Low Urine pH Research Articles

MP10-03 INFLUENCE OF SGLT2 INHIBITORS ON 24-HOUR URINE PARAMETERS AMONG KIDNEY STONE PATIENTS IN THE MEDICARE POPULATION

You have accessJournal of UrologyCME1 Apr 2023MP10-03 INFLUENCE OF SGLT2 INHIBITORS ON 24-HOUR URINE PARAMETERS AMONG KIDNEY STONE PATIENTS IN THE MEDICARE POPULATION Joseph Crivelli, Ryan Hsi, Mary Oerline, John Asplin, Naim Maalouf, and John M Hollingsworth Joseph CrivelliJoseph Crivelli More articles by this author , Ryan HsiRyan Hsi More articles by this author , Mary OerlineMary Oerline More articles by this author , John AsplinJohn Asplin More articles by this author , Naim MaaloufNaim Maalouf More articles by this author , and John M HollingsworthJohn M Hollingsworth More articles by this author View All Author Informationhttps://doi.org/10.1097/JU.0000000000003225.03AboutPDF ToolsAdd to favoritesDownload CitationsTrack CitationsPermissionsReprints ShareFacebookLinked InTwitterEmail Abstract INTRODUCTION AND OBJECTIVE: Sodium/glucose cotransporter 2 inhibitors (SGLT2is) are widely used for patients with type 2 diabetes. Recent epidemiologic studies have shown a reduction in stone events in diabetic patients treated with SGLT2is, but changes in urine chemistries that may account for this have not been identified. The purpose of this study was to evaluate the effect of SGLT2is on urine chemistry and supersaturation among patients with kidney stone disease. METHODS: From a Medicare-Litholink database (years 2010-2018), we identified patients who received two, 24-hour urine tests, of which the first was performed without SGLT2i use, and the second was collected during SGLT2i use. Patients were excluded if they started using alkali citrate, thiazide, or xanthine oxidase inhibitor between the two collections, and excluded if the creatinine excretions in the 2 collections differed by >30%. Bivariate comparisons using the t-test were compared between 24-hour urine variables with p<0.05 considered statistically significant. RESULTS: Among 30 patients identified, the cohort had mean±SD age 66.6±8.9 years, 80% were male, and all with Medicare Part A/B available information (n=24) had a baseline diagnosis of diabetes mellitus type 2. The SGLT2i used included canagliflozin (in 56.7%), dapagliflozin (20.0%), and empagliflozin (23.3%). The mean±SD time from the first to second collection was 18.5±17.4 months. Comparison of 24-hour parameters between the first collection (pre-SGLT2i) and the second collection (on SGLT2i) is shown in the Table 1. Notable findings include a trend to higher 24-hour urine volume by 0.38 L/day (p=0.065), and significantly lower urine pH (p=0.046), with non-significant changes in urine excretion rate of calcium, oxalate, citrate, uric acid, and phosphorus. This resulted in a significant reduction in urine supersaturation with respect to calcium phosphate (likely from combination of greater urine volume and slightly lower pH), but non-significant changes in SS calcium oxalate and uric acid. CONCLUSIONS: Chronic SGLT2i use is associated with a lower urine pH with non-significant changes in volume and the excretion of major stone-related electrolytes. Larger studies are needed to confirm these findings and explore the impact of SGLT2i on stone recurrence rate. Source of Funding: Supported by National Institutes of Health Grant 1R01DK121709 © 2023 by American Urological Association Education and Research, Inc.FiguresReferencesRelatedDetails Volume 209Issue Supplement 4April 2023Page: e114 Advertisement Copyright & Permissions© 2023 by American Urological Association Education and Research, Inc.MetricsAuthor Information Joseph Crivelli More articles by this author Ryan Hsi More articles by this author Mary Oerline More articles by this author John Asplin More articles by this author Naim Maalouf More articles by this author John M Hollingsworth More articles by this author Expand All Advertisement PDF downloadLoading ...

Association between obstructive sleep apnea and 24-h urine chemistry risk factors for urinary stone disease

The effect of obstructive sleep apnea (OSA) on 24-h urine parameters and resultant kidney stone risk is unknown. We sought to compare urinary lithogenic risk factors among patients with kidney stone disease with and without OSA. We performed a retrospective cohort study of adult patients with nephrolithiasis undergoing both polysomnography and 24-h urine analysis. Measures of acid load including gastrointestinal alkali absorption, urinary titratable acid, and net acid excretion were calculated from 24-h urine. We performed univariable comparisons of 24-h urine parameters between those with and without OSA and fit a multivariable linear regression model adjusting for age, sex, and BMI. Overall, there were 127 patients who underwent both polysomnography and a 24-h urine analysis from 2006 to 2018. There were 109 (86%) patients with OSA and 18 (14%) without. Patients with OSA were more commonly male, had greater BMI and had higher rates of hypertension. Patients with OSA had significantly higher levels of 24-h urinary oxalate, uric acid, sodium, potassium, phosphorous, chloride, and sulfate; higher supersaturation of uric acid; higher titratable acid, and net acid excretion; and lower urinary pH and supersaturation of calcium phosphate (p < 0.05). The difference in urinary pH and titratable acid, but not net acid excretion, remained significant when adjusting for BMI, age, and gender (both p = 0.02). OSA is associated with changes in urinary analytes that promote kidney stone formation, similar to those observed with obesity. After accounting for BMI, OSA is independently associated with lower urine pH and increased urinary titratable acid.

Increasing Phosphorus Intake Reduces Urinary Concentrations of Magnesium and Calcium in Adult Ovariectomized Cats Fed Purified Diets

We assessed the phosphorus requirement of adult cats and the relationship between phosphorus intake and the fecal and urinary excretion of calcium, magnesium and phosphorus. Female cats (ovariectomized at the onset of sexual maturity) were fed purified diets containing 4.6, 9.2, 18.4 or 27.7 mmol phosphorus/MJ in a 4 × 4-wk crossover study. During the experiment, balance studies were performed and blood samples were taken. A dietary level of 4.6 mmol phosphorus/MJ was found to be sufficient to maintain phosphorus balance and normal plasma concentrations of phosphorus in the adult ovariectomized cats. Increasing levels of dietary phosphorus in the form of NaH2PO4·2H2O caused lower urinary pH values, lower urinary concentrations of calcium and magnesium, and higher urinary concentrations of phosphorus. When dietary levels of phosphorus were raised, the percentage of apparent absorption of magnesium was lower, whereas that of phosphorus was higher. Although it could be predicted that dietary phosphorus levels higher than the National Research Council recommendation of 9.2 mmol/MJ markedly reduced urinary struvite saturation, these higher levels are discouraged because they are associated with lower plasma phosphorus concentrations and creatinine clearance.

Urinary Risk Profile, Impact of Diet, and Risk of Calcium Oxalate Urolithiasis in Idiopathic Uric Acid Stone Disease.

The role of diet in the pathogenesis of uric acid (UA) nephrolithiasis is incompletely understood. This study investigated the effect of dietary intervention on the risk of UA stone formation under standardized conditions. Twenty patients with idiopathic UA stone disease were included in the study. Dietary intake and 24 h urinary parameters were collected on the usual diet of the patients and a standardized balanced mixed diet. Although urinary UA excretion did not change, the relative supersaturation of UA decreased significantly by 47% under the balanced diet primarily due to the significant increase in urine volume and pH. Urinary pH was below 5.8 in 85% of patients under the usual diet, and in 60% of patients under the balanced diet. The supersaturation of calcium oxalate declined significantly under the balanced diet due to the significant decrease in urinary calcium and oxalate excretion and the increase in urine volume. Dietary intervention is a key component in the management of UA nephrolithiasis. Urinary calcium and oxalate excretion should also be monitored in patients with pure UA calculi to reduce the risk of mixed stone formation with calcium oxalate. Lower urinary pH in UA stone patients can only be partially explained by diet.

Effect of Sugar Beet Pulp and Anionic Salts on Metabolic Status and Mineral Homeostasis during the Peri-Parturient Period of Dairy Sheep.

Sugar beet pulp is a popular by-product of sugar extraction; however, it can potentially cause depletion of Ca availability due to its oxalic content. The experiment examined the effect of sugar beet pulp and anionic salts administration during the dry period on the serum concentration of calcium, magnesium, phosphate, and potassium of dairy sheep. Eighty-seven sheep were divided into three groups (A, B, and C) according to their body condition score (BCS) and age at 40 days before the expected lambing. All groups received alfalfa hay, mixed grass straw, and a concentrate supplement. The concentrate fed to groups B and C contained sugar beet pulp. The nutritional value fed to all three groups was similar, except for Dietary Cation Anion Difference (DCAD). Animals of group A had a DCAD of +198 mEq/kg, animals of group B of +188 mEq/kg, and animals of group C were fed 20 gr/d ammonium chloride to achieve a negative DCAD (-52 mEq/kg). All groups were fed the same ration after lambing. Blood samples were collected 30 d, 20 d, 17 d, 14 d, 10 d, 7 d, and 4 d before lambing (a.p.), 6 h, 12 h, 24 h, 7 d, 10 d, and 15 d after lambing (p.p) for calcium, magnesium, phosphate, and potassium, and 30 d a.p., 7 d, and 15 d p.p. for beta hydroxybutyrate acid (BHBA) concentrations. Urine samples were also collected 20 d, 10 d, 4 d a.p., and 7 d p.p for the evaluation of pH levels. Ca levels of the control group decreased earlier and were lower at 4 d a.p. compared to those of group B and C. Additionally, the control group showed lower p values compared to group C at 20 d and 17 d a.p. P levels recovered earlier post parturition in young (age 1-1.5 years old) compared to older ewes. Group C had lower urine pH values throughout the pre-parturient period, reflecting the acidifying effect of the administered ammonium chloride, without any side effect on macromineral blood concentration. Feeding sugar beet pulp and systemic acidifying before parturition is considered safe and might even be beneficial in preventing hypocalcemia.

Differences of Uric Acid Transporters Carrying Extracellular Vesicles in the Urine from Uric Acid and Calcium Stone Formers and Non-Stone Formers.

Background: Low urine pH and volume are established risk factors for uric acid (UA) stone disease (UASD). Renal tubular epithelial cells exposed to an acidic pH and/or UA crystals can shed extracellular vesicles (EVs) into the tubular fluid, and these EVs may be a pathogenic biomarker of UASD. Methods: Urinary EVs bearing UA transporters (SLC2A9, SLC17A3, SLC22A12, SLC5A8, ABCG2, and ZNF365) were quantified in urine from UA stone formers (UASFs), calcium stone formers (CSFs), and age-/sex-matched non-stone formers (NSFs) using a standardized and published method of digital flow cytometry. Results: Urinary pH was lower (p < 0.05) and serum and urinary UA were greater (p < 0.05) in UASFs compared with NSFs. Urinary EVs carrying SLC17A3 and SLC5A8 were lower (p < 0.05) in UASFs compared with NSFs. Urinary EVs bearing SLC2A9, SLC22A12, SLC5A8, ABCG2, and ZNF365 were lower (p < 0.05) in CSFs than UASFs, while excretion of SLC17A3-bearing EVs did not differ between groups. Conclusion: EVs bearing specific UA transporters might contribute to the pathogenesis of UASD and represent non-invasive pathogenic biomarkers for calcium and UA stone risk.

Low urine pH: a new marker for contrast-associated acute kidney injury?

Low urine pH: a new marker for contrast-associated acute kidney injury?

Acidic urine is associated with poor prognosis in patients with bladder cancer undergoing radical cystectomy.

PurposeTo assess the prognostic value of acidic urine (low urine pH) in patients with bladder cancer undergoing radical cystectomy.Materials and methodsWe reviewed patients enrolled in the Seoul National University Prospectively Enrolled Registry for Urothelial Cancer-Cystectomy (SUPER-UC-Cx) who underwent radical cystectomy for bladder cancer between March 2016 and December 2020 at the Seoul National University Hospital. During this period, 368 patients were registered in our database. To eliminate confounding factors, we excluded patients diagnosed with non-urothelial cancer and end-stage renal disease.ResultsA total of 351 patients with a mean age of 69.8 ± 10.5 years and median follow-up of 16.0 months were eligible for the analysis. The mean preoperative urine pH was 6.0. The patients were divided into low (pH ≤ 5.5) and high (pH≥6.0) urine pH groups for comparison. All clinicopathological features, including the tumor size, grade, and stage were comparable between the low and high urine pH groups. A Cox regression analysis was performed to assess the independent effect of acidic urine on patient survival. A multivariate analysis showed that high T stage (T3-4) (hazard ratio (HR) 5.18, P<0.001), decreased renal function (estimated glomerular filtration rate <60 mL/min/1.73 m2) (HR 2.29, P=0.003), and low urine pH (≤5.5) (HR 1.69, P=0.05) were associated with shortened recurrence-free survival (RFS). Regarding the overall survival (OS), high T stage (T3-4) (HR 7.15, P<0.001) and low urine pH (≤5.5) (HR 2.66, P=0.029) were significantly associated with shortened survival. A Kaplan–Meier analysis demonstrated that the acidic urine group showed shorter RFS (P=0.04) and OS (P=0.028) than the other groups.ConclusionsAcidic urine was independently associated with reduced RFS and OS in patients with bladder cancer undergoing radical cystectomy. Acidic urine contributing to an acidic tumor environment may promote aggressive behavior in bladder cancer.

A pilot dynamic analysis of formative factors of nephrolithiasis related to metabolic syndrome: evidence in a rat model

Introduction and objective To examine the dynamic changes in the formative factors of nephrolithiasis and the final micromorphological changes in an obesity-initiated metabolic syndrome (MS) rat model. Methods Forty five-week-old male Sprague–Dawley (SD) rats were randomly divided into four groups: the regular diet group (RD), high-fat diet group (HFD), regular diet with drug (ethylene glycol and ammonium chloride) group (RDD), and high-fat diet with drug group (HFDD). A dynamic assessment of MS components (body weight (BW), body length (BL), Lee’s index (LI), blood glucose (BG), total cholesterol (TC), and triglycerides (TGs)) and stone-forming factors (urinary pH, urinary calcium, and urinary oxalate acid) was carried out. In addition, the levels of oxidative stress (OS) markers (CAT, SOD, TAC, GSH-PX, and MDA) were measured, and histological analysis was carried out at the end of 16 weeks. Results MS-related parameters, such as BW, LI, BG, TC, and TG, were significantly higher in HFD-fed rats than in RD-fed rats (p < 0.001). In the HFDD group, significantly lower urinary pH, hyperoxaluria, and hypocalciuria were noted in the dynamic assessment of stone-forming factors (p < 0.001). CAT, TAC, and MDA were notably changed in the HFD-fed groups, particularly the HFDD rats. Histological analysis showed that the renal tubules of HFDD rats had the highest scores for both inflammation and renal crystallization deposition (p < 0.05). Conclusions Our results suggest that male SD rats with MS are prone to developing nephrolithiasis. Validation in an in vivo model may lead to an understanding of the underlying pathophysiological mechanisms of action of MS-related nephrolithiasis in humans. Key messages Male SD rats with metabolic syndrome are more prone to developing calcium oxalate nephrolithiasis after treatment with ethylene glycol and ammonium chloride compared to control lean rats. MS-related nephrolithiasis in rats induced by ethylene glycol and ammonium chloride is mainly related to increased hyperoxaluria and inflammation and decreased antioxidant levels. High-fat diet-fed SD rats treated with ethylene glycol and ammonium chloride are a stable and valid in vivo model for understanding the potential mechanism of action of MS-related nephrolithiasis.

MP26-02 PREVALENCE OF 24-HOUR URINE ABNORMALITIES AMONG OLDER ADULTS WITH URINARY STONE DISEASE

You have accessJournal of UrologyCME1 May 2022MP26-02 PREVALENCE OF 24-HOUR URINE ABNORMALITIES AMONG OLDER ADULTS WITH URINARY STONE DISEASE Ryan Hsi, Mary Oerline, Joseph Crivelli, Vahakn Shahinian, and John Hollingsworth Ryan HsiRyan Hsi More articles by this author , Mary OerlineMary Oerline More articles by this author , Joseph CrivelliJoseph Crivelli More articles by this author , Vahakn ShahinianVahakn Shahinian More articles by this author , and John HollingsworthJohn Hollingsworth More articles by this author View All Author Informationhttps://doi.org/10.1097/JU.0000000000002569.02AboutPDF ToolsAdd to favoritesDownload CitationsTrack CitationsPermissionsReprints ShareFacebookLinked InTwitterEmail Abstract INTRODUCTION AND OBJECTIVE: While urinary stone disease (USD) is traditionally considered a condition affecting working age adults, its prevalence among the older population is increasing. Given physiologic and lifestyle differences between these two populations, there is reason to believe that the frequency of urine chemistry abnormalities may also differ in older adults. In this context, we characterized 24-hour urine findings in a large convenience sample of Medicare beneficiaries. METHODS: For our study, we analyzed urine chemistry data from Medicare beneficiaries 65 years of age and older with a diagnosis of USD, who had a 24-hour urine specimen processed by a large central laboratory in the U.S. between 2010 to 2019. For beneficiaries with multiple submitted specimens, we extracted analyte values from their first collection. Using laboratory reference ranges, we then determined whether a given beneficiary had evidence of hypercalciuria, hyperoxaluria, hypocitraturia, hyperuricosuria, or abnormal urine pH. Finally, we examined the frequency of multiple abnormalities (2, 3, and 4 or more) on a single collection. RESULTS: A total of 196,297 beneficiaries underwent 24-hour urine testing for USD. The tests increased from 24,744 in 2010 to 50,936 in 2019 (Figure 1). The sample adequacy, as determined by urine creatinine per body weight, was normally distributed (mean ± SD, 15.0 ± 4.5 mg/kg). Low urine volume was the most common abnormality (urine output less than 2 L/day in 61.9%), followed by hypocitraturia (43.8%), hyperoxaluria (34.2%), hypercalciuria (25%), and hyperuricosuria (17.3%). Twenty-five percent and 31.4% of beneficiaries had high and low urine pH, respectively. High urine sodium was observed in 17.3%. The percentages of beneficiaries with 2, 3, and 4 or more concurrent abnormalities were 33.9%, 35.2%, and 15.8%, respectively. CONCLUSIONS: Older adults with USD frequently have urine chemistry abnormalities, and often more than one abnormality is present. These data suggest that 24-hour urine testing in this population can help providers select interventions to help reduce future stone risk. Source of Funding: NIDDK R01DK121709 © 2022 by American Urological Association Education and Research, Inc.FiguresReferencesRelatedDetails Volume 207Issue Supplement 5May 2022Page: e438 Advertisement Copyright & Permissions© 2022 by American Urological Association Education and Research, Inc.MetricsAuthor Information Ryan Hsi More articles by this author Mary Oerline More articles by this author Joseph Crivelli More articles by this author Vahakn Shahinian More articles by this author John Hollingsworth More articles by this author Expand All Advertisement PDF DownloadLoading ...

Update on Uric Acid and the Kidney.

In this review, we report on new findings regarding associations of uric acid with kidney health. We discuss kidney stones, effects of uric acid in chronic kidney disease (CKD), and management of gout in CKD. Recent studies on neuroprotective effects of raising uric acid provide interesting data regarding nephrolithiasis. Elevated urate levels have been implicated in the progression of chronic kidney disease (CKD), but the results from PERL and CKD-FIX studies did not demonstrate that allopurinol slowed CKD progression. The SURE-PD3 sought to determine if increasing uric acid would slow the progression of Parkinson's disease. Results ultimately did not support this hypothesis, but high urinary uric acid levels caused uric acid stones, not calcium stones. Low urinary pH remains the key to the formation of uric acid stones. Thiazolidinediones improve insulin resistance, which is associated with an increase in urine pH. The most recent research has not supported the hypothesis that lowering serum uric acid levels will slow the progression of CKD or provide neuroprotection in Parkinson's disease. It is still unclear as to why uric acid stone formers have a high net acid excretion. The STOP-GOUT trial demonstrates that there was a lack of significant adverse events with higher urate-lowering dosages of allopurinol and febuxostat, despite patients' kidney function. This may push other studies to administer higher dosages per ACR guidelines. Future studies could then demonstrate decreased progression of CKD.

Defining 24-hour urine parameters and kidney stone risk of student athletes.

Dehydration is a risk factor for kidney stone formation. Studying populations that may experience dehydration without a known increased incidence of stone formation may help understand stone formation and prevention. High-caliber athletes represent such a population. We characterized the urinary environment of high-caliber athletes utilizing 24-hour urine collections with comparison to non-athlete controls. After Institutional Review Board (IRB) and National Collegiate Athletic Association (NCAA) compliance officer approval, 74 college-student athletes and 20 non-athletes were enrolled. Demographics, medical history, and sport of participation were recorded. Participants were asked to provide 24-hour urine collections as well as diet and activity logs at the time of urine collection. Standard stone risk parameters were assessed and compared to litholink reference standards. 34 athletes and 10 non-athletes provided at least one 24-hour urine specimen for evaluation. Athletes had a high prevalence of urinary risks for stone formation including low volume (median 1.46L), low citrate, high sodium, high calcium (females), and high uric acid (males). However, athletes also had a high prevalence of known stone-protective factors such as high urine magnesium. Athletes had a lower urine pH but high supersaturation of uric acid and calcium oxalate compared to non-athletes. Student athletes appear to have a high prevalence of urinary risk factors for stone formation such as dehydration, high calcium, high uric acid, high sodium, and low citrate. Overall stone risk in this population may be offset by increased levels of stone-protective factors such as magnesium. Further study of this population may help generate hypotheses for effective stone prevention strategies in the general population.

Association of acidic urine pH with impaired renal function in primary gout patients: a Chinese population-based cross-sectional study

BackgroundPatients with gout frequently have low urinary pH, which is associated with the nephrolithiasis. However, the specific distribution of urinary pH and potential relationship of acidic urine pH to broader manifestations of kidney disease in gout are still poorly understood.MethodsA 2016–2020 population-based cross-sectional study was conducted among 3565 gout patients in the dedicated gout clinic of the Affiliated Hospital of Qingdao University to investigate the association between low urinary pH and kidney disease. We studied patients that we defined to have “primary gout”, based on the absence of > stage 2 CKD. All subjects underwent 14 days of medication washout and 3-day standardized metabolic diet. We obtained general medical information, blood and urine biochemistries, and renal ultrasound examination on the day of the visit. The primary readouts were urine pH, eGFR, nephrolithiasis, renal cysts, microhematuria, and proteinuria. Patients were assigned into 5 subgroups (urine pH ≤5.0, 5.0 <pH≤ 5.5, 5.5 <pH< 6.2, 6.2 ≤pH≤ 6.9, and pH >6.9), aligning with the clinical significance of urine pH.ResultsOverall, the median urine pH and eGFR of all patients was 5.63 (IQR 5.37~6.09), and 98.32 (IQR 86.03~110.6), with acidic urine in 46.5% of patients. The prevalence of nephrolithiasis, microhematuria, and proteinuria were 16.9%, 49.5%, and 6.9%, respectively. By univariate analysis, eGFR was significantly associated with age, sex, duration of gout, tophus, body mass index, systolic blood pressure, diastolic blood pressure, fasting blood glucose, total cholesterol, serum utare, hypertension, diabetes, and urine pH. On multivariable analysis, eGFR was associated with age, sex, diastolic blood pressure, serum uric acid, hypertension, diabetes, and urine pH. Acidic urine pH, especially urine pH < 5.0, was significantly associated with the prevalence of kidney disease, including > stage 1 CKD, nephrolithiasis, kidney cyst, and microhematuria. Patients with 6.2 ≤ urine pH ≤ 6.9 and SU ≤ 480 μmol/L had the highest eGFR with the lowest prevalence of nephrolithiasis, microhematuria, and proteinuria.ConclusionsApproximately half of gout subjects had acidic urine pH. Urine pH < 5.0 was associated with significantly increased nephrolithiasis, renal cyst, microhematuria, and proteinuria. The results support prospective clinical investigation of urinary alkalinization in selected gout patients with acidic urine pH.

Acidic Urine Is Associated With Poor Prognosis of Upper Tract Urothelial Carcinoma.

PurposeTo assess the prognostic role of acidic urine (low urine pH) in upper tract urothelial cancer (UTUC).Materials and MethodsWe reviewed patients enrolled in Seoul National University Prospectively Enrolled Registry for Urothelial Cancer-Upper Tract Urothelial Cancer (SUPER-UC-UTUC) who underwent surgical resection from March 2016 to December 2020 in Seoul National University Hospital (SNUH). Patients with non-urothelial cancer or those who are in condition at end-stage renal disease were excluded. Acidic urine was defined as urine pH ≤ 5.5.ResultsA total of 293 patients with a mean age of 70.7 ± 9.5 years were enrolled in this study. Pre-operative laboratory results showed a mean estimated glomerular filtration rate (eGFR) of 64.1 ± 19.2 mL/min/1.73m2 and a mean urine pH of 5.86 ± 0.66. Patients were subdivided into low (pH ≤ 5.5) and high (pH > 5.5) urine pH for comparison. As a result, all variables were comparable except for the T stage, which was significantly higher in the low urine pH group (p = 0.017). Cox regression analysis was performed to assess the clinical impact of acidic urine on patient survival. Multivariate Cox regression analysis revealed that tumor multifocality (HR 2.07, p = 0.015), higher T stage (HR 1.54, p = 0.036), lymphovascular invasion (HR 1.69, p = 0.033), eGFR < 60 mL/min per 1.73 m2 (HR 1.56, p = 0.017), and acidic urine (HR 1.63, p < 0.01) independently decreased disease-free survival (DFS), while multifocality (HR 9.50, p < 0.01), higher T stage (HR 9.51, p = 0.001) and acidic urine (HR 10.36, p = 0.004) independently reduced the overall survival (OS).ConclusionsAcidic urine is independently associated with reduced DFS and OS in UTUC. Acidic urine contributing to acidic environment may promote acquisition of agressive behavior of UTUC.

Does Urinary pH and Diet Influence the Rate of Urinary Tract Infection Recurrence After Electrofulguration in Women With Antibiotic-Recalcitrant Recurrent Urinary Tract Infections?

ObjectivesTo assess if urine acidity may be preventative against urinary tract infection (UTIs) and affected by diet. Our goal was to evaluate the effect of urine pH on the rate of recurrent UTIs (RUTIs) after electrofulguration (EF) in 3 groups of women with different urine pH ranges as well as the relation between their diet composition and urine pH. MethodsIn a prior IRB-approved prospective study, women recorded urinary pH 4 times a day and diet for a week. Three urinary pH groups were identified: never below 6, never above 6, and above and below 6. In this study, a 3-day diet analysis involved categorizing different foods by acidity based on pH food charts and calculating amounts consumed using a nutritional analysis database. Rate of UTIs after EF and urine pH after consumption of acidic foods was compared between urine pH groups. Our hypothesis was that low urinary pH protects against RUTIs. ResultsOf 37/69 patients who underwent EF with long median follow-up duration (4-6 years), no difference was found among the groups for UTI frequency, rate, and culture characteristics. There was a no significant difference in the mean amount of acidic foods eaten and the urine pH after each meal as well as in total. ConclusionsDuring long-term follow-up, no association was found between urine pH groups and acidic food intake, and rates of UTIs after EF, possibly because of no link between urine pH and UTIs or EF already provokes an important reduction in rates of UTIs.

Can Routine Blood and Urine Parameters Reveal Clues to Detect Bladder Cancer? A Case-Control Study.

ObjectiveLimited attention has been paid to abnormal blood and urine test results for patients with bladder cancer. The present study aimed to identify whether blood and urine parameters are associated with bladder cancer.MethodsWe used a case–control design and matched each patient with bladder cancer with three healthy controls of the same age and sex. Univariate conditional logistic regression was used to calculate the crude and adjusted odds ratio (OR) and its 95% CI. Multivariate conditional logistic regression was performed for confounders adjustment, and Spearman’s correlation coefficient was used to assess the correlation between tumor T stages and urine parameters.ResultsPatients with bladder cancer (n = 360) and controls (n = 1050) were recruited. In the univariate conditional logistic analysis, higher urine pH was associated with a decreased risk of bladder cancer (OR = 0.67, 95% CI = 0.57–0.78), while higher values of urine protein (OR = 4.55, 95% CI = 3.36–6.15), urine glucose (OR = 1.56, 95% CI = 1.18–2.05), and urine occult blood (OR = 4.27, 95% CI = 3.44–5.29) were associated with an increased risk of bladder cancer. After adjustment for body mass index, fasting blood glucose, hypertension, red blood cells, white blood cells, lymphocytes, neutrophils, and platelets, significance still remained for urine pH (OR = 0.68, 95% CI = 0.53–0.88), urine protein (OR = 1.97, 95% CI = 1.21–3.19), urine glucose (OR = 2.61, 95% CI = 1.39–4.89), and urine occult blood (OR = 3.54, 95% CI = 2.73–4.58).ConclusionThis study indicated that lower urine pH and higher values of urine protein, urine glucose, and urine occult blood might be risk factors for bladder cancer.

The impact of stenting prior to oral chemolysis of upper urinary tract uric acid stones.

To evaluate the impact of ureteral stenting on the success rate of oral chemolysis in the management of suspected uric acid upper urinary tract (UUT) stones. Retrospective matched-pair analysis of 172 patients treated with oral chemolysis from 01/2010 to 12/2019. Patients with low density (upon non-contrast enhanced computer tomography [NCCT]), radiolucent (on plain radiography) urinary stones, a low urine pH (< 6) and/or history of uric acid urolithiasis were included. Potassium citrate and/or sodium bicarbonate were used for alkalization (target urine pH: 6.5-7.2). Patient 1:1 matching was performed for the presence of indwelling ureteral stent, stone diameter, stone density, and stone localization. Stone-free status was evaluated after 12weeks using NCCT. Multivariable logistic regression analysis was used to assess factors affecting the outcome. Mean patient age was 61years (73% males). Mean stone size was 12mm. Overall success rates after 12-weeks of chemolysis for stones at any localization in the UUT and ureteral stones were 60.5 and 77.3%, respectively. Smaller stone size (OR = 0.94; CI 0.888-0.992; p = 0.026) and lower pre-treatment urine pH (OR = 0.131; CI 0.023-0.737; p = 0.021) significantly increased the success of oral chemolysis. Ureteral stenting did not have any impact on the efficacy of oral chemolysis. Oral chemolysis is an effective treatment modality for patients with UUT stones suspected of uric acid content irrespective of ureteral stenting. Smaller stone diameter and lower urine pH at diagnosis increase its efficacy.

The Relationship between Modern Fad Diets and Kidney Stone Disease: A Systematic Review of Literature.

Objectives: Kidney stone disease (KSD) has a strong association with diet metabolic syndrome. This review aims at exploring the lithogenic risk posed by the current most popular diets. Our approach was to search for the effect of each diet type on the major urinary risk factors, to try to draw conclusions regarding the association of a specific diet type and KSD. Methods: This systematic review searched for the available literature exploring the association between the existing popular fad diets and KSD. Articles in English, French and Spanish were included, without restriction of the search period with the final search done in August 2021. Results: Total number of studies and studies for each diet type was as follows: 22 articles for the low carbohydrate diet, 20 articles for high protein diets, 26 articles for vegetarian and vegan diets. There exists a substantial variability in different low carbohydrate and high protein diets, and considerable overlap between modern popular fad diets. High carbohydrate intake might increase urine uric acid, calcium and oxalate levels. High protein diets increase urine calcium and uric acid and lower urine pH and citrate. Consumption of fruits and vegetables increases the urinary volume and urinary citrate. In vegan diets, sufficient daily calcium intake is important to avoid possible secondary hyperoxaluria. Conclusions: Few studies evaluated the direct relationship between modern fad diets and KSD. In general, the reduction of carbohydrate in the diet, and counterbalancing protein rich diets with sufficient intake of fruits and vegetables, seem to play a protective role against KSD formation. Maintaining sufficient calcium intake in vegan and vegetarian diets is important. Additional research is needed to directly evaluate the link between KSD and each diet type.

Effect of a very low negative dietary cation-anion difference (DCAD) diet on plasma and urine metabolomics of prepartum Holstein cows

The objectives of this cross-sectional, nonintervention, observational study were to compare urine and blood parameters between cows consuming a positive dietary cation-anion difference (DCAD) diet [early dry cows, DCAD + 250 mEq/kg of dry matter (DM), n = 15] with the same cows consuming a negative DCAD diet (−220 mEq/kg of DM) 10 d after moving them from the early dry to the prepartum group. The most remarkable finding was that cows consuming the anionic diet had very low urine pH and very low base excess in blood, suggestive of uncompensated metabolic acidosis. Importantly, the metabolomics data revealed that only urine concentrations of essential and aromatic amino acids were decreased, and that concentrations of total nonessential amino acids and glucogenic amino acids were increased in plasma and reciprocally decreased in urine, suggesting that the cows fed anionic salts were attempting to meet a high glucose demand by mobilizing gluconeogenic amino acid reserves. Notably, the dietary anionic salts exerted marked effects on glycerophospholipids, with a reduction in most phosphatidylcholine containing diacyl (PC aa) and acyl-alkyl (PC ae) moieties in plasma and urine. Further characterization of these metabolomic profiles may lead to the development of novel biomarkers to identify cows susceptible to metabolic acidosis and other metabolic diseases.

Urinary pH is an independent predictor of upper tract recurrence in non-muscle-invasive bladder cancer patients with a smoking history

Limited information is currently available on predictors of upper tract urothelial carcinoma (UTUC) recurrence in non-muscle-invasive bladder cancer (NMIBC) patients according to smoking history, although smoking probably contributes to urothelial carcinogenesis. Therefore, the present study aimed to identify independent predictors of UTUC recurrence in all patients and those with a smoking history. Our study population comprised 1190 NMIBC patients who underwent transurethral resection of bladder tumor. UTUC developed in 43 patients during the follow-up. A history of bacillus Calmette-Guérin (BCG) therapy was independently associated with a lower incidence of UTUC (HR = 0.43; P = 0.011). In a subgroup of NMIBC patients with a smoking history, concomitant carcinoma in situ (CIS) and a lower urinary pH (< 6) were independently associated with a higher incidence of UTUC recurrence (HR = 3.34, P = 0.006 and HR = 3.73, P = 0.008, respectively). Among patients with a longer smoking duration (≥ 20 years) or larger smoking intensity (≥ 20 cigarettes per day), those with lower urinary pH (< 6) had a significantly higher UTUC recurrence rate than their counterparts. These results suggest that BCG instillation may prevent UTUC recurrence in NMIBC patients, while a lower urinary pH and concomitant CIS increase the risk of UTUC recurrence in those with a smoking history.