The impact of kidney stone disease on quality of life in high-risk stone formers.

OBJECTIVE: To assess the impact of kidney stone disease (KSD) and its treatment on the health-related quality of life (HRQOL) of high-risk stone formers with hyperparathyroidism, renal tubular acidosis, malabsorptive disease, and medullary sponge kidney. PATIENTS AND METHODS: The Wisconsin Stone Quality of Life questionnaire was used to evaluate HRQOL in 3301 patients with a history of KSD from 16 institutions in North America between 2014 and 2020. Baseline characteristics and medical history were collected from patients, while active KSD was confirmed through radiological imaging. The high-risk group was compared to the remaining patients (control group) using the Wilcoxon rank-sum test. RESULTS: Of 1499 patients with active KSD included in the study, the high-risk group included 120 patients. The high-risk group had significantly lower HRQOL scores compared to the control group (P < 0.01). In the multivariable analyses, medullary sponge kidney disease and renal tubular acidosis were independent predictors of poorer HRQOL, while alkali therapy was an independent predictor of better HRQOL (all P < 0.01). CONCLUSIONS: Among patients with active KSD, high-risk stone formers had impaired HRQOL with medullary sponge kidney disease and renal tubular acidosis being independent predictors of poorer HRQOL. Clinicians should seek to identify these patients earlier as they would benefit from prompt treatment and prevention.

Risk of Symptomatic Kidney Stones During and After Pregnancy.

RATIONALE & OBJECTIVE: There are several well-known anatomical and physiological changes during pregnancy that could contribute to kidney stone formation, but evidence that they increase the risk of kidney stones during pregnancy is lacking. We determined whether there was an increased risk of a first-time symptomatic kidney stone during and after pregnancy. STUDY DESIGN: A population-based matched case-control study. SETTING & PARTICIPANTS: 945 female first-time symptomatic kidney stone formers aged 15-45 years and 1,890 age-matched female controls in Olmsted County, MN, from 1984-2012. The index date was the date of onset of a symptomatic kidney stone for both the case and her matched controls. EXPOSURE: The primary exposure was pregnancy with assessment for variation in risk across different time intervals before, during, and after pregnancy. Medical records were manually reviewed to determine the conception and delivery dates for pregnancies. OUTCOME: Medical record-validated first-time symptomatic kidney stone. ANALYTICAL APPROACH: Conditional and unconditional multivariable logistic regression analysis. RESULTS: Compared with nonpregnant women, the odds of a symptomatic kidney stone forming in women was similar in the first trimester (OR, 0.92; P=0.8), began to increase during the second trimester (OR, 2.00; P=0.007), further increased during the third trimester (OR, 2.69; P=0.001), peaked at 0 to 3 months after delivery (OR, 3.53; P<0.001), and returned to baseline by 1year after delivery. These associations persisted after adjustment for age and race or for diabetes mellitus, hypertension, and obesity. These results did not significantly differ by age, race, time period, or number of prior pregnancies. Having a prior pregnancy (delivery date>1year ago) was also associated with a first-time symptomatic kidney stone (OR, 1.27; P=0.01). LIMITATIONS: Observational study design in a predominantly White population. The exact timing of stone formation cannot be determined. CONCLUSIONS: Pregnancy increases the risk of a first-time symptomatic kidney stone. This risk peaks close to delivery and then improves by 1 year after delivery, though a modest risk of a kidney stone still exists beyond 1 year after delivery.

Estimating the health-related quality of life of kidney stone patients: initial results from the Wisconsin Stone Quality of Life Machine-Learning Algorithm (WISQOL-MLA).

OBJECTIVE: To build the Wisconsin Stone Quality of Life Machine-Learning Algorithm (WISQOL-MLA) to predict urolithiasis patients' health-related quality of life (HRQoL) based on demographic, symptomatic and clinical data collected for the validation of the Wisconsin Stone Quality-of-Life (WISQOL) questionnaire, an HRQoL measurement tool designed specifically for patients with kidney stones. MATERIAL AND METHODS: We used data from 3206 stone patients from 16 centres. We used gradient-boosting and deep-learning models to predict HRQoL scores. We also stratified HRQoL scores by quintile. The dataset was split using a standard 70%/10%/20% training/validation/testing ratio. Regression performance was evaluated using Pearson's correlation. Classification was evaluated with an area under the receiver-operating characteristic curve (AUROC). RESULTS: Gradient boosting obtained a test correlation of 0.62. Deep learning obtained a correlation of 0.59. Multivariate regression achieved a correlation of 0.44. Quintile stratification of all patients in the WISQOL dataset obtained an average test AUROC of 0.70 for the five classes. The model performed best in identifying the lowest (0.79) and highest quintiles (0.83) of HRQoL. Feature importance analysis showed that the model weighs in clinically relevant factors to estimate HRQoL, such as symptomatic status, body mass index and age. CONCLUSIONS: Harnessing the power of the WISQOL questionnaire, our initial results indicate that the WISQOL-MLA can adequately predict a stone patient's HRQoL from readily available clinical information. The algorithm adequately relies on relevant clinical factors to make its HRQoL predictions. Future improvements to the model are needed for direct clinical applications.

Stent duration and increased pain in the hours after ureteral stent removal.

INTRODUCTION To assess the relationship between pain after ureteral stent removal and patient and procedural factors. MATERIALS AND METHODS: A validated survey designed to assess the relationship between quality of life and treatment decisions in kidney stone disease was randomly distributed to patients with a history of a ureteral stent in seven medical centers across North America participating in an endourology research collaborative between July 2016 and June 2018. The primary outcome was increased pain after ureteral stent removal. Statistical analyses were performed using Chi-square and multiple logistic regression. RESULTS: A total of 327 surveys were analyzed. Twenty seven percent of patients reported increased pain in the hours after ureteral stent removal. Patients with a stent ≤ 7 days were significantly more likely to experience pain after stent removal compared to those with a stent > 7 days (33.3% versus 22.8%, p = 0.04). Female gender (OR: 2.41, 95% CI: 1.42-4.10) was associated with increased pain after stent removal, while increasing age was inversely associated (OR: 0.52, 95% CI: 0.36-0.74). After adjustment, patients with a stent > 7 days were significantly less likely to report pain in the hours after removal (OR: 0.59, 95% CI: 0.35-0.99). CONCLUSIONS: Approximately one in four patients will experience increased pain after ureteral stent removal. Female patients, younger patients, and patients with a stent ≤ 7 days were more likely to experience an increase in pain immediately following stent removal. Understanding factors associated with post-stent removal pain may be helpful in counseling patients at high risk stent removal morbidity.

Kidney stones and the opioid epidemic: recent developments and review of the literature.

PURPOSE OF REVIEW: A public health emergency has been declared in response to rising opioid addiction and opioid-related deaths in the United States. As kidney stones have been identified as an important source of initial and repeated opioid exposures, this review seeks to describe the scope of the problem and report relevant alternatives to opioid analgesia for stones. RECENT FINDINGS: Recent literature summarizing the extent of opioid use among those with stones is reviewed. A number of opioid-minimizing strategies and analgesic regimens have been proposed and studied. A review of these modifications and alternatives is provided. SUMMARY: Both symptomatic renal colic and surgical interventions to address stones may prompt need for analgesia. Reducing prescribed opioids reduces both patient use and risk of diversion. Modifications in surgical technique, administration of local anesthetics, and use of systemic nonopioid analgesics have all been successfully employed.

Implications of Erdheim-Chester disease and percutaneous renal access.

Erdheim-Chester disease (ECD) is a rare systemic histiocytosis with urologic manifestations in a majority of affected patients. An important manifestation is a pronounced retroperitoneal fibrosis with reported dense inflammatory rind surrounding the kidneys. We report a case of a patient with large stone burden necessitating percutaneous nephrolithotomy and the implications related to his Erdheim-Chester-related retroperitoneal fibrotic changes. Foreknowledge of these implications may inform perioperative counseling and surgical planning to maximize opportunity for successful outcomes.

Understanding the relationship between health insurance and kidney stones: an examination of NHANES data.

INTRODUCTION: To investigate the relationship between socioeconomic factors, specifically insurance status, and kidney stones using a nationally representative cohort. MATERIALS AND METHODS: A retrospective secondary data analysis of National Health and Nutrition Examination Survey (NHANES) data from 2007 to 2014 was performed. Using univariate statistics and multiple logistic regressions, we examined the relationship between socioeconomic factors and kidney stone history. RESULTS: The weighted national prevalence of nephrolithiasis between ages 20 and 64 was 7.7% of a population of over 95.3 million. Fifty-three percent of the total population was female. The mean age was 42 years and the mean body mass index (BMI) was 28.7. The prevalence of nephrolithiasis was higher among individuals who had state-assisted insurance compared to those with private insurance (10.3% versus 7.3%, p = 0.005). On univariate regression analysis, having a college education was protective against stones compared to having less than a high-school degree (OR 0.62, 95% CI 0.43-0.84; p = 0.009). Income was also significantly associated with kidney stone prevalence. After adjusting for race, BMI, gender, water intake, income, and education level through multivariable analysis, having private insurance was associated with lower odds of developing nephrolithiasis compared to having state-assisted insurance (OR 0.62, 95% CI 0.44-0.89; p = 0.01). CONCLUSIONS: Individuals with state-assisted insurance were found to have significantly increased odds of a kidney stone compared to those with private insurance. Urologists, primary care, and policy makers should recognize this disparity exists and target opportunities to elucidate mechanisms and provide intervention for this high-risk group.

Symptomatic and Radiographic Manifestations of Kidney Stone Recurrence and Their Prediction by Risk Factors: A Prospective Cohort Study.

BACKGROUND: Meaningful interpretation of changes in radiographic kidney stone burden requires understanding how radiographic recurrence relates to symptomatic recurrence and how established risk factors predict these different manifestations of recurrence. METHODS: We recruited first-time symptomatic stone formers from the general community in Minnesota and Florida. Baseline and 5-year follow-up study visits included computed tomography scans, surveys, and medical record review. We noted symptomatic recurrence detected by clinical care (through chart review) or self-report, and radiographic recurrence of any new stone, stone growth, or stone passage (comparing baseline and follow-up scans). To assess the prediction of different manifestations of recurrence, we used the Recurrence of Kidney Stone (ROKS) score, which sums multiple baseline risk factors. RESULTS: Among 175 stone formers, 19% had symptomatic recurrence detected by clinical care and 25% detected by self-report; radiographic recurrence manifested as a new stone in 35%, stone growth in 24%, and stone passage in 27%. Among those with a baseline asymptomatic stone (54%), at 5 years, 51% had radiographic evidence of stone passage (accompanied by symptoms in only 52%). Imaging evidence of a new stone or stone passage more strongly associated with symptomatic recurrence detected by clinical care than by self-report. The ROKS score weakly predicted one manifestation-symptomatic recurrence resulting in clinical care (c-statistic, 0.63; 95% confidence interval, 0.52 to 0.73)-but strongly predicted any manifestation of symptomatic or radiographic recurrence (5-year rate, 67%; c-statistic, 0.79; 95% confidence interval, 0.72 to 0.86). CONCLUSIONS: Recurrence after the first stone episode is both more common and more predictable when all manifestations of recurrence (symptomatic and radiographic) are considered.

Association of Patient Age and Gender with Kidney Stone Related Quality of Life.

PURPOSE: Kidney stone formers have lower health related quality of life than nonstone formers. The North American Stone Quality of Life Consortium is a multicenter, longitudinal, prospective study of health related quality of life in patients with kidney stones using the WISQOL (Wisconsin Stone Quality of Life Questionnaire) with data on 2,052 patients from a total of 11 centers. This study is a subanalysis of cross-sectional data looking at the association of age, gender and race on health related quality of life of stone formers. MATERIALS AND METHODS: We performed multivariable analyses of ordinal logistic regression analyses to determine the impact of age, gender and race on health related quality of life, adjusting for other baseline covariates. The proportional odds assumption of ordinal logistic regression was checked. Total score and scores on 4 subdomains (social functioning, emotional functioning, stone related impact and vitality) were included. RESULTS: Median total score for all patients was 80.4. On multivariable analysis older patients had a significantly higher total health related quality of life score than younger patients (per 10-year increase OR 1.25, p <0.0001). Male patients had higher scores than females (OR 1.56, p = 0.0003) and nonCaucasian patients had lower health related quality of life than nonLatino Caucasian patients (OR 0.63, p = 0.0045). CONCLUSIONS: Younger and female patients with kidney stones have lower health related quality of life than older and male patients, respectively. NonCaucasian patients with stones also have lower health related quality of life. The clinical impact of these findings might include future implications for patient counseling, including dietary and medical management of stone disease, and potential changes to the paradigm of the surgical management of stones.

Low Income and Nonwhite Race are Strongly Associated with Worse Quality of Life in Patients with Nephrolithiasis.

PURPOSE: Kidney stones are a source of significant morbidity which have been shown to negatively impact health related quality of life. We sought to understand the association between health related quality of life, socioeconomic status and race among patients with kidney stones. MATERIALS AND METHODS: Patients with stones at a total of 11 stone centers across the United States completed the WISQOL (Wisconsin Stone Quality of Life questionnaire). The patient ZIP Code™ was used to estimate household income. A mixed effects regression model was constructed for analysis with ZIP Code as the random intercept. RESULTS: A total of 2,057 stone formers completed the WISQOL. Lower income was independently associated with significantly lower health related quality of life (ß = 0.372, p = 0.014), as were nonwhite race (ß = -0.299, p = 0.001), unemployed work status (ß = -0.291, p = 0.008), female gender (ß = -0.204, p <0.001), body mass index greater than 40 kg/m2 (ß = -0.380, p <0.001), 5 or more medical comorbidities (ß = -0.354, p = 0.001), severe recurrent stone formation (ß = -0.146, p = 0.045), enrollment at an acute care visit, or a preoperative or postoperative appointment (ß = -0.548, p <0.001) and recent stone symptoms (ß = -0.892, p <0.001). CONCLUSIONS: Lower income, nonwhite race and unemployed work status were independently associated with lower health related quality of life among patients with kidney stones. While clinical characteristics such as body mass and stone disease severity were also associated with health related quality of life, this study shows that socioeconomic factors are similarly important. Further research to understand the specific mechanisms by which socioeconomic status and race impact health may lend insight into methods to optimize clinical treatment of stone formers and patients with other chronic diseases.

Leave no stone unturned: defining recurrence in kidney stone formers.

PURPOSE OF REVIEW: Established guidelines provide recommendations on the management of kidney stones to prevent recurrence. However, clear and clinically useful terminology for recurrence of kidney stones is needed. This review describes the various manifestations of kidney stone recurrence and the reported rates of kidney stone recurrence in various clinical settings. RECENT FINDINGS: Kidney stone recurrence has a wide range of symptomatic and radiographic presentations. Symptomatic recurrence may include characteristic symptoms of stone passage via the ureter (renal colic and gross hematuria). This may be self-managed or result in clinical care, with or without confirmation of an obstructing stone on imaging. Radiographic recurrence has been variably defined as new stone formation, stone growth, or stone disappearance (from passage with or without symptoms). Studies have used inconsistent definitions of recurrence, and recurrence rates vary substantially. Stone free rates and residual stone fragment size after surgical interventions are useful predictors of symptomatic recurrence. SUMMARY: The recurrence rate of kidney stones has been assessed in stone formers from sub-specialty clinics, the general community, and clinical trials. The definition of recurrence is quite heterogenous between studies, but the rate of recurrence generally increases as more manifestations are included in the definition.

The association of nephrolithiasis with prescription opioid use
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OBJECTIVE: To characterize opioid utilization among those with nephrolithiasis in a national cohort. MATERIALS AND METHODS: We performed cross sectional analysis of participants in the Medical Expenditure Panel Surveys during 2008 - 2014. Sample weights were employed for analysis of complex survey design. Those reporting occurrence of "renal or ureteral calculus" during the survey period represented the cohort of stone formers (SFs). Receipt of opioid prescription as well as total number of opioid prescriptions filled over study period were noted. RESULTS: Of 65,397 adult participants - weighted to represent 209,043,539 - 1.29% reported occurrence of nephrolithiasis. SFs were older, had higher BMI, and higher likelihood of depression and anxiety. Compared with those without nephrolithiasis, SFs had higher prevalence of opioid use (59.5 vs. 20.2%, p < 0.0001). On multivariate analysis, the odds of receiving an opioid prescription were increased greater than 5 times in SFs compared with those without stones (OR 5.61, 95% CI 4.59 - 6.85). Assessing each individual's total number of opioid prescriptions revealed SFs had a greater mean number of opioid prescriptions filled than those without nephrolithiasis (2.53 vs. 0.97, p < 0.001). Among SFs receiving opioids, depression and anxiety were both associated with a significantly greater number of opioid prescriptions (6.80 vs. 3.66, p < 0.001; and 8.91 vs. 3.38, p = 0.008, respectively). CONCLUSION: A majority of those with renal stone occurrence receive prescription opioids. Of particular note, the presence of either depression or anxiety is associated with larger total number of opioid prescriptions over the study period.
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Gender Equivalence in the Prevalence of Nephrolithiasis among Adults Younger than 50 Years in the United States.

PURPOSE: Although urolithiasis affects each gender, conventional teaching proposes that men are 3 times more likely to have stones. However, clinical practice refutes such a disparity, particularly among working age adults. Small studies have suggested an erosion of this gender gap. Therefore, we examined the relationship between gender and stone prevalence among American adults younger than 50 years. MATERIALS AND METHODS: We analyzed the NHANES (National Health and Nutrition Examination Survey) 2007 to 2012 cohort. Weighted proportions and multivariate logistic regression of the cohort and pertinent subgroups were assessed to determine the prevalence and the odds of nephrolithiasis. RESULTS: The cohort of 17,658 subjects, which was weighted to represent the American population of 218,828,951 adults, was 48.1% male. In our cohort of 8,888 adults weighted to represent 123,976,786 subjects younger than 50 years, which was 49.3% male and 50.7% female, there was no difference in stone prevalence (6.3% in males and 6.4% in females, p = 0.85). On unadjusted logistic regression of those younger than 50 years men were no more likely to report a stone history (OR 0.98, p = 0.85). Multivariate logistic regression adjusting for diabetes, obesity, ethnicity, age, and water, sodium and protein intake confirmed no difference in stone prevalence between the genders (OR 1.1, p = 0.51). CONCLUSIONS: Among adults of working and child rearing ages in the United States the much touted gender disparity in nephrolithiasis is not present. Prior assessments of gender based stone prevalence may have failed to specifically assess this economically critical demographic or there may in fact be an ongoing epidemiological change. Recognition that women are as likely as men to form stones in this cohort suggests the need to better elucidate the pathophysiology of stones in women.

Conversion from Cystine to Noncystine Stones: Incidence and Associated Factors.

PURPOSE: Patients with cystinuria are often treated with medical alkalization and shock wave lithotripsy, although each treatment is hypothesized to increase the risk of calcium phosphate stones. We performed a multicenter retrospective review to evaluate whether stones of another composition develop in patients with cystinuria and with what frequency. MATERIALS AND METHODS: We retrospectively reviewed the records of a multi-institutional cohort of patients with cystinuria. We assessed medications, stone analyses, 24-hour urinalyses and types of procedures. We compared patients who formed only cystine stones vs those with noncystine stones. RESULTS: We identified 125 patients from a total of 5 institutions who were followed a mean of 5.2 years (range 0 to 26). Stones with noncystine components were submitted by 37 patients (29.6%). Potassium citrate medication was not associated with a noncystine composition (p = 0.1877). Regarding surgical management 18 patients (13%) underwent at least 1 shock wave lithotripsy session (range 0 to 9) and 79 (63%) underwent percutaneous nephrolithotomy at least once (range 0 to 10). When stratified based on pure cystine vs converted stones, the average total number of shock wave lithotripsy and percutaneous nephrolithotomy procedures was higher in the group with cystine and subsequent noncystine stone compositions (0.94 vs 0.10, p <0.0001, and 1.7 vs 1.5, p = 0.0053, respectively). On logistic regression male gender (OR 3.1, p = 0.0280) and the number of shock wave lithotripsy sessions (OR 3.0, p = 0.0170) were associated with an increased likelihood of the development of stones with a noncystine composition. CONCLUSIONS: Stones with noncystine components develop in more than 25% of patients with cystinuria, underscoring the importance of continued stone analysis. In this study prior shock wave lithotripsy was associated with conversion to a noncystine stone composition while urinary alkalization therapy was not associated.

A Randomized Controlled Trial of Preoperative Prophylactic Antibiotics Prior to Percutaneous Nephrolithotomy in a Low Infectious Risk Population: A Report from the EDGE Consortium.

PURPOSE: Single institution studies suggest a benefit of a week of preoperative antibiotics prior to percutaneous nephrolithotomy. These studies are limited by lower quality methodology, such as the inclusion of heterogeneous populations or nonstandard definitions of sepsis. The AUA (American Urological Association) Best Practice Statement recommends less than 24 hours of intravenous antibiotics but to our knowledge no other data exist on the duration or benefit of preoperative antibiotics. Using CONSORT (Consolidated Reporting of Trials) guidelines we sought to perform a rigorous multi-institutional trial to assess preoperative antibiotics in patients in whom percutaneous nephrolithotomy was planned and who were at low risk for infection. MATERIALS AND METHODS: This randomized controlled trial enrolled patients undergoing percutaneous nephrolithotomy who were at low risk, defined as negative preoperative urine cultures and no urinary drain. Of the subjects 43 were randomized to nitrofurantoin 100 mg twice daily for 7 days preoperatively while a control arm of 43 received no oral antibiotics. All subjects received perioperative doses of ampicillin and gentamicin. Prone percutaneous nephrolithotomy was performed by urologists blinded to randomization. The primary outcome was the development of sepsis. RESULTS: A total of 86 subjects were enrolled. Preoperative patient characteristics were similar in the treatment and control cohorts with a stone size of 19 and 17 mm, respectively (p = 0.47). Intraoperative characteristics also did not differ. The sepsis rate was not statistically different between the treatment and control groups (12% and 14%, respectively, 95% CI -0.163-0.122, p = 1.0). Other infectious parameters and complications were similar, including intensive care admission, fever, hypotension and leukocytosis. CONCLUSIONS: Our study demonstrated no advantage to providing 1 week of preoperative oral antibiotics in patients at low risk for infectious complications who undergo percutaneous nephrolithotomy. Perioperative antibiotics according to the AUA Best Practice Statement appear sufficient.

The Effect of Thiazide and Potassium Citrate Use on the Health Related Quality of Life of Patients with Urolithiasis.

PURPOSE: To our knowledge it is unknown whether the benefits of medical management of urolithiasis outweigh the potential side effects of the medications used, including potassium citrate and thiazide diuretics. Therefore, we evaluated the relationship between potassium citrate or thiazides and overall stone related health related quality of life. MATERIALS AND METHODS: Cross-sectional data were obtained on stone forming enrollees in the North American Stone Quality of Life Consortium. We used the WISQOL (Wisconsin Stone Quality of Life) questionnaire to compare health related quality of life between patients treated and not treated with potassium citrate or thiazide type diuretics. Additionally, the likelihood of gastrointestinal complaints was compared between those prescribed and not prescribed potassium citrate. The likelihood of fatigue and sexual complaints was also compared in those prescribed and not prescribed thiazides. RESULTS: Of the 1,511 subjects, including 787 males and 724 females, 279 were on potassium citrate and 238 were on thiazides at study enrollment. Patients prescribed potassium citrate had higher health related quality of life in each domain vs those not prescribed potassium citrate (p <0.001). Patients prescribed thiazides had higher health related quality of life in each domain compared to those not prescribed thiazide (all p <0.01). Those prescribed potassium citrate were less likely than those not prescribed potassium citrate to report nausea, stomach upset or cramps (OR 0.57, p <0.001). Patients prescribed thiazides were less likely than those not prescribed thiazides to report fatigue (OR 0.63, p = 0.004) or reduced sexual interest and/or activity (OR 0.64, p = 0.005). CONCLUSIONS: Among stone formers the use of potassium citrate and thiazides was associated with better health related quality of life across all WISQOL domains without an increased likelihood of gastrointestinal complaints and fatigue or sexual complaints, respectively. These findings may be useful when counseling patients regarding the initiation of potassium citrate or thiazides for medical management of nephrolithiasis.

Changing incidence of factitious renal stone disease
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PURPOSE: We sought to describe patterns of factitious urinary stone submission over time by investigating a contemporary stone analysis database and comparing two distinct time points. MATERIALS AND METHODS: We retrospectively reviewed a single stone analysis lab database at two time points, 1990 and 2010, and compared total incidence of factitious stone submission, as well as gender patterns and type of factitious stone submitted. RESULTS: A total of 27,014 stones were analyzed, 16,216 (60%) from 1990 and 10,798 (40%) from 2010 with a decrease in total incidence from 2.6% (428/16,216) in 1990 to 1.2% (131/10,798) in 2010 (p < 0.001). In 1990, women were significantly more likely to submit a factitious stone (RR 1.5, 95% CI 1.4 - 1.7, p < 0.001), while in 2010 there was no gender difference (RR 0.9, 95% CI 0.8 - 1.03, p < 0.05). Plant material and geologic material represented the most common factitious stone types respectively, in both 1990 and 2010. CONCLUSION: In the largest contemporary review of spurious urinary stones, we find a decreased incidence and increased gender equivalence of factitious urinary stones in 2010 compared to 1990.
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"Allergic-like" reaction risk in patients undergoing non-intravenous contrast urography.

INTRODUCTION: Though widely performed, the safety of non-intravenous contrast (NIVC) urography in patients with documented intravenous, iodinated contrast allergic like reactions (ICA) is unclear. The purpose of this study was to determine the risk of "allergic-like" reaction (ALR) events in patients with ICA undergoing NIVC urography. MATERIALS AND METHODS: Patients undergoing contrast urography at a single institution were identified between 2011-2014. Patient charts were reviewed for documented ICA prior to index surgery, preoperative allergy prophylaxis with steroid or antihistamine, and acute allergic reactions identified by ICD codes within 24 hours of surgery. RESULTS: A total of 2,650 patients were included, 1,325 female (50%). Of these patients, 113 (4.2%) had an ICA. Overall 33% (37/113) of patient received preoperative allergy prophylaxis with a steroid or antihistamine. A potential ALR related ICD-9 code was identified in one patient (0.8%) with a prior IVC ALR without allergy prophylaxis within 24 hours preoperatively undergoing percutaneous nephrolithotomy (PCNL). This event was found to be an associated with a myocardial infarction and lacked ALR sequelae. CONCLUSION: Despite commonly voiced concerns, in this large series of over 2,500 patients, including 113 patients with a prior history of ICA undergoing contrast urography, only one patient was found to have a potential ALR event following PCNL. No patients undergoing a retrograde contrast urography with prior, documented ICA had a NIVC ALR event despite a low rate of pretreatment with corticosteroid or antihistamine.