Economics of stone management

Economic Burden of Imaging and Interventions in Endourology: A Worldwide Cost Analysis from European Association of Urology Young Academic Urology Endourology and Urolithiasis Working Party

Background and Objective: The cost of imaging and interventions in the surgical field varies between countries and sometimes within different regions of the same country. Procedural cost takes into account equipment, consumables, operating room, surgical, anesthetic and nursing teams, radiology, medications, and hospital stay. Health care systems therefore face an incredible burden related to investigations and surgical procedures. The aim of this study was to collect costs of imaging and interventions for kidney calculi across different hospitals and health care systems in the world. Methods: An online shared Google spreadsheet was created by the European Association of Urology Young Academic Urology urolithiasis group. The survey consisted of the cost of four radiological imaging (ultrasound of the urinary tract [USS], plain X-ray radiography of the abdomen including kidneys, ureter, and bladder [XRKUB], noncontrast-enhanced computerized tomography [CTKUB], and contrast-enhanced CT with urographic phase [CTU]) and seven interventions (endoscopic laser treatment of renal stones, ureteroscopic treatment or extraction of ureteral stones, percutaneous nephrolithotomy (PCNL), insertion of ureteral stent, diagnostic ureteroscopy, and cystolitholapaxy). A chosen representative from each country collected and collated the data, and this was converted to Euros (€). Key Findings and Limitations: Data were collected from 32 countries, which include Turkey, Armenia, Nepal, Uzbekistan, Brazil, Chile, Qatar, Peru, Israel, Singapore, Thailand, Colombia, Argentina, Saudi Arabia, Asia, North America, 15 countries from the European continent, and the United States. The mean cost of USS, XRKUB, CTKUB, and CTU was 51.3 € (range: 2-160 €), 27.1 € (range: 2.5-187 €), 105.8 € (range: 19-405 €), and 171.5 € (range: 19-674 €), respectively. Similarly, the cost of endoscopic laser treatment of renal stones, ureteroscopic treatment/extraction of ureteral stones, PCNL, insertion of ureteral stent, diagnostic ureteroscopy, and cystolitholapaxy was 1942.6 € (range: 100-7887 €), 1626.8 € (range: 80-9787 €), 2884.6 € (range: 110-12642 €), 631 € (range: 110-2787 €), 861.6 € (range: 3-2667 €), and 876 € (range: 19-3457 €), respectively. Wide differences in cost between countries were found within the study. Conclusions and Clinical Implications: This study highlights the significant economic impact of kidney stone management on health care systems worldwide. There seem to be significant disparities between costs, and this study shows the social and economic inequalities in health care access, which can differ significantly between private and public health care. These results can aid policymakers to address these disparities and perhaps to learn from other health care providers.

Trends in the Incidence and DALYs of Urolithiasis From 1990 to 2019: Results From the Global Burden of Disease Study 2019

Objectives

To provide a comprehensive assessment of the estimated burden and trend of urolithiasis at the global, regional, and national levels.

Methods

The age-standardized rates (ASRs) of the incidence and disability-adjusted life years (DALYs) of urolithiasis from 1990 to 2019 were obtained from the Global Burden of Disease Study 2019 database. Estimated annual percentage changes (EAPCs) were calculated to quantify the temporal trends in urolithiasis burden.

Results

In 2019, the ASRs of the incidence and DALYs were 1,394.03/100,000 and 7.35/100,000, respectively. The ASRs of the incidence and DALYs of urolithiasis decreased from 1990 to 2019 with EAPCs of −0.83 and −1.77, respectively. Males had a higher burden of urolithiasis than females. In 2019, the highest burden of urolithiasis was observed in regions with high–middle sociodemographic index (SDI), particularly in Eastern Europe, Central Asia, and Southeast Asia. The burden of urolithiasis increased in most countries or territories. The burden of urolithiasis and SDI had a non-linear relationship, and the estimated value of urolithiasis burden was the highest when the SDI value was ~0.7.

Conclusion

Globally, the ASRs of the incidence and DALYs of urolithiasis decreased from 1990 to 2019, but an increasing trend was observed among many countries. More effective and appropriate medical and health policies are needed to prevent and early intervene in urolithiasis.

Comparison of scoring systems for predicting stone-free status and complications after retrograde ıntrarenal surgery

PURPOSE

To compare the effectiveness of scoring systems in predicting stone-free rates (SFR) and complications following retrograde intrarenal surgery (RIRS).

MATERIALS AND METHODS

We retrospectively analyzed 280 patients who underwent RIRS for kidney stones between 2016 and 2019. The Resorlu-Unsal Stone score (RUSS), Modified Seoul National University Renal Stone Complexity (S-ReSC) score, and R.I.R.S. scoring system score were calculated for each patient who was enrolled in the study. Subsequently, stone scoring systems were compared as to their predictive capability for SFR using receiver-operating characteristic curves. Furthermore, multivariate analysis was done to determine whether the scoring systems associated with SFR and complications.

RESULTS

The median patient age was 44 (35--56). The median RUSS, S-ReSC, and R.I.R.S scores were 0 (0-1), 1(1-2), and 6 (5-7), respectively. The overall SFR was 76.7%. The R.I.R.S. scoring system was found to have a higher predictive value in predicting postoperative SFR than the other two scoring systems (p < 0.001, AUC = 0,816). RUSS, R.I.R.S. score, and stone size were found to be independent predictive factors for SFR (p = 0.049, p = 0.024, p = 0.033, respectively). Complications were observed in 3.2%(9/280) of patients. Stone scoring systems were not statistically associated with complications. Operation duration was the only independent risk factor for complications (p = 0.010).

CONCLUSIONS

The R.I.R.S. scoring system was found to have a higher predictive value than RUSS and S-ReSC to predict SFR following RIRS in our study. However, none of the stone scoring systems was directly proportional to complications of RIRS.

Percutaneous nephrolithotomy versus shock wave lithotripsy for high-density moderate-sized renal stones: A prospective randomized study

Context:

The management of renal stones of high density (>1000 Hounsfield units) on non-contrast computed tomography (NCCT), and moderate sized (15-25 mm) is still debatable.

Aims:

The aim of this study was to compare the outcomes of percutaneous nephrolithotomy (PCNL) and shock wave lithotripsy (SWL) for the high-density and moderate-sized renal stones regarding the stone-free rate (SFR), morbidity, and patients' quality of life.

Settings and Design:

This is a prospective randomized study.

Patients and Methods:

Eighty consecutive patients with renal stones, excluding those with lower calyceal stones, were randomized to receive either PCNL or SWL (40 in each arm). Patients were followed up by abdominal ultrasound and plain X-ray (NCCT if indicated) till clearance of stone. Outcomes, complications, costs, and SF-8 Health Survey scoring were recorded for each group.

Statistical Analysis:

We used Stata software, version 9.2 (Intercooled STATA®; StataCorp LP College Station, Texas, USA). Comparison of the two groups was made with regard to patient and stone criteria and the procedure details. Continuous variables were compared using the Mann–Whitney U-test with values shown as the median and interquartile range. Categorical variables were compared using the Pearson's Chi-square/Fisher's exact test. Multivariate logistic regression analysis was used to identify variables independently associated with the stone clearance after two sessions of SWL. P < 0.05 was considered statistically significant.

Results:

The basic characteristics of both groups were comparable. After a single treatment session, the SFR was 80% and 27.5% for PCNL and SWL, respectively (P < 0.001). The overall 3-month SFR was 87.5% versus 90%, respectively (P = 0.723). The median number of the required maneuvers was 1 (range: 1–3) for PCNL versus 2 (range: 1–4) for SWL (P < 0.001). The complication rate was 10% and 7.5%, respectively (P = 0.692). The cost of SWL was significantly lower (P < 0.001). On multivariate analysis, a single stone was an independent predictor for stone clearance after two sessions of SWL (odds ratio: 7.26, 95% confidence interval: 1.13–46.62, P = 0.037).

Conclusions:

PCNL for the dense, and moderate-sized renal stone provides higher initial success and lower re-treatment rates compared with SWL with comparable outcome after 3 months of therapy. However, SWL is an alternative, especially for a single stone.

Costs variations for percutaneous nephrolithotomy in the U.S. from 2003-2015: A contemporary analysis of an all-payer discharge database

INTRODUCTION

We sought to evaluate population-based costs variations and predictors of outlier costs for percutaneous nephrolithotomy (PCNL) in the U.S.

METHODS

Using the Premier Healthcare Database, we identified all patients diagnosed with kidney/ureter calculus who underwent PCNL from 2003-2015. We evaluated 90-day direct hospital costs, defining high- and low-cost surgery as those >90th and <10th percentile, respectively. We constructed a multilevel, hierarchical regression model and calculated the pseudo-R² of each variable, which translates to the percentage variability contributed by that variable on 90-day direct hospital costs.

RESULTS

A total of 114 581 patients underwent PCNL during the 12-year study period. Mean cost in the low-cost group was $5787 (95% confidence interval [CI] 5716-5856) vs. $38 590(95% CI 37 357-39 923) in the high-cost group. Cost variations were substantially impacted by patient (63.7%) and surgical (18.5%) characteristics and less so by hospital characteristics (3.9%). Significant predictors of high costs included more comorbidities (≥2 vs. 0: odds ratio [OR] 1.81; p=0.01) and hospital region (Northeast vs. Midwest: OR 2.04; p=0.03). Predictors of low cost were hospital bed size of 300-499 beds (OR 1.35; p<0.01) and urban hospitals (OR 2.77; p=0.01). Factors less likely to be associated with low-cost PCNL were more comorbidities (Charlson Comorbidity Index [CCI] ≥2: OR 0.69; p<0.0001), larger hospitals (OR 0.61; p=0.01), and teaching hospitals (OR 0.33; p<0.0001).

CONCLUSIONS

Our contemporary analysis demonstrates that patient and surgical characteristics had a significant effect on costs associated with PCNL. Poor comorbidity status contributed to high costs, highlighting the importance of patient selection.

Metabolic evaluation guidelines in patients with nephrolithiasis: Are they being followed? Results of a national, multi-institutional, quality-assessment study

INTRODUCTION

The significant cost burden of kidney stones underscores the importance of best clinical practice in kidney stone management. We evaluated adherence to kidney stone metabolic evaluation guidelines in a Canadian population and the interest of patients with regard to prevention.

METHODS

A questionnaire based on Canadian Urological Association (CUA) best practice guidelines was designed. Patients presenting for extracorporeal shockwave lithotripsy treatment (ESWL) were administered this questionnaire to evaluate risk factors of stone disease and assess the use of metabolic evaluations. Patients were asked if they received explanations about their results and if they were interested in kidney stone prevention.

RESULTS

We identified 530 patients at five academic institutions; 79.4% had at least one indication to receive a metabolic evaluation (high-risk stone formers), which increased to 96.6% if first-time stone formers whom reported an interest in metabolic evaluation were included. However, only 41.1 % of these patients had a metabolic evaluation. Endourologists ordered metabolic evaluation more often than other referring urologists (63.6% vs. 36.5%; p<0.001). Furthermore, urologists ordered metabolic evaluations more often than other prescribing physicians (68.9% vs. 31.1%; p<0.001). Sixty-two percent of patients received explanations about their metabolic evaluation results and 77.5% understood them. Regarding prevention, 84.1% and 83.8% were interested in more explanations and in following a diet or taking a medication, respectively.

CONCLUSIONS

Adherence to CUA metabolic evaluation guidelines is suboptimal and could be improved by urologists referring patients for ESWL. Communication between physician and patient may not be adequate. The majority of stone formers are interested in kidney stone prevention.

Incorporation of the fluoroless C-Arm Trainer at the American Urological Association hands on training percutaneous renal access

OBJECTIVES

To assess for usefulness and validity evidence for incorporating the C-Arm Trainer (CAT) simulator into the annual AUA hands on course for training percutaneous nephrolithotomy (PCNL).

MATERIALS AND METHODS

The course started with a didactic session followed by four stations for training the "bull's eye" technique using the CAT simulator. Each station included a pre-test, 30-min practice on the simulator, and post-test. All participants were assessed using a 4-item checklist. All participants were asked to fill in a qualitative self-assessment questionnaire after the pre- and the post-test, and respond to a course evaluation questionnaire and post-course survey.

RESULTS

A total of 38 physicians, who attended the hands on course, voluntarily participated in the study. Only 21.1% had previous practice on PCNL simulators. Compared with the results of the checklist total score and the qualitative self-assessment questionnaire scores after the pre-test, there was significant improvement in the checklist total score (p < 0.001), temporal demands (p = 0.003), situational stress (p = 0.003, and performance (0.003) after the post-test. A total of 14 (36%) participants responded to the course evaluation questionnaire, 50% evaluated the course as excellent, 28.6% as very good, and 21.4% as good. Unfortunately, only five (13%) participants responded to the post-course survey, 4/5 implemented the new competencies and knowledge into their practice, and 3/5 have attempted to obtain fluoroscopic guided PCA without assistance.

CONCLUSION

The CAT simulator was considered useful for training the percutaneous renal access procedure. There was significant improvement in the qualitative and quantitative assessment parameters after the post-test compared with the pre-test.

Shifting the Split Reflectors to Enhance Stone Fragmentation of Shock Wave Lithotripsy

Shock wave lithotripsy (SWL) has been used widely in urology for about three decades to treat kidney calculi. Technical development to improve performance (i.e., stone fragmentation efficiency) is continuous. Low-pressure wide-focus lithotripters have already achieved promising results. In this study, the lithotripter field and profile of lithotripter shock waves were changed simultaneously using a cost-effective and convenient design. An intact parabolic reflector was split into four pieces, and each part was moved individually. By shifting the split reflectors, the focused acoustic beams were separated. As a result, the beam width in the focal region could be increased. Both numerical models of wave propagation using a k-wave approach and hydrophone measurements showed similar pressure waveforms at the focus and the distributions along and transverse to the lithotripter axis. The increase of the shifting distance from 0 mm to 7 mm resulted in the increase of -6 dB beam width from 7.1 mm to 13.9 mm and location of tensile peak on axis moving from z = -14 mm to 1 mm. The Lithotripters at 10 kV (intact reflector) and at 12 kV with the split reflectors shifted by 5 mm were compared with each other because of their similar peak positive pressures at the focus (8.07 MPa ± 0.05 MPa vs. 7.90 MPa ± 0.11 MPa, respectively). However, there were significant differences in their positive beam width (8.7 mm vs. 10.2 mm), peak negative pressure (-6.34 MPa ± 0.04 MPa vs. -7.13 MPa ± 0.13 MPa), the maximum tensile stress (7.55 MPa vs. 8.95 MPa) and shear stress (6.1 MPa vs. 7.76 MPa) in a 10-mm diameter spherical stone and bubble collapse time (127.6 μs ± 5.4 μs vs. 212.7 μs ± 8.2 μs). As a result, stone fragmentation efficiency was enhanced about 1.8-fold (57.9% ± 4.6% vs. 32.2% ± 5.6%, p < 0.05) when shifting the split reflectors. These results suggest that this new reflector design could change the characteristics of the lithotripter field and increase stone fragmentation efficiency.

Oral dissolution therapy for radiolucent kidney stones. An old treatment revisited

Objective:

We present our experience using oral bicarbonate as a dissolution therapy for radiolucent kidney stones in the pre-dual energy CT era.

Methods:

A retrospective analysis of dissolution therapy was undertaken over a four-year period. Stones were diagnosed as radiolucent on conventional KUB X-ray in combination with either ultrasound or CT KUB. Oral bicarbonate was given at a dose of 2 g tds orally, increased to 2 g five times daily according to urinary pH. Patients monitored their own urine dipstick daily to achieve a pH of at least seven.

Results:

Altogether 27 patients were identified with radiolucent stones. Stone size varied from 4–40 mm. Average length of therapy was nine weeks. Of the patients, 17 had renal U/S and six had CT KUB as end point imaging. We found that 39% had complete dissolution, 18% had a partial response and 43% showed no response. A high serum uric acid level correlated with a higher incidence of dissolution. Cost-benefit analysis shows bicarbonate therapy to be more cost-effective than lithotripsy, ureteroscopy or nephrolithotomy.

Conclusions:

Bicarbonate therapy remains an attractive option for the treatment of radiolucent kidney stones. The presence of hyperuricaemia or hyperuricosuria appears to influence the success rate. Further prospective randomised studies are needed to identify the most tolerable and effective treatment regime as well as the optimal duration of treatment. Dual-energy CT may hold the key to identifying patients most likely to benefit from treatment.

Economic impact of urinary stones

Kidney stones have been rising in prevalence in the United States and worldwide, and represent a significant cost burden. Cost effectiveness research in this area may enable improvements in treatment efficiency that can benefit patients, providers and the healthcare system. There has been limited research in the cost effectiveness of surgical interventions for stone disease, despite the diverse treatment approaches that are available. Medical expulsive therapy (MET) has been shown to improve rates of stone passage for ureteral stones, and there is evidence that this practice should be liberalized from the standpoint of both clinical and cost effectiveness. While conservative treatment following a primary stone event appears to be cost effective, the economic impact of medical therapy for recurrent stone formers requires clarification despite its clinical efficacy. Future study regarding the cost effectiveness of prevention and interventions for stone disease are likely to improve both the quality and efficiency of care.

Percutaneous nephrolithotomy vs. extracorporeal shockwave lithotripsy for treating a 20-30 mm single renal pelvic stone

Objective

To compare the efficacy, safety and cost of extracorporeal shockwave lithotripsy (ESWL) and percutaneous nephrolithotomy (PNL) for treating a 20–30 mm single renal pelvic stone.

Patients and methods

The computerised records of patients who underwent PNL or ESWL for a 20–30 mm single renal pelvic stone between January 2006 and December 2012 were reviewed retrospectively. Patients aged <18 years who had a branched stone, advanced hydronephrosis, a solitary kidney, anatomical renal abnormality, or had a surgical intervention within the past 6 months were excluded. The study included 337 patients with a mean (SD, range) age of 49.3 (12.2, 20–81) years. The patients’ criteria (age, sex, body mass index) and the stone characteristics (side, stone length, surface area, attenuation value and skin-to-stone distance) were compared between the groups. The re-treatment rate, the need for secondary procedures, success rate, complications and the total costs were calculated and compared.

Results

In all, 167 patients were treated by ESWL and 170 by PNL. The re-treatment rate (75% vs. 5%), the need for secondary procedures (25% vs. 4.7%) and total number of procedures (three vs. one) were significantly higher in the ESWL group (P < 0.001). The success rate was significantly higher in the PNL group (95% vs. 75%, P < 0.001), as was the complication rate (13% vs. 6.6%, P = 0.050). The total costs of primary and secondary procedures were significantly higher for PNL (US$ 1120 vs. 490; P < 0.001).

Conclusions

PNL was more effective than ESWL for treating a single renal pelvic stone of 20–30 mm. However, ESWL was associated with fewer complications and a lower cost.

Comparison of extracorporeal shock wave lithotripsy running models between outsourcing cooperation and rental cooperation conducted in Taiwan

BACKGROUND/PURPOSE

We conducted a retrospective study to compare the cost and effectiveness between two different running models for extracorporeal shock wave lithotripsy (SWL), including the outsourcing cooperation model (OC) and the rental cooperation model (RC).

METHODS

Between January 1999 and December 2005, we implemented OC for the SWL, and from January 2006 to October 2011, RC was utilized. With OC, the cooperative company provided a machine and shared a variable payment with the hospital, according to treatment sessions. With RC, the cooperative company provided a machine and received a fixed rent from the hospital. We calculated the cost of each treatment session, and evaluated the break-even point to estimate the lowest number of treatment sessions to make the balance between revenue and cost every month. Effectiveness parameters, including the stone-free rate, the retreatment rate, the rate of additional procedures and complications, were evaluated.

RESULTS

Compared with OC there were significantly less treatment sessions for RC every month (42.6±7.8 vs. 36.8±6.5, p=0.01). The cost of each treatment session was significantly higher for OC than for RC (751.6±20.0 USD vs. 684.7±16.7 USD, p=0.01). The break-even point for the hospital was 27.5 treatment sessions/month for OC, when the hospital obtained 40% of the payment, and it could be reduced if the hospital got a greater percentage. The break-even point for the hospital was 27.3 treatment sessions/month for RC. No significant differences were noticed for the stone-free rate, the retreatment rate, the rate of additional procedures and complications.

CONCLUSION

Our study revealed that RC had a lower cost for every treatment session, and fewer treatment sessions of SWL/month than OC. The study might provide a managerial implication for healthcare organization managers, when they face a situation of high price equipment investment.

Estimating the nationwide, hospital based economic impact of pediatric urolithiasis

PURPOSE

The incidence of urolithiasis is increasing in children and adolescents but the economic impact of this problem is unclear. We examined 2 large databases to estimate the nationwide economic impact of pediatric urolithiasis.

MATERIALS AND METHODS

We analyzed the 2009 NEDS and KID, used ICD-9-CM codes to identify children 18 years or younger diagnosed with urolithiasis and abstracted demographic and charge data from each database.

RESULTS

We identified 7,348 weighted inpatient discharges in KID and 33,038 emergency department weighted encounters in NEDS. Of the patients 32% and 36% were male, respectively. Inpatients were younger than those who presented to the ED (mean age 13.9 vs 15.7 years). Most patients had private insurance (52.9% to 57.2%) and the South was the most common geographic region (39.5% to 44.4%). The most common procedures were ureteral stent placement in 20.4% to 24.1% of cases, followed by ureteroscopy in 3.8% to 4.4%. Median charges per admission were $13,922 for a weighted total of $229 million per year. Median emergency department charges were $3,991 per encounter for a weighted total of $146 million per year.

CONCLUSIONS

Each day in 2009 in the United States an estimated 20 children were hospitalized and 91 were treated in the emergency department for upper tract stones. A conservative estimate of 2009 annual charges related to pediatric urolithiasis in the United States is at least $375 million. This is likely a significant underestimate of the true economic burden of pediatric urolithiasis because it accounts for neither outpatient management nor indirect costs such as caregiver time away from work.

Impact of stone disease: chronic kidney disease and quality of life

This article reviews the impact of stone disease on chronic kidney disease and renal function; evaluating the natural progression of disease as well as the impact of surgical interventions. The impact of stone disease, medical therapy, and surgical therapy for stones on quality of life is discussed.

Cost-effectiveness treatment strategies for stone disease for the practicing urologist

Kidney stone disease is rising in prevalence in the United States and abroad, and the cost burden of this condition is substantial. Although cost-effectiveness considerations are typically made by policymakers, individual practitioners have become increasingly involved in these discussions, to affect the rising costs of care and to assert control of treatment options. This article reviews existing literature regarding the cost-effectiveness of medical and surgical treatments for stone disease and identifies areas in which additional investigation is needed.

Economic outcomes of treatment for ureteral and renal stones: a systematic literature review

PURPOSE

We evaluated the cost-effectiveness of ureteral/renal stone treatment by comparing ureteroscopy, extracorporeal shock wave lithotripsy and percutaneous nephrolithotomy.

MATERIALS AND METHODS

We performed a systematic literature search to identify studies of treatment for adults with ureteral and renal stones that were published between 1995 and 2010. For inclusion in analysis studies had to provide the stone-free rate and the cost of at least 2 therapies.

RESULTS

Ten studies were identified, including 8 with an observational design and 2 that synthesized data using decision modeling techniques. Five of 6 studies, including 1 of 2 from the United States, compared ureteroscopy vs shock wave lithotripsy for proximal stones and showed a higher stone-free rate and lower cost for ureteroscopy. Four of the 5 studies, including the only American study, compared ureteroscopy vs shock wave lithotripsy for distal ureteral stones and also showed such an economically dominant result. Studies of shock wave lithotripsy vs percutaneous nephrolithotomy and ureteroscopy vs percutaneous nephrolithotomy for renal stones demonstrated higher cost and a higher stone-free rate for percutaneous nephrolithotomy.

CONCLUSIONS

Despite the great heterogeneity and limited quality of available cost-effectiveness evaluations most studies demonstrated that ureteroscopy was more favorable than shock wave lithotripsy for ureteral stones in stone-free rate and cost.

Chronic kidney disease in kidney stone formers

Recent population studies have found symptomatic kidney stone formers to be at increased risk for chronic kidney disease (CKD). Although kidney stones are not commonly identified as the primary cause of ESRD, they still may be important contributing factors. Paradoxically, CKD can be protective against forming kidney stones because of the substantial reduction in urine calcium excretion. Among stone formers, those with rare hereditary diseases (cystinuria, primary hyperoxaluria, Dent disease, and 2,8 dihydroxyadenine stones), recurrent urinary tract infections, struvite stones, hypertension, and diabetes seem to be at highest risk for CKD. The primary mechanism for CKD from kidney stones is usually attributed to an obstructive uropathy or pyelonephritis, but crystal plugs at the ducts of Bellini and parenchymal injury from shockwave lithotripsy may also contribute. The historical shift to less invasive surgical management of kidney stones has likely had a beneficial impact on the risk for CKD. Among potential kidney donors, past symptomatic kidney stones but not radiographic stones found on computed tomography scans were associated with albuminuria. Kidney stones detected by ultrasound screening have also been associated with CKD in the general population. Further studies that better classify CKD, better characterize stone formers, more thoroughly address potential confounding by comorbidities, and have active instead of passive follow-up to avoid detection bias are needed.

Randomized prospective trial comparing immediate versus delayed ureteroscopy for patients with ureteral calculi and normal renal function who present to the emergency department

PURPOSE

To compare the safety and efficacy of emergency vs scheduled ureteroscopy with a prospective study that included patients who presented to the emergency department (ED) with renal colic from ureteral stones.

PATIENTS AND METHODS

There were 271 consecutive patients who were enrolled in this prospective study. Patients were randomized to emergency ureteroscopy (group A) or delayed ureteroscopy (group B). All patients underwent helical unenhanced CT (HUCT). Stone-free status was defined as the complete absence of residual fragments at 1 week postoperatively, assessed with HUCT, with no need for ancillary interventions after ureteroscopy.

RESULTS

Group A included 139 assessable patients. The overall stone-free rate was 93%. Neither location nor size was a significant prognostic factor (P>0.05). Single-session ureteroscopy failed to clear nine ureteral stones. A Double-J stent was placed in 27/139 patients. Group B included 100 assessable patients. Patients in the control group were scheduled for ureteroscopy after their departure from the ED. The overall stone-free rate was 90%. Single-session ureteroscopy failed to clear 10 ureteral stones. A Double-J stent was placed in 80/100 patients. There were no statistical differences with regard to stone diameter and location, complications, and stone-free rate between group A and group B patients. The rate of Double-J stent positioning was significantly higher (P<0.05) in group B patients.

CONCLUSIONS

In our experience, emergency ureteroscopy showed equal efficacy and safety compared with the elective procedure. It has the main advantage of providing both immediate relief from pain and stone fragmentation.

Cost-effectiveness analysis of ureteroscopic laser lithotripsy and shock wave lithotripsy in the management of ureteral calculi in eastern China

INTRODUCTION

It was the aim of this study to compare the efficiency and safety between shock wave lithotripsy (SWL) and ureteroscopic holmium laser lithotripsy (URL) methods for ureteral calculi while also determining which option is more cost-effective.

PATIENTS AND METHODS

During January 2008 to September 2009, a prospective randomized study was conducted to compare both modalities for the management of solitary radiopaque ureteral stones. Patient and stone characteristics, treatment outcome and charges were documented. Both options were compared using univariate statistical tests to identify the efficiency quotient and cost-effectiveness for ureteral calculi according to the stone location.

RESULTS

A total of 257 patients were in the SWL group, while 269 were in the URL group. The efficiency quotients for SWL and URL were 0.81 and 0.88, respectively. The initial stone-free rate of URL for lower ureteral calculi was higher (p = 0.002), while the complication rate of SWL for upper ureteral calculi was lower (p = 0.027). The SWL group required lower hospitalization charges (USD 440 vs. 1,221; p < 0.001), lower total charges (USD 454 vs. 1,284; p < 0.001) and a shorter period of hospitalization (5.4 vs. 6.6 days; p < 0.001) compared with the URL group for all ureteral locations. For mid and lower ureteral calculi, the postoperative office visits of the URL group were fewer (1.03 vs. 1.1 times; p = 0.001).

CONCLUSIONS

Primary in situ SWL for upper and middle ureteral calculi showed lower complication rates compared to URL and was more cost-effective in Eastern China. However, primary URL was a better option for treating lower ureteral stones with a higher stone-free rate but was more expensive.

Tubeless procedure is most important factor in reducing length of hospitalization after percutaneous nephrolithotomy: results of univariable and multivariable models

OBJECTIVES

To evaluate the effects of kidney stones and patient-related parameters on the length of hospitalization (LOH), which is one important factor affecting the cost effectiveness of percutaneous nephrolithotomy (PCNL). Recently, increases in healthcare costs have highlighted the importance of evaluating the cost effectiveness of a treatment as much as its efficacy.

MATERIAL AND METHOD

During an 8-year period, the records of 1669 patients with renal calculi who underwent PCNL were reviewed retrospectively. Eleven patients with urosepsis were excluded from the present study. A total of 1658 patients were categorized into 2 groups (group 1 = ≤2 days; group 2 = >2 days) according to the median LOH (median = 2 days). Multivariate binary logistic regression analysis was used to detect the effects of independent variables, including the patient age, gender, body mass index, history of extracorporeal shock wave lithotripsy or open surgery, stone size and opacity, presence of hydronephrosis, and localization and number of accesses, on the LOH after PNL.

RESULTS

Overall success was achieved in 86.2% of cases after one session of PCNL. The mean length of hospitalization was 2.89 ± 1.66 days (range, 1-21). According to the outcome of the multivariate analysis, diabetes (P = .0001, OR = 1.67), impaired kidney function (P = .03, OR = 1.64), stone size (P = .031, OR = 1.31), number of accesses (P = .001, OR = 1.59), intercostal access (P = .001, OR = 1.79), and tubeless procedure (P = .0001, OR = 0.23) were variables influencing LOH.

CONCLUSIONS

The presence of diabetes, a large stone burden, intercostals access, multiple accesses, and impaired kidney function prolong the LOH after PCNL. The use of the tubeless procedure was able to diminish the LOH.

Improved cost-effectiveness and efficiency with a slower shockwave delivery rate

OBJECTIVE

To determine the benefits of a slower shockwave (SW) delivery rate of 70 shocks/min on the treatment efficiency and cost-effectiveness of extracorporeal SW lithotripsy (ESWL).

PATIENTS AND METHODS

Patients who had ESWL for their upper urinary tract radio-opaque calculi were categorized into two groups: slow (70 SW/min) and fast (100 SW/min) delivery rate. All treatment was carried out using a lithotripter (Model S, Dornier MedTech, Wessling, Germany) as an outpatient procedure with no anaesthesia or sedation. The groups were followed for > or =6 months. The primary outcomes compared were the stone-free rate, re-treatment rate, additional procedure rate, perceived cost and actual cost. Clinical success was defined as stone-free status or asymptomatic insignificant residual fragments of <3 mm. Perceived cost was defined as the cost of ESWL alone, and actual cost included the cost of additional procedures and overhead costs to result in clinical success.

RESULTS

In all, the study included 102 patients, categorized into the fast (51) and slow (51) rate groups. The groups were comparable in terms of sex, age, body mass index, stone size and stone location. The slow group had a significantly better stone-free rate (67% vs 25.5%, P = 0.002, chi-square), fewer mean shocks to clinical success (3045 vs 4414, P < 0.001, U-test), lower re-treatment rate (22% vs 45%P = 0.013, chi -square), a lower additional procedure rate (12% vs 29%, P = 0.02, chi-square), greater efficiency quotient (0.51 vs 0.16) than the fast group. The mean perceived cost of ESWL (GB pound 297 vs 394 pounds, P = 0.013, U-test) and the mean actual cost of the slow group were significantly less (496 pounds vs 1002 pounds, P = 0.001, U-test).

CONCLUSION

Slowing the SW delivery rate to 70/min significantly reduced the actual cost by half and improved treatment efficiency.

Comparison of two different running models for the shock wave lithotripsy machine in Taipei City Hospital: self-support versus outsourcing cooperation

To compare two different running models including self-support and outsourcing cooperation for the extracorporeal shock wave lithotripsy (SWL) machine in Taipei City Hospital, we made a retrospective study. Self-support means that the hospital has to buy an SWL machine and get all the payment from SWL. In outsourcing cooperation, the cooperative company provides an SWL machine and shares the payment with the hospital. Between January 2002 and December 2006, we used self-support for the SWL machine, and from January 2007 to December 2008, we used outsourcing cooperation. We used the method of full costing to calculate the cost of SWL, and the break-even point was the lowest number of treatment sessions of SWL to make balance of payments every month. Quality parameters including stone-free rate, retreatment rate, additional procedures and complication rate were evaluated. When outsourcing cooperation was used, there were significantly more treatment sessions of SWL every month than when utilizing self-support (36.3 +/- 5.1 vs. 48.1 +/- 8.4, P = 0.03). The cost of SWL for every treatment session was significantly higher using self-support than with outsourcing cooperation (25027.5 +/- 1789.8 NT$ vs. 21367.4 +/- 201.0 NT$). The break-even point was 28.3 (treatment sessions) for self-support, and 28.4 for outsourcing cooperation, when the hospital got 40% of the payment, which would decrease if the percentage increased. No significant differences were noticed for stone-free rate, retreatment rate, additional procedures and complication rate of SWL between the two running models. Besides, outsourcing cooperation had lower cost (every treatment session), but a greater number of treatment sessions of SWL every month than self-support.

Evaluation of urothelial stretch-induced cyclooxygenase-2 expression in a mouse ureteral obstruction model

Prostanoids play a major role in the nociceptive response to ureteral obstruction. Cyclooxygenases (COXs) 1 and 2 catalyze the rate-limiting step in prostanoid synthesis; COX-2 is the more inducible isoform. Previous studies in human and animal models have shown that COX-2 is highly induced during ureteral obstruction. Our objective was to characterize acute COX-2 induction in a reproducible mouse model. Unilateral ureteral ligation was performed, and obstruction was maintained for 2, 4, 6, 8, or 12 hours. We evaluated COX-2 protein expression using Western immunoblotting, and found that ureteral obstruction induced COX-2 expression ninefold within 6 hours. This is the first report to characterize in vivo temporal stretch-induced COX-2 expression in a mouse model. This model will be critical for elucidation of COX-2 signaling pathways and may eventually help to identify novel therapeutic targets for treating ureteral obstruction.

Medical therapy of stone disease: from prevention to promotion of passage options

Medical therapy has been used for many years in the prevention of urinary stones. Medications directed at correcting urinary metabolic abnormalities responsible for promoting stone formation include thiazide diuretics, citrate salts, and allopurinol. All have proven to be efficacious. In addition, intake of citrate-rich juices, such as lemonade, may help to reduce urinary stone formation. More recently, there has been increasing interest in and use of medical therapy to aide in the passage of ureteral stones. Medical expulsive therapy (MET) has been shown to be cost effective compared with observation followed by treatment. Alpha-adrenergic receptor blockers are most commonly prescribed to promote passage of ureteral stones. They are able to facilitate stone passage, reduce time to passage, and decrease pain. Calcium-channel blockers also increase stone-passage rates. Steroids are useful adjuncts in MET.

Impact of body mass index on clinical and cost outcomes after radical cystectomy

OBJECTIVE

To evaluate the effect of body mass index (BMI, kg/m(2)) on the cost and clinical variables after radical cystectomy (RC), as studies show that obesity might adversely affect the outcomes after RC.

PATIENTS AND METHODS

The charts of patients who had RC from January 2004 to March 2007 were reviewed retrospectively. Complete cost and clinical information was available for 99 patients; the patient and tumour characteristics and peri-operative outcomes were recorded. Detailed cost information (room and board, laboratory, pharmacy, radiology, operating room, surgical supply, anaesthesia, and recovery room) was obtained from hospital billing. Patients were stratified and compared in three groups of BMI, i.e. normal weight (<25), overweight (25-<30) and obese (> or =30).

RESULTS

The mean age of the patients was 66 years; 27% were normal weight, 38% were overweight and 34% were obese. Of obese patients, 24% had an Eastern Cooperative Oncology Group performance score of 0, vs none and 2.6% in the normal and overweight groups, respectively (P = 0.001). Those of normal weight had the highest overall and major complication rates (P = 0.57 and 0.28, respectively). Obese patients had insignificantly higher transfusion rates (P = 0.28). The direct cost was higher in normal weight ($14,314) than overweight ($13,808) and obese ($13,666) patients (P = 0.47). Higher room and board cost in normal-weight patients was the only significant cost difference (P = 0.008).

CONCLUSION

BMI was not associated with increased costs of cystectomy. The absence of differences in cost-related and clinical outcomes might be attributable to variable comorbidity among groups and the experience of a high-volume surgeon and staff at a tertiary-care referral centre that routinely cares for obese patients.

Eighteen-year experience with the Medstone STS lithotripter: safety, efficacy, and evolving practice patterns

OBJECTIVE

To evaluate trends in safety, efficacy, and practice patterns for shockwave lithotripsy (SWL) procedures performed during a 18-year period and correlate the findings with recent evidence-based practice guidelines.

MATERIALS AND METHODS

From January 1988 to June 2006, 66,819 SWLs were performed using the Medstone STS lithotripter in patients with radiologic evidence of stones in the kidney or ureter. Treatment characteristics, such as stone location and size, need of re-treatment, and final success rate were recorded. The procedures were further divided by year for statistical consideration. Statistical analysis was performed using Student t test; P < 0.05 was considered significant.

RESULTS

Overall SWL success rate was 85% (39,667/46,669), and the overall re-treatment rate was 7.2% (3,417/46,669). There was no significant change in the overall proportion of lower-pole calculi managed with SWL, although there was a significant decrease in the proportion of SWL used for lower calix stones larger than 16 mm in the time period after 2000 (P = 0.006). There was a steady increase in the number of procedures performed for renal calculi in other locations per year, in particular for intrarenal calculi smaller than 20 mm. Intrarenal stones larger than 30 mm decreased as a proportion of procedures per year (P = 0.048) There was no significant change in the proportion of upper and distal ureteral stones managed, corresponding to a solid plateau in the percentage of SWL performed per year.

CONCLUSION

Our study did not demonstrate an overall drop in SWL; however, it did show the interference of endoscopic procedures on two case scenarios. There was a significant decrease (P = 0.048) in SWL for renal stones larger than 30 mm, and the same trend was noted for lower calix stones larger than 15 mm (P = 0.06).

Effects of shock waves on tenocyte proliferation and extracellular matrix metabolism

The shock wave is an effective noninvasive modality for resolving various tendon pathologies. However, scientific rationale and mechanism of shock wave therapy remains limited. This study aims to investigate the effects of shock waves and their biochemical mechanisms on tenocyte proliferation and collagen synthesis. Tenocytes harvested from Achilles tendons of Sprague-Dawley rats were used in this study. Cell viability was assayed by trypan blue exclusion methods. The colorimetric assay was determined to evaluate the mitochondria activity of the tenocytes after shock wave exposure. Synthesis of collagen, nitric oxide (NO) and transforming growth factor-beta1 (TGF-beta1) were determined and their gene expression was also studied. The results showed that there was a dose-dependent impairment of cell viability observed in 0.36 mJ/mm2 and 0.68 mJ/mm2 stimulation. In the proliferation assay, low energy level with low impulses (0.36 mJ/mm2 with 50 and 100 impulses) showed positive stimulatory effects, whereas the high energy level with high impulses (0.68 mJ/mm2 with 250 and 500 impulses) had significant inhibitory effects. At 0.36 mJ/mm2, 100 impulse shock waves treatment, up-regulation of proliferating cell nuclear antigen (PCNA) (at 6 and 24 h) and collagen type I, collagen type III and TGF-beta1 gene expression (at 24 h) were observed; these were followed by the increases in NO production (at 24 h), TGF-beta1 release (at 48 and 96 h) and collagen synthesis (at the 7th day). This study revealed that shock waves can stimulate tenocyte proliferation and collagen synthesis. The associated tenocyte proliferation is mediated by early up-regulation of PCNA and TGF-beta1 gene expression, endogenous NO release and synthesis and TGF-beta1 protein and then collagen synthesis.

Determinants of quality of life for patients with kidney stones

PURPOSE

We evaluated various factors relating to quality of life in a population of patients with stones.

MATERIALS AND METHODS

A total of 155 patients seen at our urology clinic for stones between January and May 2007 were prospectively questioned regarding stone history and were administered the SF-36 questionnaire to assess quality of life. Age, body mass index, American Society of Anesthesiologists score, number of stone episodes, interval from the last stone episode, number of surgical procedures for stones and associated complications, missed days of work and long-term medical treatment were elicited from the patients. Individual SF-36 domains and composite scores were compared to those of the American general population. Univariate and multivariate regression analyses were performed to assess the impact of all covariates on quality of life scores.

RESULTS

Patients with stones scored lower than the average American population in 5 of the 8 domains of the SF-36 as well as in the physical composite score. Multivariate regression modeling showed that increasing body mass index and age were the strongest predictors of decreased physical well-being. The number of stone episodes did not influence SF-36 scores, although the number of surgical procedures impacted physical and mental components. The number of ureteroscopy procedures and stent placements primarily impacted mental well-being. Medical therapy, particularly the use of potassium citrate, was associated with more favorable quality of life.

CONCLUSIONS

Various factors impact quality of life in patients with urolithiasis but the most important are body mass index, age and the number of surgical procedures. Prospective longitudinal studies may further elucidate the determinants of quality of life and they might be used to optimize patient care.