Infectious Complications, Healthcare Resource Use, and Medical Costs Associated with Delays in Percutaneous Nephrolithotomy Among Patients with Stone Disease and Ureteral Stent Placement.

Purpose: The relationship between ureteral stent duration before percutaneous nephrolithotomy (PCNL) and infectious complications, admissions, imaging, and medical costs was evaluated. Materials and Methods: Patients who underwent PCNL within 6 months of ureteral stent placement were identified from commercial claims, categorized by time to treatment (0-30, 31-60, and >60 days), and followed 1-month post-PCNL. The effect of delayed treatment on inpatient admissions, infectious complications (pyelonephritis/sepsis), and imaging utilization was evaluated with logistic regression. A generalized linear model evaluated the effect of delayed treatment on medical costs. Results: Among 564 patients with PCNL and meeting the inclusion criteria (mean age 50; 55% female; 45% from South), mean (standard deviation) time to surgery was 48.8 (41.8) days. Less than half (44.3%; n = 250) underwent PCNL within 30 days of ureteral stent placement, 27.0% (n = 152) between 31 and 60 days, and 28.7% (n = 162) >60 days. Time to PCNL was significantly associated with inpatient admissions (>60 vs ≤30 days odds ratio [OR] 1.97, 95% confidence interval [CI] 1.29-3.01, p = 0.0016), infectious complications (>60 vs ≤30 days OR 2.43, 95% CI 1.55-3.81, p = 0.0001), imaging utilization (31-60 vs ≤30 days OR 1.56, 95% CI 1.02-2.38, p = 0.0383; >60 vs ≤30 days OR 2.01, 95% CI 1.31-3.06, p = 0.0012), and medical costs (31-60 vs ≤30 days OR 1.27, 95% CI 1.08-1.49, p = 0.0048; >60 vs ≤30 days OR 1.46, 95% CI 1.24-1.71, p < 0.0001). Conclusions: Compared with PCNL within 30 days, patients undergoing PCNL >30 days after ureteral stent placement had increased likelihood of infectious complications, resource use, and medical costs. These results may inform health care resource utilization and PCNL prioritization.

Prevalence of Stone Disease and Procedure Trends in the United States.

OBJECTIVE: To evaluate the prevalence of stone disease and procedure trends among US commercial and Medicare populations. METHODS: Retrospective analyses for a US commercial population and Medicare population were conducted using the Merative MarketScan Commercial Database and Medicare Standard Analytic File (5% sample), respectively. Patients aged 18+ were included if they had an encounter in any setting with a primary stone diagnosis or stone procedure (ureteroscopy [URS], percutaneous nephrolithotomy (PCNL), or shockwave lithotripsy [SWL]) between 2011 and 2019. Analyses were conducted at the patient level. RESULTS: Over the study time horizon, the prevalence of stone disease showed a small yet statistically significant decrease in the commercial population (1.04%-1.01%; P.ß<.ß0.0001) and a statistically significant increase in the Medicare population (1.84%-2.34%; P.ß<.ß0.0001). URS.ßprocedure volumes increased by 22.6% (P.ß<.ß0.0001) in the commercial population and by 56.6% (P.ß<.ß0.0001) in the Medicare population over the study period. Similarly, PCNL.ßprocedure volumes increased by 17.4% (P.ß<.ß0.0001) in the commercial population and 27.5% (P.ß<.ß0.0001) in the Medicare population. Procedure volumes for SWL decreased by 26.9% in the commercial population (P.ß<.ß0.0001) and by 3.8% in the Medicare population although the results were not statistically significant. CONCLUSION: The prevalence of stone disease showed a small decrease in the US commercial population and an increase in the Medicare population over the study time horizon. In both populations, increasing procedure volumes were observed for URS and PCNL while decreasing volumes were observed for SWL.

Delays in Ureteroscopy and Shockwave Lithotripsy After Ureteral Stent Placement: Impact on Infectious Complications, Resource Use, and Medical Costs.

Purpose: To evaluate the effects of ureteral stent duration before ureteroscopy (URS) or extracorporeal shockwave lithotripsy (SWL) on infectious complications, health care resource utilization (HCRU), and costs. Materials and Methods: Patients who underwent URS/SWL within 6months of ureteral stent placement were identified from commercial claims, categorized by time from stent placement to URS (0-15, 16-30, 31-60, and >60 days) or SWL (0-15, 16-30, and >30 days), and followed 1-month postprocedure. The relationship between ureteral stent duration and emergency department (ED) visits, inpatient admissions, infectious complications (pyelonephritis/sepsis), imaging, and costs was evaluated. Results: Mean time to URS (n = 9276 patients) was 21.3 ± 24.4 days and SWL (n = 4689 patients) was 19.0 ± 24.8 days. Compared with patients who underwent URS within 15 days of ureteral stent placement, URS 31 to 60 days after ureteral stent placement was significantly associated with inpatient admissions (odds ratio [OR] 2.56, 95% confidence interval [CI] 2.03-3.22); infectious complications (OR 2.82, 95% CI 2.09-3.81); imaging (OR 2.12, 95% CI 1.82-2.46); and medical costs (OR 1.49, 95% CI 1.40-1.58). Compared with patients who underwent SWL within 15 days of ureteral stent placement, SWL more than 30 days after ureteral stent placement was significantly associated with ED visits (OR 1.79, 95% CI 1.37-2.34); inpatient admissions (OR 3.34, 95% CI 2.38-4.69); infectious complications (OR 3.54, 95% CI 2.20-5.70); imaging (OR 2.65, 95% CI 2.23-3.15); and medical costs (OR 1.45, 95% CI 1.36-1.54). Conclusions: URS or SWL >30 days after ureteral stent placement increased the likelihood of infectious complications, HCRU, and medical costs.

Use of the Quick Sequential Organ Failure Assessment Score for Prediction of Intensive Care Unit Admission Due to Septic Shock after Percutaneous Nephrolithotomy: A Multicenter Study.

PURPOSE: Recent studies have demonstrated that quick sequential organ failure assessment criteria may be more accurate than systemic inflammatory response syndrome criteria to predict postoperative sepsis. In this study we evaluated the ability of these 2 criteria to predict septic shock after percutaneous nephrolithotomy. MATERIALS AND METHODS: We performed a retrospective multicenter study in 320 patients who underwent percutaneous nephrolithotomy at a total of 8 institutions. The criteria for quick sequential organ failure assessment and systemic inflammatory response syndrome were collected 24 hours postoperatively. The study primary outcome was postoperative septic shock. Secondary outcomes included 30 and 90-day emergency department visits, and the hospital readmission rate. RESULTS: Three of the 320 patients (0.9%) met the criteria for postoperative septic shock. These 3 patients had positive criteria for quick sequential organ failure assessment and systemic inflammatory response syndrome. Of the entire cohort 23 patients (7%) met quick sequential organ failure assessment criteria and 103 (32%) met systemic inflammatory response syndrome criteria. Specificity for postoperative sepsis was significantly higher for quick sequential organ failure assessment than for systemic inflammatory response syndrome (93.3% vs 68.4%, McNemar test p <0.001). The positive predictive value was 13% for quick sequential organ failure assessment criteria and 2.9% for systemic inflammatory response syndrome criteria. On multivariate logistic regression systemic inflammatory response syndrome criteria significantly predicted an increased probability of the patient receiving a transfusion (ß = 1.234, p <0.001). Positive quick sequential organ failure assessment criteria significantly predicted an increased probability of an emergency department visit within 30 days (ß = 1.495, p <0.05), operative complications (ß = 1.811, p <0.001) and transfusions (p <0.001). The main limitation of the study is that it was retrospective. CONCLUSIONS: Quick sequential organ failure assessment criteria were superior to systemic inflammatory response syndrome criteria to predict infectious complications after percutaneous nephrolithotomy.

A Decision Analysis of Observation vs Immediate Reintervention for Asymptomatic Residual Fragments Less than 4 mm Following Ureteroscopic Lithotripsy.

INTRODUCTION: We performed a decision analysis model of the cost-effectiveness of observation vs intervention for asymptomatic residual fragments less than 4 mm in diameter following ureteroscopic holmium laser lithotripsy. METHODS: Outcomes data from a retrospective analysis evaluating the natural history, complications and reintervention rates of asymptomatic residual stone fragments performed by the EDGE (Endourology Disease Group for Excellence) Research Consortium were used. A decision analysis model was constructed to compare the cost-effectiveness of initial observation of residual fragments to immediate intervention. Cost of observation included emergency room visits, hospitalizations and reinterventions. The cost analysis model extended to 3 years to account for delayed reintervention rates for fragments less than 4 mm. Costs of emergency department visits, readmissions and reinterventions were calculated based on published figures from the literature. RESULTS: Decision analysis modeling demonstrated that when comparing initial observation to immediate reintervention, the cost was $2,183 vs $4,424. The difference in cost was largely driven by the fact that over 3 years, approximately 55% of all patients remained asymptomatic and did not incur additional costs. This represents an approximate annual per patient savings of $747, and $2,241 over 3 years when observation is selected over immediate reintervention. CONCLUSIONS: Our decision analysis model demonstrates superior cost-effectiveness for observation over immediate reintervention for asymptomatic residual stones less than 4 mm following ureteroscopic lithotripsy. Based on these findings careful stratification and selection of patients may enable surgeons to improve cost-effectiveness of managing small, asymptomatic residual fragments following ureteroscopic lithotripsy.

Rapid kVp switching dual-energy CT in the assessment of urolithiasis in patients with large body habitus: preliminary observations on image quality and stone characterization.

PURPOSE: The purpose of this study was to investigate the image quality (IQ) considerations of rapid kVp switching dual-energy CT (rsDECT) in the assessment of urolithiasis in patients with large body habitus and to evaluate whether it allows stone characterization. MATERIALS AND METHODS: In this IRB-approved, HIPAA compliant retrospective study, 93 consecutive patients (M/F = 72/21, mean age 56.9 years, range 23-83 years) with large body habitus (> 90 kg/198 lbs) who underwent dual-energy (DE) stone protocol CT on a rapid kVp switching DECT scanner between January 2013 and December 2016 were included. Scan acquisition protocol included an initial unenhanced single-energy CT (SECT) scan of KUB followed by targeted DECT in the region of stones. Two readers evaluated both CT data sets (axial 5 mm 120 kVp/140 kVp QC/70 keV monoenergetic, material density water/iodine images and coronal/sagittal 3 mm images) for the assessment of image quality (Scores: 1-4) and characterization of stone composition (reference standard: crystallography). RESULTS: One hundred and five CT examinations were performed in 93 patients (mean body weight 105.12 ± 13.53 kg, range 91-154 kg), and a total of 321 urinary tract calculi (mean size-4.8 ± 3.2 mm, range 1.2-22 mm) were detected. Both SECT and targeted monoenergetic images were of acceptable image quality (mean IQ: 3.77 and 3.83, kappa 0.79 and 0.87 respectively). Material density water and iodine images had lower IQ scores (mean IQ: 2.97 and 3.09 respectively) with image quality deterioration due to severe photon starvation/streak artifacts in 20% (21/105) and 17% (18/105) scans, respectively. Characterization of stone composition into uric acid/non-uric acid stones was achieved in 93.14% (299/321) of calculi (mean size: 4.99 ± 3.3 mm, range 1.2-22 mm), while 7% (22/321) stones could not be characterized (mean size 3.03 ± 1.16 mm, range 1.6-6.4 mm) (p < 0.001). Most common reason for non-characterization was image quality deterioration of the material density iodine images due to severe photon starvation artifacts. On multivariate regression, stone size and patient weight were predictors of stone composition determination on DECT (p < 0.05). The transverse diameter had a weak negative correlation with stone composition determination, but it was not statistically significant. Stone characterization into uric acid vs. non-uric acid stones was accurate in 95% (n = 38/40) of stones in comparison with crystallography. CONCLUSION: In patients with large body habitus, rsDECT allowed characterization of most calculi (93%) despite image quality deterioration due to photon starvation/streak artifacts in up to 20% of material density images. Stone size and patient weight were predictors of stone composition determination on DECT, and small calculi in very large patients may not be characterized.

Assessment of readability, quality and popularity of online information on ureteral stents.

OBJECTIVE: To evaluate the quality and readability of online information on ureteral stents. METHODS: Google.com was queried using the search terms "ureteric stent", "ureteral stent", "double J stent" and, "Kidney stent" derived from Google AdWords. Website popularity was determined using Google Rank and the Alexa tool. Website quality assessment was performed using the following criteria: Journal of the American Medical Association (JAMA) benchmarks, Health on the Net (HON) criteria, and a customized DISCERN questionnaire. The customized DISCERN questionnaire was developed by combining the short validated DISCERN questionnaire with additional stent-specific items including definition, placement, complications, limitations, removal and "when to seek help". Scores related to stent items were considered as the "stent score" (SS). Readability was evaluated using five readability tests. RESULTS: Thirty-two websites were included. The mean customized DISCERN score and "stent score" were 27.1 ± 7.1 (maximum possible score = 59) and 14.6 ± 3.8 (maximum possible score = 24), respectively. A minority of websites adequately addressed "stent removal" and "when to seek medical attention". Only two websites (6.3%) had HON certification (drugs.com, radiologyinfo.org) and only one website (3.3%) met all JAMA criteria (bradyurology.blogspot.com). Readability level was higher than the American Medical Association recommendation of sixth-grade level for more than 75% of the websites. There was no correlation between Google rank, Alexa rank, and the quality scores (P > 0.05). DISCUSSION: Among the 32 most popular websites on the topic of ureteral stents, online information was highly variable. The readability of many of the websites was far higher than standard recommendations and the online information was questionable in many cases. These findings suggest a need for improved online resources in order to better educate patients about ureteral stents and also should inform physicians that popular websites may have incomplete information.

Cost-effectiveness comparison of ureteral calculi treated with ureteroscopic laser lithotripsy versus shockwave lithotripsy.

PURPOSE: To evaluate the cost-effectiveness of shockwave lithotripsy (SWL) versus ureteroscopic lithotripsy (URS) for patients with ureteral stones less than 1.5 cm in diameter. METHODS: Patient age, stone diameter, stone location, and stone-free status were recorded for patients treated with SWL or URS for ureteral stones under 1.5 cm over a 1 year period. Institutional charges were obtained from in-house billing. A decision analysis model was constructed to compare the cost-effectiveness of SWL and URS using our results and success rates for modeling. Three separate models were created to reflect differing practice patterns. RESULTS: A total of 113 patients were included-51 underwent SWL and 62 underwent URS as primary treatment. Single procedure stone-free rates for SWL and URS were 47.1 and 88.7 %, respectively (p < 0.002). Decision analysis modeling demonstrated cost-effectiveness of SWL when SWL single procedure stone-free rates (SFR) were greater than or equal to 60-64 % or when URS single procedure SFRs were less than or equal to 57-76 %, depending on practice patterns. CONCLUSIONS: This retrospective study revealed superior SFR for ureteral stones less than 1.5 cm treated with URS compared to SWL. Our decision analysis model demonstrated that when SFR for SWL is less than 60-64 % or is greater than 57-76 % for URS, SWL is not a cost-effective treatment option. Based on these findings, careful stratification and selection of stone patients may enable surgeons to increase the cost-effectiveness of SWL.

The new epidemiology of nephrolithiasis.

Historically nephrolithiasis was considered a disease of dehydration and abnormal urine composition. However, over the past several decades, much has been learned about the epidemiology of this disease and its relation to patient demographic characteristics and common systemic diseases. Here we review the latest epidemiologic studies in the field.

Cost-effectiveness comparison of renal calculi treated with ureteroscopic laser lithotripsy versus shockwave lithotripsy.

PURPOSE: To evaluate the cost-effectiveness of shockwave lithotripsy (SWL) vs ureteroscopic lithotripsy (URS) for patients with renal stones <1.5 cm in diameter. METHODS: Patient age, stone diameter, stone location, and stone-free status were recorded for patients treated with SWL or URS for renal stones <1.5 cm in maximal diameter over a 1-year period. Institutional charges were obtained from in-house billing. A decision analysis model was constructed to compare the cost-effectiveness of SWL and URS and using our results and success rates for modeling. Three separate models were created to reflect practice patterns for SWL. RESULTS: One hundred fifty-eight patients were included in the study-78 underwent SWL and 80 underwent URS as primary treatment. Single procedure stone-free rates (SFR) for SWL and URS were 55% and 95%, respectively (P<0.0001). Decision analysis modeling demonstrated cost-effectiveness of SWL when SWL single procedure SFR were 65% to 67% or when URS single procedure SFR was 72% to 84%. CONCLUSIONS: This retrospective study revealed superior SFR results for renal stones <1.5 cm for URS compared with SWL. Our decision analysis model demonstrates that for SWL SFR less than 65% to 67% or for URS SFR greater than 72% to 84%, SWL is not a cost-effective treatment option. Based on these findings, careful stratification and selection of stone patients may enable surgeons to increase the cost-effectiveness of SWL.

Ureteral stenting and retrograde pyelography in the office: clinical outcomes, cost effectiveness, and time savings.

OBJECTIVES: To examine the clinical outcomes and cost-effectiveness of endourologic procedures performed in the office using standard fluoroscopy and topical anesthesia. METHODS: We performed a retrospective review of all patients who underwent primary ureteral stent placement, ureteral stent exchange, or ureteral catheterization with retrograde pyeolography or Bacillus Calmette-Guerin (BCG) instillation under fluoroscopic guidance in the office. For an evaluation of potential time savings, we compared this to a cohort of similar procedures performed in the operating room during the same time period. RESULTS: Procedures were attempted in 65 renal units in 38 patients (13 male, 25 female) with a mean age of 62.2 years (range 29.1-95.4 years). Primary ureteral stent placement was successful in 23/24 (95.8%) renal units. Ureteral stent exchange was successful in 19/22 (86.4%) renal units. Ureteral catheterization with retrograde pyelography or BCG instillation was successful in 19/19 (100%) renal units. The total cost savings for the 38 patients in this study, including excess cost from failure in the office, was approximately $91,496, with an average cost savings of $1,551 per procedure. Office-based procedures were associated with a nearly three-fold reduction in total hospital time as a result of reduced periprocedure waiting times. CONCLUSIONS: Ureteral stent placement, ureteral stent exchange, and ureteral catheterization can be performed safely and effectively in the office in both men and women. This avoids general anesthesia and provides significant savings of time and cost for both patients and the health care system.

Insurance status, stone composition, and 24-hour urine composition.

UNLABELLED: Abstract Purpose: We examined the stone composition, 24-hour urinary risk factors, and insurance status in patients evaluated in two regional stone clinics to further investigate the relationship between the socioeconomic status and kidney stone formation. MATERIALS AND METHODS: We performed a retrospective review of stone formers who completed a 24-hour urinalysis as part of a metabolic evaluation for nephrolithiasis. Insurance status was determined by billing records and those with state-assisted insurance (SAI) were compared to patients with private insurance (PI). Multivariate analyses were performed adjusting for known risk factors for stones. RESULTS: Three hundred forty-six patients were included. Patients with SAI (16%) were significantly more likely to be female (55% vs.38%, p=0.026) and younger (43.5 vs.49.2, p=0.003). Among those with stone composition data (n=200), SAI patients were as likely to form calcium phosphate (CaPhos) as calcium oxalate (CaOx) stones (46.9% vs.31.3%, p=0.44). PI patients were significantly less likely to form CaPhos than CaOx stones (10.1% vs.77.4%, p<0.001). On multivariate analysis, among those with calcium stones, the odds of forming CaPhos stones over CaOx stones were ten times higher among SAI patients compared to PI, odds ratio 10.2 (95% CI 3.6, 28.6, p<0.001). Further, patients with SAI had significantly higher urine sodium, pH, and supersaturation of CaPhos, and a lower supersaturation of uric acid compared to patients with PI. CONCLUSIONS: SAI was associated with a greater likelihood of a CaPhos stone composition and increased urinary risk factors for CaPhos stones. These findings may reflect dietary or other unmeasured differences, and have important implications for resource allocation and counseling, as treatment may differ for these groups.

Cost-effectiveness of anti-retropulsion devices for ureteroscopic lithotripsy.

PURPOSE: We evaluated the cost-effectiveness of anti-retropulsion devices used during ureteroscopic lithotripsy. MATERIALS AND METHODS: A decision analysis model was constructed to compare the cost-effectiveness of ureteroscopic lithotripsy with vs without an anti-retropulsion device. The risk of stone retropulsion was determined from published data in the English language literature. Expected value calculations were used to determine whether the additional cost of a device would be cost-effective to prevent secondary procedures used to treat retropulsed stones. Device cost was determined using the average cost of all commercially available devices. RESULTS: It became cost-effective to use an anti-retropulsion device at or above a 6.3% retropulsion rate. The weighted probability of retropulsion with vs without an anti-retropulsion device was 98.1% vs 83.7%. The estimated costs of secondary procedures needed to treat retropulsed stones were $5,290 for shock wave lithotripsy and $6,390 for ureteroscopy. Average device cost was $278. Thus, the average additional cost of ureteroscopic lithotripsy with vs without an anti-migration device would be $384 vs $952. CONCLUSIONS: It is cost-effective to use an anti-retropulsion device at a retropulsion rate of greater than 6.3%.

Qualitative assessment of enhancement in a renal mass: contribution of subtraction CT.

PURPOSE: To evaluate the impact of subtraction CT on reader confidence and diagnostic accuracy when characterizing renal masses. MATERIALS AND METHODS: In this institutional review board-approved retrospective study, 159 patients (85 men and 74 women; mean age, 62.6 years; range, 22-88 years) underwent routine unenhanced and contrast-enhanced multidetector computed tomography (MDCT) for renal lesion characterization. Subtraction images were subsequently generated on scanner console. Two readers independently reviewed the MDCT images to characterize presence of enhancement using a 6-point scale during 3 blinded review sessions of (1) only subtraction, (2) routine, and (3) combined subtraction and routine images. The standard of reference consisted of either histopathology or follow-up imaging and clinical data. RESULTS: Of the 240 lesions evaluated, 60 lesions (mean, 3.2 cm; range, 1-7.5 cm) were enhancing and 180 lesions (mean, 2.7 cm; range, 0.5-12 cm) were nonenhancing. For determination of lesion enhancement, a combined evaluation of routine MDCT and subtraction images improved reader confidence in 60% to 63% of lesions (P < 0.001). The combined evaluation also provided the highest sensitivity (97%), specificity (99%), and accuracy (98.9%). CONCLUSION: When used in combination with routine image interpretation, subtraction CT improves reader confidence and diagnostic accuracy in identifying enhancement in renal lesions.