Adam Kadlec

Metabolic Syndrome and Urinary Stone Composition: What Factors Matter Most?

OBJECTIVE To determine which metabolic syndrome (MetS) factors lead to differences in stone composition in a multivariate analysis. METHODS We retrospectively reviewed medical charts of patients who had a kidney stone removed over a 5-year period (2006-2011). MetS factors (obesity [body mass index {BMI} >30], diabetes mellitus [DM], hypertension [HTN], and dyslipidemia [DLD]) were tallied in each patient. For the latter 3 factors, medical treatment for the condition was used to tag a patient with the condition. Stone composition was determined by the dominant (>50%) component. Statistical analysis was designed to determine which MetS factors were independently associated with differences in stone composition. RESULTS Five hundred ninety kidney stones were included in the analysis. Patients with MetS had a higher prevalence of uric acid stones and lower prevalence of calcium phosphate stones. HTN and DM were independently associated with differences in composition, specifically uric acid stones (higher proportion), and calcium phosphate stones (lower proportion). Obesity was not associated with differences in composition, although a secondary analysis of morbidly obese patients showed a higher proportion of uric acid stones and a lower proportion of calcium oxalate stones. CONCLUSION HTN and DM are the MetS factors independently associated with differences in stone composition, specifically the uric acid and calcium phosphate components. Obesity has little effect on stone composition until a very high (>40) BMI is reached. The overall effect of MetS factors on stone type is relatively small, because most stones are calcium oxalate and MetS factors have little impact on calcium oxalate frequency.

Five-year experience with metallic stents for chronic ureteral obstruction.

PURPOSE We present 5 years of outcome data on metallic ureteral stents in a cohort of patients treated for chronic ureteral obstruction. MATERIALS AND METHODS We retrospectively identified and analyzed the records of all patients in whom a Resonance® Metallic Ureteral Stent was placed between early 2007 and late 2011 at our institution. We performed a descriptive analysis of key outcomes, including the failure and death rates, and stenting duration, defined as the time from initial stent placement to last stent failure or patient death. We also performed a secondary comparative analysis of patients with a benign vs malignant etiology of obstruction. RESULTS A total of 139 metallic stents were placed in 47 patients, including 27 (57%) with malignant and 20 (43%) with a benign etiology. Of the patients 15 (32%) had bilateral obstruction. Maximum followup was 59 months (mean 20, median 13, IQR 4-31). Stent failure occurred in 13 patients (28%), including 4 in the benign and 9 in the malignant group (p = 0.35). The median duration of stenting for benign and malignant obstruction was 22 (IQR 9-39) vs 7 months (IQR 3-25) (p = 0.106). Stenting duration was equivalent when controlling for the higher death rate in the malignant group. CONCLUSIONS Resonance metallic stents are an adequate management strategy for benign and malignant ureteral obstruction. A subset of patients in each group continued to do well at more than a 3-year overall duration of stenting. Failure rates were similar for benign and malignant etiologies.

Readability of Websites Containing Information About Prostate Cancer Treatment Options

PURPOSE Approximately 90 million American adults have literacy skills that test below a high school reading level. Websites written above this level can pose a challenge for those seeking online information about prostate cancer treatment options. In this study we determine the readability of selected websites using a systematic search process and validated readability formulas. MATERIALS AND METHODS We identified the 3 most popular keywords from 513 terms related to prostate cancer treatment options. We then systematically collected 270 websites from the top 3 search engines, and excluded from study those that were nonEnglish, not primarily text, irrelevant and/or duplicated. We used the Flesch-Kincaid grade level and Flesch Reading Ease to determine scores for each site. RESULTS A total of 62 unique websites were analyzed. Median Flesch-Kincaid grade level was 12.0 (range 8.0 to 12.0) and median Flesch Reading Ease score was 38.1 (range 0.0 to 65.5). Only 3 sites (4.8%) were written below a high school reading level (less than 9.0). CONCLUSIONS Few websites with discussions on prostate cancer treatment options are written below a high school reading level. This is problematic for a third of Americans who seek to further educate themselves using online resources. Clinicians can use this information to guide their patients to appropriate websites.

Effect of renal function on urinary mineral excretion and stone composition.

OBJECTIVE To determine the effect of renal function on urinary mineral stone excretion and composition of kidney stones in patients undergoing urologic intervention for nephrolithiasis. METHODS We performed a retrospective analysis of 158 patients with 193 kidney stones who underwent endourologic intervention for nephrolithiasis. The patients were grouped by the estimated glomerular filtration rate (eGFR). The kidney stone composition and results of the 24-hour urinalysis were reported for each group. Statistical analysis was performed using the chi-square test, Kruskal-Wallis test, and analysis of variance. RESULTS The kidney stone composition profile differed significantly between the groups, with uric acid stones associated with a lower eGFR and calcium phosphate stones associated with a greater eGFR. A lower eGFR correlated with lower urine pH, lower calcium excretion, and greater oxalate excretion. Excretion of uric acid and the body mass index did not differ between groups. CONCLUSION Different degrees of renal function correlated with certain types of kidney stones. The urine pH was lower in patients with impaired renal function. Renal function might be an underappreciated factor that affects kidney stone composition and urinary mineral excretion.

Contemporary Volume–Outcome Relationships for Percutaneous Nephrolithotomy: Results from the Nationwide Inpatient Sample

INTRODUCTION/OBJECTIVE We sought to examine the contemporary relationship between case volume and outcome for percutaneous nephrolithotomy (PCNL) using a publically available administrative database. METHODS A weighted sample of 7785 patients was obtained from the 2010 Healthcare Cost and Utilization Project (HCUP) Nationwide Inpatient Sample (NIS). ICD-9-CM diagnostic codes were used to identify patients with urolithiasis (592.0, 592.1, and 592.9) who underwent percutaneous nephrostomy with fragmentation (5504). Charlson Comorbidity Indices (CCI) were calculated based on diagnostic codes for all patients. Hospital case volume was quartile classified and we then compared key outcomes (the complication rate, transfusion rate, length of stay [LOS], and in-hospital mortality rate) by volume quartile. We then performed multivariate analysis to examine the effect of CCI, annual volume, and age on key outcomes. RESULTS The overall complication rate was 17% in the weighted sample. In univariate analysis, statistically significant variation in the complication rate, CCI, transfusion rate, and in-hospital mortality was noted with regard to the hospital volume. The complication rate and transfusion rates varied by case volume, but in a nonlinear fashion, wherein rates were highest at the lowest and highest volume centers. CCI was strongly predictive (p<0.001) of complications and LOS in the multivariate analysis. Case volume was only predictive (p=0.042) of LOS in the multivariate analysis. CONCLUSION Annual case volume of the treating center was associated with shorter LOS after PCNL, but case volume was not independently predictive of complication or transfusion in multivariate analysis. CCI was a strong independent predictor of complication and LOS.

Open Versus Robotic Radical Prostatectomy in Obese Men

Objectives: Robotic-assisted radical prostatectomy (RARP) has been shown to reduce blood loss, peri-operative complications and length of stay when compared to open radical prostatectomy (ORP). We sought to determine whether the reported benefits of RARP over ORP translate to obese patients. Patients and Methods: We utilized the 2009-2010 Nationwide Inpatient Sample to identify all obese men with prostate cancer who underwent ORP and RARP. Our primary outcome was the presence of a peri-operative adverse event (i.e. blood transfusion, complication, prolonged length of stay). We fit multivariable logistic regression models to examine whether RARP in obese patients was independently associated with decreased odds of all three outcomes. Results: We identified 9,108 obese patients who underwent radical prostatectomy. On multivariable analysis, the use of RARP in the obese population was not independently associated with decreased odds of developing a peri-operative complication (OR = 0.81, CI: 0.58-1.13, p = 0.209). RARP was, however, associated with decreased odds of blood transfusion (OR = 0.17, CI: 0.10-0.30, p < 0.001) and prolonged length of stay (OR = 0.28, CI: 0.20-0.40, p < 0.001). Conclusion: Our findings suggest that in obese patients, the use of RARP may reduce length of stay and blood transfusions compared to ORP. Both approaches, however, are associated with similar odds of developing a complication.

Comparison of complication rates for unilateral and bilateral percutaneous nephrolithotomy (PCNL) using a modified Clavien grading system

Whats known on the subject? and What does the study add?

Cost Analysis of Metallic Stents for Chronic Ureteral Obstruction: A Multicenter Study

Introduction: Metallic and polymer ureteral stents are used to manage chronic ureteral obstruction. In general, metallic stents are more costly than polymer stents but they are changed less frequently. We examined the overall costs of using these stent types at 2 institutions. Methods: We identified all patients in whom a metallic stent was placed at 2 academic institutions between July 2007 and July 2013. We calculated the average time to stent exchange or failure and the overall cost of metallic and polymer stent use. Costs included those associated with materials, operating room services, anesthesia and other expenses. Results: We identified 86 patients in whom a total of 230 metallic stents were placed. Time to stent failure or exchange of a metallic stent was 7.4 months. The per unit cost of a polymer stent and a metallic stent was

PD14-03 POST-ACUTE CARE AS A DRIVER OF EPISODE COST VARIATION FOR AMBULATORY STONE SURGERY

121 and

Update on the Evaluation of Repeated Stone Formers

887, respectively. The average annual cost of unilateral and bilateral metallic stents was