs at 1 day, 7 days, 3 months, and 12 months were 81.24 ± 26.38, 86.16 ± 25.61, 89.11 ± 25.43, and 89.50 ± 26.01 mL/min/1.73 m2, respectively and demonstrated significant improvement (p = 0.002, p < 0.001, p < 0.001, and p < 0.001, respectively). Silent stones irreversibly impaired renal function, even after proper management. Therefore, active treatment strategies are required for all patients who are hesitant to receive treatment for silent stones because of their asymptomatic status to prevent permanent renal impairment. Ureterolithiasis is one of the most common urologic diseases worldwide, and the prevalence of stone disease has increased steadily due to changes in diet and lifestyle1–3. Ureteral stones usually present with acute symptoms because of urinary tract obstruction. Possible symptoms of urinary calculi include acute or chronic flank pain, hematuria, and symptoms related to urinary tract infection such as dysuria, frequency, and fever4. Additionally, without proper treatment, obstructive uropathy caused by calculi can occasionally lead to permanent renal dysfunction5. Asymptomatic (silent) stones in the renal collecting system are diagnosed frequently by ultrasonography and abdominal non-contrast computed tomography (CT) during regular health check-ups. Their impact and natural course have been thoroughly discussed6,7. Owing to the development of endoscopic equipment, diagnosed asymptomatic stones in the collecting system have been treated relatively easily; however, studies on the impact and natural course of asymptomatic (silent) stones in the ureter have been overlooked and n eglected8,9. Although several studies focusing on the influence of silent stones on renal function have been reported, studies comparing silent and symptomatic ureteral stones are r are10. In this study, we aimed to investigate the characteristics and impact of silent stones on renal function recovery after proper treatment by comparing the cases of asymptomatic and symptomatic ureteral stones, which were treated during the same period and single center. 1 Department of Urology, Anam Hospital, Korea University College of Medicine, 73, Goryeodae‑Ro, Seongbuk‑Gu, Seoul 02841, Korea. 2Department of Urology, Sungkyunkwan University School of Medicine, Seoul, Republic of Korea. *email: Scientific Reports | (2023) 13:2757 | https://doi.org/10.1038/s41598-023-29866-5 1 Vol.:(0123456789) www.nature.com/scientificreports/ Materials and methods Study design. We retrospectively reviewed the medical records of 677 patients who underwent endoscopic surgery such as ureteroscopic lithotripsy and laparoscopic ureterolithotomy for ureteral stones between 2016 and 2020. Patients who underwent medical expulsive therapy (MET), extracorporeal shock wave lithotripsy, percutaneous nephrolithotomy, or retrograde intrarenal surgery were excluded from the study in order to assess the course of renal function recovery without any interference from the associated effects of kidney stones or surgical methods. According to the presence of recognizable symptoms such as pain, gross hematuria, and urinary tract infection, patients were divided into two groups: symptomatic and asymptomatic stone groups. In addition, we included that there were no symptoms at the time of diagnosis. Although initial stone related symptoms were reported, they were ignored; hence, we did not find any symptoms at the timing of diagnosis. All the patients in the symptomatic stone group received surgical treatment because of persistent pain or when the spontaneous passage of stones was unlikely to occur over 3 weeks, particularly ureteroscopic lithotripsy for stones > 6 mm and laparoscopic ureterolithotomy for stones > 20 mm11. Likewise, patients with silent ureteral stones underwent surgical treatment with the same indications for symptomatic stones except the stone-related symptoms. We compared the findings of metabolic analysis and urinary analysis, the size and location of stone, and the grade of hydronephrosis evaluated by CT scan between the two groups. To investigate renal function recovery, we evaluated the differences between the preoperative estimated glomerular filtration rate (eGFR) and 1-day, 7-day, 3-month, and 12-month postoperative values of eGFR and we compared these differences between the two groups (Fig. 1). The eGFR values were calculated based on the Chronic Kidney Disease Epidemiology Collaboration (CKDEPI) equation using serum creatinine levels as follows: 141 × min(SCr/κ,1)α × max(SCr/κ,1) −1.209 × 0.993age × 1.018 [if female] × 1.159 [if African American], where κ is 0.7 for female patients and 0.9 for male patients; α is − 0.329 for female patients and − 0.411 for male patients; min indicates the minimum of SCr/κ or 1 and max indicates the maximum of SCr/κ or 1. To monitor the change in hydronephrosis, we performed serial low-dose CT scan at 3 months and 12 months postoperatively. Statistical analysis. Demographic and clinical variables were summarized using descriptive statistics. Continuous variables are presented as mean (standard deviation). Independent and paired t-tests were performed to compare mean values between the two groups. The Shapiro–Wilk test (...truncated)