Abstract
Purpose:
To assess variation in surveillance imaging practices in various clinical contexts among patients with urinary stone disease (USD) from a large cohort of U.S. Veterans.
Materials and Methods:
We identified adults age ≥ 18 years within the Veterans Health Administration Corporate Data Warehouse with an index surgical procedure related to USD or an index emergency department (ED) visit with a primary diagnosis of USD between 2010 and 2018. We then explored three clinical periods for use of surveillance imaging: 30–180 days and 180–540 days post-surgery and 90–540 days post-ED visit. We estimated multilevel logistic regression models to identify factors associated with receipt of surveillance imaging. We calculated median odds ratios (MORs) to quantify the amount of variation in imaging procedures by facility.
Results:
Among 35,248 patients who met inclusion criteria, 10,095 underwent a surgical procedure, and 25,153 had an ED visit. Probabilities of obtaining post-operative imaging 30–180 days post-surgery by facility ranged from 8.4% to 58.5%; from 6.8% to 35.4% for 180–540 days post-surgery; and from 6.1% to 20.5% for 90–540 days post-ED. The greatest between-facility variation occurred 30–180 days post-surgery (MOR: 1.81 [95% confidence interval, 1.66 to 2.04). There was also wide variation in the type of post-surgical imaging. Combination imaging, x-ray, and ultrasound were the most common imaging modalities obtained in the 30–180 day period for percutaneous nephrolithotomy, shockwave lithotripsy, and ureteroscopy, respectively.
Conclusions:
Among patients with USD, the use of surveillance imaging after surgery and in the post-ED visit setting remains low, with substantial variation across facilities.
Keywords: Practice patterns, Nephrolithiasis, Imaging, urological surgical procedures
Introduction
Urinary stone disease (USD) is a prevalent condition that affects about 1 in 10 Americans in their lifetime.1 Kidney stone prevalence has increased from 5.2% in 1994 2 to 10.1% in 2016,3 and approximately 50% of stone formers will experience another kidney stone event within 10 years.4 Due to the recurrent nature of kidney stone events, clinical guidelines recommend follow-up imaging to monitor stone activity and to tailor diet and medical therapy.
However, due to lack of evidence supporting imaging use, there is limited guidance beyond the recommendation for periodic interval imaging.5 For example, the 2016 American Urological Association (AUA) Guidelines on Surgical Management of Stones did not comment on how often or what imaging modality should be obtained post-intervention to determine stone clearance.6 Similarly, the 2012 AUA Technology Assessment for Ureteral Stones stated that follow-up imaging should be obtained to document stone clearance and resolution of any preoperative hydronephrosis, but it did not comment on when follow-up studies should be obtained.7 Given the lack of specificity in society guidelines regarding follow-up imaging for USD, we hypothesized there is wide variation in imaging practices across various clinical contexts.
Therefore, our objective was to assess facility level variation in surveillance imaging practices using data from the Veterans Health Administration (VHA) in three clinical contexts where diagnostic imaging would be expected to have the most utility: post-surgery (early: 30–180 days and longer-term: 180–540 days surveillance) and post-Emergency Department (ED) visit: 90–540 days. Since diagnostic imaging is the most sensitive way to detect interval stone growth and new stone development, current imaging practices must be described before an optimal frequency for imaging surveillance can be determined.
Materials and Methods
Data Source and index USD Cohort Selection
We analyzed data from the Veterans Health Administration (VHA) Corporate Data Warehouse, which is composed of inpatient and outpatient records from 23.5 million living and deceased U.S. veterans that regularly obtain care from the VHA. First, we identified adults within the VHA age ≥ 18 years with an index surgical encounter related to USD or ED visits with a primary diagnosis of USD between 2010 and 2018. We excluded patients with imaging in 2020 to prevent any impact of the COVID-19 pandemic on follow-up imaging rates. The relevant surgical/imaging procedure, CPT codes, and ICD-9/10 diagnosis codes are listed in the Appendix.
Patients had no USD-related claims for 1 year prior to the index encounter to restrict our cohort to patients with a recent, incident stone event. We also excluded those who had recurrent stone events (inpatient admission or ED-visit with a primary diagnosis of USD or surgery for USD) during the follow-up periods, since individuals with stone events likely received ad hoc imaging and we wanted to focus on surveillance imaging practices. Patients undergoing surgery 30 days before or 90 days after an ED visit were also excluded to eliminate imaging obtained due to surgical complications. See Supplementary Figure S3 for a flow chart of inclusion criteria.
Clinical Context Selection
We explored three clinical contexts: 30–180 days and 180–540 days post-USD surgery and 90–540 days post-ED visit. We chose these specific post-operative periods to coincide with common post-operative imaging assessment periods.7,8 We chose to start the post-operative period of 30–180 days at day 30 to exclude early imaging obtained related to surgical complications. We chose 180–540 days as the longer-term post-operative surveillance period to capture imaging that urologists would be ordering to evaluate for new stone activity, which is usually obtained 12 months after the initial post-operative imaging.9 We chose a 90–540 day post-ED visit period as we expected any imaging related to the acute stone event/passage would have resolved by 3-months and that clinicians would obtain longer term follow-up imaging to evaluate for new stone activity.5 Surgical patients were excluded from this sub-cohort. Imaging modalities queried for included: renal ultrasound (US), abdominal x-ray (x-ray), computed tomography (CT), and combination imaging (any combination of the three imaging modalities e.g. x-ray and US or US and CT, etc. – See Appendix).
Statistical Analysis
We performed descriptive statistics for patients undergoing any imaging for each clinical period by age, sex, race, ethnicity, high risk status, geographic region (Northeast, South, Midwest, West), and index surgical procedure type (percutaneous nephrolithotomy (PCNL), shockwave lithotripsy (SWL), ureteroscopy (URS); Table 1). High-risk patients were defined as those with at least 1 concomitant comorbid condition associated with USD within 12 months of the index USD encounter, using a previously published approach (see Appendix).10 Imaging utilization was determined by calculating the percentage of patients meeting inclusion criteria imaged at each facility over the study period. Patients undergoing multiple imaging studies were not considered twice. Facilities were then stratified in the top or bottom 50% of imaging utilization for Table 1 to identify distinguishing characteristics between facilities with high and low imaging utilization.
Table 1.
Descriptive results of patient demographics with incident urinary stone disease by clinical context and stratified by VHA facility imaging utilization.
| Variables | Surgery 30 – 180 Days | Surgery 180 – 540 Days | Surgery Overall | ED 90 – 540 Days | ED Overall | |||
|---|---|---|---|---|---|---|---|---|
|
| ||||||||
| Bottom Half (N=5296) | Top Half (N=4799) | Bottom Half (N=4773) | Top Half (N=5322) | Total (N=10095) | Bottom Half (N=10219) | Top Half (N=14934) | Total (N=25153) | |
| Age | ||||||||
| Mean (SD) | 61.8 (13.8) | 61.8 (13.3) | 61.8 (13.7) | 61.8 (13.3) | 61.8 (13.5) | 56.1 (14.7) | 55.7 (14.7) | 55.9 (14.7) |
| Gender | ||||||||
| Female | 297 (5.6%) | 312 (6.5%) | 281 (5.9%) | 328 (6.2%) | 609 (6.0%) | 685 (6.7%) | 1029 (6.9%) | 1714 (6.8%) |
| Male | 4999 (94.4%) | 4487 (93.5%) | 4492 (94.1%) | 4994 (93.8%) | 9486 (94.0%) | 9534 (93.3%) | 13905 (93.1%) | 23439 (93.2%) |
| Race | ||||||||
| Missing (n=) | 282 | 302 | 267 | 317 | 584 | 529 | 975 | 1504 |
| American Indian/Native American | 37 (0.7%) | 37 (0.8%) | 31 (0.7%) | 43 (0.9%) | 74 (0.8%) | 104 (1.1%) | 124 (0.9%) | 228 (1.0%) |
| Asian | 31 (0.6%) | 27 (0.6%) | 25 (0.6%) | 33 (0.7%) | 58 (0.6%) | 95 (1.0%) | 159 (1.1%) | 254 (1.1%) |
| Black | 586 (11.7%) | 475 (10.6%) | 557 (12.4%) | 504 (10.1%) | 1061 (11.2%) | 1251 (12.9%) | 1563 (11.2%) | 2814 (11.9%) |
| Native Hawaiian or Pacific Islander | 43 (0.9%) | 36 (0.8%) | 33 (0.7%) | 46 (0.9%) | 79 (0.8%) | 72 (0.7%) | 147 (1.1%) | 219 (0.9%) |
| White | 4317 (86.1%) | 3922 (87.2%) | 3860 (85.7%) | 4379 (87.5%) | 8239 (86.6%) | 8168 (84.3%) | 11966 (85.7%) | 20134 (85.1%) |
| Ethnicity | ||||||||
| Missing (n=) | 182 | 161 | 167 | 176 | 343 | 301 | 522 | 823 |
| Hispanic/Latino | 208 (4.1%) | 253 (5.5%) | 207 (4.5%) | 254 (4.9%) | 461 (4.7%) | 521 (5.3%) | 1332 (9.2%) | 1853 (7.6%) |
| Non-Hispanic/Latino | 4906 (95.9%) | 4385 (94.5%) | 4399 (95.5%) | 4892 (95.1%) | 9291 (95.3%) | 9397 (94.7%) | 13080 (90.8%) | 22477 (92.4%) |
| High-Risk Status | ||||||||
| High Risk | 1578 (29.8%) | 1441 (30.0%) | 1433 (30.0%) | 1586 (29.8%) | 3019 (29.9%) | 2119 (20.7%) | 3040 (20.4%) | 5159 (20.5%) |
| Not High Risk | 3718 (70.2%) | 3358 (70.0%) | 3340 (70.0%) | 3736 (70.2%) | 7076 (70.1%) | 8100 (79.3%) | 11894 (79.6%) | 19994 (79.5%) |
| Region | ||||||||
| Midwest | 1666 (31.5%) | 803 (16.7%) | 1542 (32.3%) | 927 (17.4%) | 2469 (24.5%) | 2177 (21.3%) | 2595 (17.4%) | 4772 (19.0%) |
| Northeast | 718 (13.6%) | 363 (7.6%) | 565 (11.8%) | 516 (9.7%) | 1081 (10.7%) | 1160 (11.4%) | 1373 (9.2%) | 2533 (10.1%) |
| South | 1791 (33.8%) | 2664 (55.5%) | 1690 (35.4%) | 2765 (52.0%) | 4455 (44.1%) | 4122 (40.3%) | 7425 (49.7%) | 11547 (45.9%) |
| West | 1121 (21.2%) | 969 (20.2%) | 976 (20.4%) | 1114 (20.9%) | 2090 (20.7%) | 2760 (27.0%) | 3541 (23.7%) | 6301 (25.1%) |
| Surgery Type | ||||||||
| Percutaneous nephrolithotomy | 128 (2.4%) | 116 (2.4%) | 119 (2.5%) | 125 (2.3%) | 244 (2.4%) | |||
| Shockwave lithotripsy | 398 (7.5%) | 392 (8.2%) | 400 (8.4%) | 390 (7.3%) | 790 (7.8%) | |||
| Ureteroscopy | 4770 (90.1%) | 4291 (89.4%) | 4254 (89.1%) | 4807 (90.3%) | 9061 (89.8%) | |||
We then fit three separate multilevel random-intercepts models to examine factors associated with imaging. Specifically, we estimated two-level logistic regression models with random-effects terms for each VHA facility, evaluating receipt of imaging at each period. To ensure sufficient samples sizes for our models, we included procedure types in the models and controlled for them without stratifying by follow-up period. We excluded VHA facilities with fewer than 5 USD patients and those with fewer than 5 follow-up imaging studies since these practices may not be representative of urologists who commonly manage USD. A total of 12 facilities with < 5 post-surgical imaging tests (n=25) and 16 facilities with < 5 post-ED visit imaging tests (n=35) were excluded. For each VHA facility, model-adjusted predicted probabilities of follow-up imaging by clinical context, along with 95% confidence intervals (CIs), were calculated and plotted in rank order. From these multilevel models, we calculated median odds ratios (MORs) and corresponding 95% CIs to quantify the amount of variation for receipt of imaging attributed to the individual VHA facility (Table 2). MORs are defined as the median difference in odds of imaging being obtained when comparing two randomly selected facilities.11 We controlled for patient age, sex, race, ethnicity, high risk status, geographic region, and surgery type in these analyses.
Table 2.
Results of multi-level logistic regression models demonstrating imaging rates by clinical context.
| Variable | Post-operative imaging 30 – 180 days | Longer-term Post-operative imaging 180 – 540 days | Post-ED Imaging 90 – 540 days | |||
|---|---|---|---|---|---|---|
|
| ||||||
| OR | 95% CI | OR | 95% CI | OR | 95% CI | |
| Between-facility Median Odds Ratio (MOR) | 1.81 | (1.66, 2.04) | 1.50 | (1.39, 1.60) | 1.28 | (1.22, 1.33) |
| Surgery Type (Reference: Shockwave Lithotripsy) | ||||||
| Percutaneous Nephrolithotomy | 0.67 | (0.48, 0.93) | 1.41 | (1.02, 1.94) | ||
| Ureteroscopy | 0.68 | (0.57, 0.81) | 0.99 | (0.83, 1.18) | ||
| Age, Scale by Decades | 1.14 | (1.1, 1.19) | 1.15 | (1.11, 1.19) | 1.20 | (1.18, 1.23) |
| Gender (Reference: Female) | ||||||
| Male | 0.80 | (0.66, 0.97) | 0.96 | (0.79, 1.17) | 0.89 | (0.79, 1.00) |
| Race (Reference: White) | ||||||
| American Indian or Alaska Native | 0.66 | (0.39, 1.13) | 0.87 | (0.51, 1.46) | 0.78 | (0.57, 1.08) |
| Asian | 1.44 | (0.83, 2.5) | 0.80 | (0.44, 1.47) | 1.06 | (0.79, 1.42) |
| Black | 0.99 | (0.85, 1.15) | 1.14 | (0.98, 1.32) | 1.11 | (1.01, 1.21) |
| Native Hawaiian or Other Pacific Islander | 1.01 | (0.62, 1.66) | 1.16 | (0.72, 1.88) | 1.17 | (0.87, 1.58) |
| Ethnicity: Hispanic or Latino (Ref: Not Hispanic or Latino) | 0.98 | (0.77, 1.24) | 1.03 | (0.81, 1.31) | 1.04 | (0.91, 1.18) |
| High Risk (Reference: Not High Risk) | 1.09 | (0.98, 1.2) | 1.23 | (1.11, 1.35) | 1.35 | (1.26, 1.45) |
| Incident Event Year (Reference: 2010) | ||||||
| 2011 | 0.90 | (0.73, 1.1) | 0.99 | (0.81, 1.21) | 1.03 | (0.91, 1.16) |
| 2012 | 0.89 | (0.73, 1.08) | 0.88 | (0.73, 1.08) | 1.02 | (0.91, 1.16) |
| 2013 | 0.92 | (0.76, 1.13) | 0.91 | (0.75, 1.11) | 1.03 | (0.91, 1.17) |
| 2014 | 0.97 | (0.80, 1.18) | 0.84 | (0.69, 1.02) | 1.08 | (0.95, 1.22) |
| 2015 | 1.23 | (1.02, 1.49) | 1.00 | (0.83, 1.21) | 1.07 | (0.95, 1.21) |
| 2016 | 1.23 | (1.02, 1.49) | 0.92 | (0.76, 1.11) | 1.01 | (0.89, 1.14) |
| 2017 | 1.46 | (1.21, 1.77) | 1.11 | (0.92, 1.34) | 1.02 | (0.90, 1.15) |
| 2018 | 1.74 | (1.39, 2.18) | 0.95 | (0.75, 1.19) | 0.99 | (0.86, 1.12) |
| Region | ||||||
| Northeast (Reference: Midwest) | 0.90 | (0.58, 1.39) | 0.84 | (0.6, 1.17) | 1.00 | (0.81, 1.23) |
| South | 1.33 | (0.94, 1.88) | 0.95 | (0.73, 1.23) | 1.12 | (0.95, 1.32) |
| West | 1.08 | (0.73, 1.61) | 0.78 | (0.58, 1.05) | 1.02 | (0.85, 1.23) |
We conducted all analyses using R version 4.0.5. We performed 2-sided significance testing with alpha set at 0.05. The study was approved by the Institutional Review Board of the Veterans Administration (VA) Ann Arbor Healthcare System with a waiver of informed consent.
Results
Among 35,248 patients with an index encounter for USD in our study, 10,095 underwent a surgical procedure for USD and 25,153 (67%) had an ED-visit for USD (Table 1). Table 1 shows patient characteristics of those at high and low imaging facilities. Figure 1 shows post-operative imaging practices by USD surgery. The most common imaging modalities obtained 30–180 days and 180–540 days post-PCNL were combination imaging and CT at 34.4% and 31.1%, respectively. X-ray was the most common imaging study after SWL for the 30–180 day and 180–540 day postoperative periods at 59.6% and 48.2%, respectively. After URS, US was the most common imaging type for the 30–180 day period and x-ray was the most common imaging for the 180–540 day period at 43.3% and 30.3%, respectively (Figure 1). Rates of CT scan obtained 30–180 days after PCNL, SWL, and URS were 21.2%, 6.1%, and 13.7%, respectively. Rates of CT scan obtained 180–540 days after PCNL, SWL, and URS were 31.1%, 18.1%, and 20.9%. CT was the most common imaging obtained post-ED visit at 29.2% (Figure 1).
Figure 1.
Stacked bar graph chart demonstrating imaging practices by clinical context for incident urinary stone disease
The caterpillar plots show the model-adjusted predicted probability of follow-up imaging for each VHA facility. In Figure 2A, the median follow-up imaging rate for the 30–180 day period was 23.8% with a range of 8.4% to 58.5%. In Figure 2B, the median follow-up imaging rate for the 180–540 day period was 17.7% with a range of 6.8% to 35.4%. In Figure 2C, the median follow-up imaging rate post-ED visit was 11.2% with a range of 6.1% to 20.5%.
Figure 2A.
Adjusted Caterpillar plots demonstrating imaging variation across VHA facilities post-surgery 30 – 180 Days
21.9% fully above, 14.9% fully below the median
Figure 2B.
Adjusted Caterpillar plots demonstrating imaging variation across VHA facilities post-surgery 180 – 540d
14.0% fully above, 6.1% fully below the median
Figure 2C.
Adjusted Caterpillar plots demonstrating imaging variation across VHA facilities post-ED visit 90–540d
10.6% fully above, 10.6% fully below the median.
Supplementary Fig. S1 shows time trends of imaging 30–180 days post-URS between 2010–2018. In the post-URS setting, overall imaging rates increased from 31% of patients in 2012 to 49% by 2018. There was an increase in ultrasound use beginning in 2012 to 2018, from 15.8% to 35.8%, respectively. Supplementary Fig. S2 shows time trends for 90–540 days post-ED visit imaging. The overall use of post-ED imaging remained stable, due to a decrease in x-ray and concurrent increase in US over the study period, which began around 2011. Other time trends for imaging modalities (e.g. SWL 30–180 days and 180–540 days, PCNL 30–180 days and 180–540 days) had abnormal variation or were too flat to be considered for additional comment so time trend graphs for these are not included.
The multilevel logistic regression model identified a between-facility MOR of 1.81 (95% CI: 1.66–2.04) for receiving imaging 30–180 days post-surgery (Table 2). The MOR for the 180–540 day period was 1.50 (95% CI: 1.39–1.60), and the MOR for imaging 90–540 days post-ED visit was 1.28 (95% CI: 1.22–1.33, Table 2). High-risk patients also had increased odds of imaging 180–540 days post-surgery (OR: 1.23; 95% CI: 1.11–1.35) and post-ED visit (OR: 1.35; 95% CI: 1.26–1.45), but not for 30–180 days post-surgery (p>0.05).
Discussion
We identified wide variation across VHA facilities for obtaining diagnostic imaging for surveillance of USD in various clinical contexts. Imaging rates increased over the study period in the post-URS setting, driven by increasing utilization of US. The greatest variation was observed in the 30–180 day period with a MOR of 1.81; meaning that when comparing two randomly selected facilities, the median difference in odds of a patient receiving post-operative imaging is 81%. A MOR of 1.50 was identified for imaging in the 180–540 days post-operative setting. The least imaging variation was seen for 90–540 days post-ED visit with a MOR of 1.28. Rates of CT scan were generally low in the 30–180 day and 180–540 day post-operative periods.
Our findings of low imaging rates with wide variation in the post-operative setting is consistent with prior literature. An analysis of Marketscan data between 2007–2014 identified that many commercially insured patients did not undergo any follow-up imaging within one year of URS. At 12 months, 39% of patients had not received imaging after URS.12 For the post-ED visit 90–540 day surveillance period, we noted a low median follow-up imaging rate of 11.2% and a MOR of 1.28. This low imaging rate is similar with a prior analysis of Marketscan that showed only 48.3% of patients received follow-up care after an ED visit for USD.13
We posit that the lack of available evidence and specificity in the AUA and European Association of Urology (EAU) guidelines 5,6 has contributed towards greater variation in the use of post-operative imaging. Generally, the guidelines do not provide specific detail on when imaging should be obtained and with what modality.6 Contrary to our study findings, we had initially expected the 30–180 day period would have the least variation as we thought evaluating for residual fragments and hydronephrosis in the short term after surgery was common practice. Yet, a survey-based study of 322 North-American urologists showed that 52% did not order routine post-operative imaging.14 With the new 2025 AUA stone guidelines recommending postoperative follow-up imaging (suggested 4–12 weeks), imaging rates may increase.15 Our finding of increasing use of US after URS since 2012 is similar to what others have reported,12,16,17 and may coincide with the AUA Technology Assessment published around that time, which recommended a combination of x-ray and US for follow-up of a radiopaque ureteral stone.7 For longer-term surveillance imaging, the AUA guidelines recommended a 1-year surveillance interval for stable USD patients;5 while the EAU guidelines recommend that stone-free, post-operative patients should be imaged at 6 and 12 months for up to 3 years with more intensive imaging for high-risk patients.9,18 Consistent with EAU recommendations, in our study, we show that patients at higher risk of stone recurrence had an association with receiving imaging in the 180–540 day post-surgery period.
Our study has several limitations. We analyzed the VHA Data Warehouse, which is predominantly male and older (Table 1), therefore, our results may not be generalizable to female or younger populations. However, our models did adjust for sex and age. Furthermore, other studies examining non-VHA populations found similar rates of low imaging, suggesting our results are generalizable. Second, we used CPT/ICD codes to identify the study cohort and use of imaging tests. Thus, there is a potential for miscoding and we lack information on stone size, symptoms, whether imaging was planned/unplanned, and whether there were residual stones after surgery. However, to mitigate these limitations, we chose to focus on patients with recent stone events by excluding those with any USD-related claims in the year prior to the index encounter and we excluded patients who had surgery around the time of ED visits. Finally, some imaging may have occurred outside of the VHA system, which would not be captured in our study. However, use of non-VHA hospitals by VHA patients is low.19 Furthermore, since our study focused on recent stone encounters within the VHA system, it is highly probable that patients received follow-up care through the VHA as well. The Veterans Choice Program, established in 2014 allows veterans to obtain care from non-VHA facilities only if wait times were > 30 days or the facility was > 40 miles away.20 Since our surgical cohort underwent surgery in the VHA, it is unlikely for the veteran to meet these criteria and obtain a referral. There is also a financial incentive to stay within the VHA since imaging at a non-VHA facility would require paying out of pocket.
Despite these limitations, our study confirms that wide variation exists for post-operative imaging surveillance. Since we identified low imaging rates in three different clinical scenarios, we suspect that patient factors may also be contributing to low imaging rates. It is important for clinicians to educate patients that even asymptomatic individuals can benefit from post-operative imaging to diagnose ureteral obstruction. Furthermore, clinicians should be aware of the 2012 AUA Technology Assessment recommendations that US should be performed routinely for patients with ureteral calculi given the severe consequences of potential renal loss with a missed diagnosis of silent obstruction.7 Lastly, our results show that CT is uncommonly performed after USD surgery. Although there is a current push by academic journals to standardize reporting of stone free rates using post-operative CT scans21, most urologists are not obtaining CT post-operatively.
Conclusions
Our study identified wide facility level variation in imaging practices in three different periods: post-operative, longer-term post-operative surveillance, and post-ED visit. There was wide imaging variation across facilities with adjusted median predicted probabilities for follow-up imaging ranging between 6.1% and 58.5%. X-ray, US, and combination imaging were the most performed imaging studies at 30–180 days after SWL, URS, and PCNL; respectively. Studies that help define optimal surveillance imaging protocols post-operatively and post-ED visits (i.e. correlating imaging with meaningful clinical outcomes such as stone recurrence, silent obstruction, long-term renal function) are needed before efforts to standardize imaging practices can be made.
Supplementary Material
Funding:
Research reported in this publication was supported by the National Institute of Diabetes and Digestive and Kidney Diseases of the National Institutes of Health under award number R01DK121709. The content is solely the responsibility of the authors and does not necessarily represent the official views of the National Institutes of Health. Matthew Lee is supported by the OSU College of Medicine Research Innovation and Career Development Award
Footnotes
Author Disclosures:
MSL: Consultant for Boston Scientific Corporation, Richard Wolf Medical Instruments. Data Monitoring Committee for Butterfly.
No disclosures for: KBS, AV, SP, JMH, VBS, RSH
References
- 1.Hill AJ, Basourakos SP, Lewicki P, et al. Incidence of Kidney Stones in the United States: The Continuous National Health and Nutrition Examination Survey. J Urol 2022;207(4):851–856. (In eng). DOI: 10.1097/ju.0000000000002331. [DOI] [PubMed] [Google Scholar]
- 2.Stamatelou KK, Francis ME, Jones CA, Nyberg LM, Curhan GC. Time trends in reported prevalence of kidney stones in the United States: 1976–1994. Kidney Int 2003;63(5):1817–23. (In eng). DOI: 10.1046/j.1523-1755.2003.00917.x. [DOI] [PubMed] [Google Scholar]
- 3.Chewcharat A, Curhan G. Trends in the prevalence of kidney stones in the United States from 2007 to 2016. Urolithiasis 2021;49(1):27–39. (In eng). DOI: 10.1007/s00240-020-01210-w. [DOI] [PubMed] [Google Scholar]
- 4.Scales CD Jr., Smith AC, Hanley JM, Saigal CS. Prevalence of kidney stones in the United States. Eur Urol 2012;62(1):160–5. (In eng). DOI: 10.1016/j.eururo.2012.03.052. [DOI] [PMC free article] [PubMed] [Google Scholar]
- 5.Pearle MS, Goldfarb DS, Assimos DG, et al. Medical management of kidney stones: AUA guideline. J Urol 2014;192(2):316–24. (In eng). DOI: 10.1016/j.juro.2014.05.006. [DOI] [PubMed] [Google Scholar]
- 6.Assimos D, Krambeck A, Miller NL, et al. Surgical Management of Stones: American Urological Association/Endourological Society Guideline, PART I. J Urol 2016;196(4):1153–60. (In eng). DOI: 10.1016/j.juro.2016.05.090. [DOI] [PubMed] [Google Scholar]
- 7.Fulgham PF, Assimos DG, Pearle MS, Preminger GM. Clinical effectiveness protocols for imaging in the management of ureteral calculous disease: AUA technology assessment. J Urol 2013;189(4):1203–13. (In eng). DOI: 10.1016/j.juro.2012.10.031. [DOI] [PubMed] [Google Scholar]
- 8.Weizer AZ, Auge BK, Silverstein AD, et al. Routine postoperative imaging is important after ureteroscopic stone manipulation. J Urol 2002;168(1):46–50. (In eng). [PubMed] [Google Scholar]
- 9.Skolarikos AJ H; Neisius A; Petřík A; Somani B; Tailly T; Gambaro G EAU Guidelines on Urolithiasis. EAU Guidelines. Arnhem, the Netherlands: EAU Guidelines Office; 2024. [Google Scholar]
- 10.Hsi RS, Yan PL, Goldfarb DS, et al. Comparison of Selective Versus Empiric Pharmacologic Preventative Therapy With Kidney Stone Recurrence. Urology 2021;149:81–88. (In eng). DOI: 10.1016/j.urology.2020.11.054. [DOI] [PMC free article] [PubMed] [Google Scholar]
- 11.Merlo J, Chaix B, Ohlsson H, et al. A brief conceptual tutorial of multilevel analysis in social epidemiology: using measures of clustering in multilevel logistic regression to investigate contextual phenomena. J Epidemiol Community Health 2006;60(4):290–7. (In eng). DOI: 10.1136/jech.2004.029454. [DOI] [PMC free article] [PubMed] [Google Scholar]
- 12.Ahn JS, Holt SK, May PC, Harper JD. National Imaging Trends after Ureteroscopic or Shock Wave Lithotripsy for Nephrolithiasis. J Urol 2018;199(2):500–507. (In eng). DOI: 10.1016/j.juro.2017.09.079. [DOI] [PubMed] [Google Scholar]
- 13.Luckenbaugh AN, Yan PL, Dauw CA, Ghani KR, Hollenbeck BK, Hollingsworth JM. Followup Care after Emergency Department Visits for Kidney Stones: A Missed Opportunity. Urol Pract 2019;6(1):24–28. (In eng). DOI: 10.1016/j.urpr.2018.01.001. [DOI] [PMC free article] [PubMed] [Google Scholar]
- 14.Omar M, Chaparala H, Monga M, Sivalingam S. Contemporary Imaging Practice Patterns Following Ureteroscopy for Stone Disease. J Endourol 2015;29(10):1122–5. (In eng). DOI: 10.1089/end.2015.0088. [DOI] [PubMed] [Google Scholar]
- 15.Pearle MS, Matlaga BR, Antonelli JA, et al. Surgical Management of Kidney and Ureteral Stones: AUA Guideline (2026) Part I: Evaluation and Treatment of Patients with Kidney and/or Ureteral Stones. J Urol 2025:101097ju0000000000004842. (In eng). DOI: 10.1097/ju.0000000000004842. [DOI] [PubMed] [Google Scholar]
- 16.Urologic Diseases in America. UDA Data Report: Epidemiology of non-malignant urologic disease in the United States. Bethesda, MD: National Institute of Diabetes and Digestive and Kidney Diseases, 2018. [Google Scholar]
- 17.Dai JC, Ahn JS, Holt SK, May PC, Sorensen MD, Harper JD. National Imaging Trends after Percutaneous Nephrolithotomy. J Urol 2018;200(1):147–153. (In eng). DOI: 10.1016/j.juro.2018.01.078. [DOI] [PubMed] [Google Scholar]
- 18.Tzelves L, Geraghty R, Lombardo R, et al. Duration of Follow-up and Timing of Discharge from Imaging Follow-up, in Adult Patients with Urolithiasis After Surgical or Medical Intervention: A Systematic Review and Meta-analysis from the European Association of Urology Guideline Panel on Urolithiasis. Eur Urol Focus 2023;9(1):188–198. (In eng). DOI: 10.1016/j.euf.2022.06.016. [DOI] [PubMed] [Google Scholar]
- 19.Vaughan Sarrazin M, Gao Y, Jacobs CA, et al. Private-Sector Readmissions for Inpatient Surgery in Veterans Health Administration Hospitals. JAMA Netw Open 2024;7(12):e2452056. (In eng). DOI: 10.1001/jamanetworkopen.2024.52056. [DOI] [PMC free article] [PubMed] [Google Scholar]
- 20.Office CB. The Veterans Community Care Program: Background and Early Effects. (https://www.cbo.gov/publication/57583#footnote-005 ).
- 21.Higgins AM, Ganesan V, Ghani KR, Agarwal DK, Borofsky MS, Dauw CA. The 2023 Stone-Free CT Mandate: Addressing the Two Sides of the Debate. J Endourol 2022;36(12):1522–1525. (In eng). DOI: 10.1089/end.2022.0610. [DOI] [PubMed] [Google Scholar]
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