Differences in 24-h urine composition between nephrolithiasis patients with and without diabetes mellitus

Incidence of metabolic syndrome in patients with unilateral or bilateral staghorn renal stones and its impact on percutaneous nephrolithotomy outcomes

BACKGROUND

To evaluate the incidence of metabolic syndrome (MetS) in patients with unilateral and bilateral staghorn calculi (SC) and evaluate the impact on the outcome of percutaneous nephrolithotomy (PCNL).

METHODS

The clinical data of patients who underwent PCNL for the treatment of SC between 2019 and 2022 were retrospectively reviewed. SC was divided into unilateral and bilateral. The incidence of MetS was compared between the patients with unilateral SC and the patients with bilateral SC, and the impact on the outcome of PCNL was assessed.

RESULTS

A total of 1778 patients underwent PCNL between 2019 and 2022. After screening computed tomography, 379 patients were confirmed to have SC, finally, leaving 310 patients with follow-up and complete data to be included in the study. Eighty-four had bilateral SC and 226 had unilateral SC. The patients with bilateral SC had a significantly higher body mass index and higher rates of complete staghorn stones and metabolic syndrome. Higher body mass index, hypertension, diabetes mellitus, hyperlipidaemia, and MetS were present in 62.58%, 44.84%, 21.94%, 60.65% and 27.42% of all patients, respectively. The number of MetS components remained significantly associated with bilateral SC. Specifically, when the number of MetS components increases from 0 to 3-4, the likelihood of developing bilateral staghorn calculi increases by 21.967 times. Eighty-five patients with MetS( +) had a higher rate of overall complications (number (N)(%), 29 (34.12) vs.33 (14.46), P < 0.001) and a comparable stone-free rate to 225 MetS(-) patients. Multivariable analysis confirmed that hyperlipidaemia (P = 0.044, odds ratio [OR] = 1.991, 95% confidence interval [CI] 1.020-3.888) and MetS (P = 0.005, OR = 2.427, 95% CI 1.316-4.477) were independent risk factors for overall complications.

CONCLUSIONS

MetS is correlated with the formation of bilateral SC and is the main predictor for complications of PCNL especially for low-grade complications (I-II).

Diabetes Mellitus Promotes Smooth Muscle Cell Proliferation in Mouse Ureteral Tissue through the P-ERK/P-JNK/VEGF/PKC Signaling Pathway

Background and objectives: The aim of our study was to evaluate the role of diabetes mellitus (DM) as a significant factor affecting spontaneous stone expulsion, as suggested by previous research. Materials and methods: We investigated the influence of DM on the ureter using a murine model. The mouse-model arm of this study used 20 15 -week-old mice, including 10 normal (control) mice and 10 DM mice. We measured the proximal, middle and distal ureteral smooth muscle thickness in each mouse and the differences among ureteral sections were analyzed. Mouse ureteral specimens were also analyzed via western blotting to detect relative protein expression of phosphor–extracellular signal regulated kinases (P–ERK), phosphor–C–Jun N–terminal kinase (P–JNK), vascular endothelial growth factor (VEGF), and protein kinase C (PKC), which are representative factors involved in cell regulation. Results: We observed significant hyperproliferation of ureteral smooth muscle in DM mice compared to normal mice, which may provoke reduced peristalsis. The ureteral smooth muscle of DM mice was significantly thicker than that of normal mice in all ureteral tissues: proximal (p = 0.040), mid (p = 0.010), and distal (p = 0.028). The relative protein expression of P-ERK (p = 0.005) and P–JNK (p = 0.001) was higher in the diabetic group compared to the normal group. Additionally, protein expression of VEGF (p = 0.002) and PKC (p = 0.001) were remarkably up-regulated in DM mice. Conclusions: Hyperproliferation of ureteral smooth muscle was observed in DM mice, but not in normal mice. The pathways mediated by P–ERK, P–JNK, VEGF, and PKC may play an important role in pathological ureteral conditions.

Impact of age and renal function on urine chemistry in patients with calcium oxalate kidney stones

Nephrolithiasis is associated with an increased risk of chronic kidney disease, and its incidence varies with age. However, little is known on the combined impact of aging and declining renal function on urinary risk factors for calcium oxalate stone formation. A retrospective analysis was performed on 24-h urine collections from 993 calcium oxalate stone-forming patients. We first tested for interactions between age and creatinine clearance on various urinary determinants of calcium oxalate nephrolithiasis, and then examined their separate and combined effects in univariable and multivariable analyses adjusting for demographic and biochemical covariates. We identified significant interactions between age and creatinine clearance in predicting 24-h urine pH, calcium, and citrate. In view of the small number of stone formers with low creatinine clearance, we limited further regression analyses to patients with creatinine clearance ≥ 60 mL/min. In multivariable analyses, urine citrate, oxalate, and total volume were positively correlated with age, whereas urine pH, citrate, calcium, oxalate, total volume, and RSR of calcium oxalate all significantly decreased with lower creatinine clearance. A decrease in creatinine clearance from 120 to 60 mL/min was associated with clinically significant decreases in the daily excretion rate of citrate (by 188 mg/day), calcium (by 33 mg/day), and oxalate (by 4 mg/day), and in RSR calcium oxalate (by 1.84). Age and creatinine clearance are significant and independent predictors of several urinary determinants of calcium oxalate nephrolithiasis. The impacts of aging and declining renal function should be considered during the management of calcium oxalate stone-forming patients.

Proton-pump inhibitors associated with decreased urinary citrate excretion

INTRODUCTION

Proton-pump inhibitors (PPIs) may increase the risk of kidney stone formation, but the mechanism has not been elucidated. There is a paucity of literature evaluating the effects of PPIs on urinary metabolites and urine pH.

METHODS

We performed a retrospective review of nephrolithiasis patients treated at our institution and compared patients who were taking PPIs to those who were not at the time of their 24-h urine collections. Hierarchical multivariate linear regression was used to evaluate the independent relationship between PPI use and urinary mineral composition.

RESULTS

We identified 301 consecutive patients, 88 (29%) of whom were taking PPIs at the time of their 24-h urine collections. Patients taking PPIs were older and more likely to have medical comorbidities associated with metabolic syndrome such as hypertension, diabetes, and dyslipidemia (p < 0.01). Controlling for these factors, patients taking PPIs were found to have 12% lower 24-h urine citrate excretion (β =  - 0.12, ΔF = 4.24, p = 0.04). There were no other differences in urinary mineral composition between the groups.

CONCLUSION

Our findings suggest that patients who take PPIs regularly may be at risk for decreased urinary citrate excretion. The consequent decrease in urinary citrate may become clinically significant for patients with other predisposing factors for hypocitraturia.

Diabetes Mellitus Might Not Be Associated with Any Stone Component in a Local District

BACKGROUND

Type II diabetes mellitus (DM) is a risk factor for urinary stones, but the pathogenesis remains unclear. The aim of our study was to present the distribution of stone components between DM and no DM group from a local stone center in China and to help the prevention department in decision-making.

METHODS

We reviewed the records of patients with upper urinary stones attending our hospital from January 2015 to September 2018. The patients with complete information were divided into 2 groups: type II DM group (DM group) and without DM group (no DM group). The distribution of stone components was analyzed.

RESULTS

Two hundred twenty-two patients were complicated with DM, whereas 1,894 (89%) were not. Significant difference was found in the distribution of hypertension and BMI (p = 0, p = 0, respectively). Distribution of sex, age, and stone components did not differ between the 2 groups. By the binary logistic analysis, increasing age and sex seemed to be the main risk factors influencing the stone components. Only the calcium stone seemed to be free of the -impact from age and sex. Occurrence of hypertension is a single risk factor for calcium stone from our analysis. Presence of diabetes and increasing BMI was not found to be significantly associated with the risk for any stone component.

CONCLUSIONS

In a local district, DM might not be the main factor associated with an increased risk for uric acid stone formation or any stone component. We should also consider the local characteristics of the stone distribution.

The association of calcium oxalate deposition in kidney allografts with graft and patient survival

BACKGROUND

Whether calcium oxalate (CaOx) deposition in kidney allografts following transplantation (Tx) adversely affects patient outcomes is uncertain, as are its associated risk factors.

METHODS

We performed a retrospective cohort study of patients who had kidney allograft biopsies performed within 3 months of Tx at Brigham and Women's Hospital and examined the association of CaOx deposition with the composite outcome of death or graft failure within 5 years.

RESULTS

Biopsies from 67 of 346 patients (19.4%) had CaOx deposition. In a multivariable logistic regression model, higher serum creatinine [odds ratio (OR) = 1.28 per mg/dL, 95% confidence interval (CI) 1.15-1.43], longer time on dialysis (OR = 1.11 per additional year, 95% CI 1.01-1.23) and diabetes (OR = 2.26, 95% CI 1.09-4.66) were found to be independently associated with CaOx deposition. CaOx deposition was strongly associated with delayed graft function (DGF; OR = 11.31, 95% CI 5.97-21.40), and with increased hazard of the composite outcome after adjusting for black recipient race, donor type, time on dialysis before Tx, diabetes and borderline or acute rejection (hazard ratio 1.90, 95% CI 1.13-3.20).

CONCLUSIONS

CaOx deposition is common in allografts with poor function and portends worse outcomes up to 5 years after Tx. The extent to which CaOx deposition may contribute to versus result from DGF, however, cannot be determined based on our retrospective and observational data. Future studies should examine whether reducing plasma and urine oxalate prevents CaOx deposition in the newly transplanted kidney and whether this has an effect on clinical outcomes.

Predictive Factors for Kidney Stone Recurrence in Type 2 Diabetes Mellitus

OBJECTIVE

To determine the predictive factors for kidney stone recurrence in type 2 diabetic patients.

METHODS

A retrospective cohort study was conducted from 2013 to 2019 by using the database of diabetic patients diagnosed with kidney stone disease. The patients were divided into 2 groups according to stone disease status: recurrent stone and nonrecurrent stone. Baseline characteristics were compared and logistic regression was done to assess which variables could predict a stone recurrence.

RESULTS

There were 1617 type 2 diabetic patients with kidney stone disease, 1244 (77%) did not have a stone recurrence and 373 (23%) had a stone recurrence. Of these patients with recurrent stone, 40% had asymptomatic stones, 43% visited emergency department, and 45% required a surgical intervention. Median time to recurrence was 64 months. Multivariable analysis revealed that body mass index (odds ratios [OR] 1.032, 95% confidence interval [CI] 1.016-1.047), urine pH (OR 0.500, CI 0.043-0.581), HbA1c (OR 1.186, CI 1.012-1.277), diabetic neuropathy (OR 1.839, CI 1.413-2.392), diabetic retinopathy (OR 1.690, CI 1.122-2.546), insulin as well as potassium citrate therapy (OR 0.611, CI 0.426-0.87), and stone with calcium oxalate and uric acid composition (OR 1.955, CI 1.420-2.691 and OR 2.221, CI 1.249-3.949, respectively) are significant predictors for stone recurrence.

CONCLUSION

The severity of diabetes and stone composition are strong predictors for stone recurrence in type 2 diabetic patients, while HbA1c and urine pH are important modifiable factors.

Association between hypertension and 24-h urine composition in adults without urolithiasis in China

PURPOSE

To explore the association between hypertension and 24-h urine composition in adults without urolithiasis in China.

MATERIALS AND METHODS

Blood test and 24-h urine analysis were performed on 958 non-stone formers in six cities to select eligible participants. Eligible participants were divided into hypertension group and non-hypertension group according to WHO guidelines. The 24-h urine compositions between two groups were compared using univariate and multivariate logistic regressions.

RESULTS

A total of 584 adults without urolithiasis were included in this analysis. Compared with non-hypertension group, hypertension group had significantly older age, higher BMI, higher prevalence of diabetes mellitus and higher levels of total cholesterol and LDL, but lower eCCr value, lower levels of serum creatinine and serum sodium (all P value < 0.05). In univariable comparisons, hypertension patients had significantly higher level of urine potassium (mean difference [MD] = - 3.89 mmol, 95% confidence interval [CI] - 7.37 to - 0.42, P = 0.014) but lower levels of urine creatinine (MD = 0.80 mmol, 95% CI 0.21-1.39, P = 0.004) and pH (MD = 0.12, 95% CI - 0.01 to 0.25, P = 0.033) than non-hypertension adults. However, no significant difference was found in all 24-h urinary components between two groups (all P value > 0.05) in multivariate Logistic regression analyses.

CONCLUSIONS

Our study demonstrated that hypertension did not independently influence the 24-h urine composition in adults without urolithiasis in China; however, we cannot make such an arbitrary conclusion that hypertension was not a risk factor for urolithiasis.

Mechanisms for falling urine pH with age in stone formers

One of the main functions of the kidney is to excrete an acid load derived from both dietary and endogenous sources, thus maintaining the pH of other fluids in the body. Urine pH is also of particular interest in stone formers, since it determines the presence of either calcium phosphate or uric acid content in stones. Others have noted in epidemiological studies a rise in incidence of low pH-dependent uric acid stones with age, coinciding with a decrease in the incidence of high pH-dependent phosphate stones. Taken together, these trends are suggestive of a longitudinal decline in urine pH in stone-forming patients, and, if true, this could explain the observed trends in stone incidence. We studied 7,891 stone formers, all of whom collected a 24-h urine sample and matching serum. Multivariate modeling revealed that urine pH did indeed fall with age and particularly between the ages of 20 and 50 yr old in both men and women. We sought to explain this trend through the inclusion of traditionally understood determinants of urine pH such as urinary buffers, estimates of glomerular filtration, and dietary acid load, but these, taken together, accounted for but a small fraction of the pH fall. Gastrointestinal anion absorption was the strongest predictor of urine pH in all age groups, as we have previously reported in middle-aged normal men and women. However, we found that, despite a decreasing urine pH, gastrointestinal anion absorption increased monotonically with age. In fact, after adjustment for gastrointestinal anion absorption, urine pH declined more markedly, suggesting that bicarbonate-producing anion absorption is regulated in a manner that offsets the decline of urine pH.

Nephrolithiasis against type 2 diabetes mellitus: on the effect of hypoglycemic therapy on lithogenesis

Aim. To study the effects of oral hypoglycemic agents that can affect the probability of recurrence of nephrolithiasis. Materials and methods. The article is based on the results of examination and treatment of 315 patients suffering from recurrent nephrolithiasis and medically compensated type 2 diabetes mellitus treated at the N.A. Lopatkin Institute of Urology and Interventional Radiology - the branch of the SMRC of Radiology, Ministry of Health of Russia and D.D. Pletnev City Hospital Moscow Healthcare Department in 2012-2017. The patients were divided into three groups according to the applied tool antidiabetic: metformin, glibenclamide, canagliflozin. The control group consisted of patients receiving insulin therapy. Results and discussion. The propensity of Metformin to reduce the pH of urine, which has a negative impact in the conditions of urate nephrolithiasis, which is most common in the population of patients with type 2 diabetes mellitus. Glibenclamide, on the contrary, somewhat latches urine. But changes in the reaction of urine under the influence of the drug do not go beyond normal values and are not clinically significant. Canagliflozin increases diuresis due to medication induced glycosuria and stimulates renal excretion of uric acid and its salts. However canagliflozin does not cause significant shifts in the pH of urine that may somewhat negates the increased risk of recurrence of urate stone formation in the background of the uricosuric effect of the drug. Conclusion. Drug therapy of type 2 diabetes mellitus significantly affects the properties of urine from patients with nephrolithiasis.

Successful Diabetic Control as Measured by Hemoglobin A1c Is Associated with Lower Urine Risk Factors for Uric Acid Calculi

INTRODUCTION AND OBJECTIVES

To examine the association of glycemic control, including strict glycemic control, with 24-hour urine risk factors for uric acid and calcium calculi.

MATERIALS AND METHODS

With institutional review board (IRB) approval, we identified 183 stone formers (SFs) with 459 twenty-four-hour urine collections. Hemoglobin A1c (HgbA1c) measures were obtained within 3 months of the urine collection. Collections were categorized into normoglycemic (NG, HgbA1c < 6.5) and hyperglycemic (HG, HgbA1c ≥ 6.5) cohorts; 24-hour urine parameters were compared. The NG cohort was further divided into patients with and without a history of diabetes mellitus (DM) type 2. Variables were analyzed using chi-square, Welch's t-test and multivariate linear regression to adjust for clustering, body mass index (BMI), age, gender, thiazide use, and potassium citrate use.

RESULTS

Patients in the HG group were older with higher BMI. Multivariate analysis of the total study population revealed that hyperglycemia correlated with lower pH, higher uric acid relative saturation (RS), lower brushite RS, and higher citrate. NG SFs with and without a history of DM had similar risk factors for uric acid stone formation. Among NG SFs, those with DM had higher urine calcium and calcium oxalate RS than those without DM. However, this difference may be related to other factors since neither parameter correlated with DM on multivariate regression (p > 0.05).

CONCLUSIONS

Successful glycemic control may be associated with reduced urinary risk factors for uric acid stone formation. Patients with well-controlled DM had equivalent risk factors to those without DM. Glycemic control should be considered a target of the multidisciplinary medical management of stone disease.

The influence of metabolic syndrome and its components on the development of nephrolithiasis

The prevalence of kidney stone disease is increasing, afflicting 7%–11% of the United States population. Multiple systemic conditions, including obesity and diabetes, are also on the rise. Further, the literature has demonstrated a strong association between metabolic syndrome, its components, and kidney stone disease. In this article, we aim to review the associations of metabolic syndrome and nephrolithiasis, discussing the pathophysiology, urinary parameters, and clinical presentations. With this knowledge, urologists will have a more comprehensive understanding of this complex population of metabolic stone formers enabling improved patient management and treatment of stone disease.

Nephrolithiasis: A complication of pediatric diabetic ketoacidosis

OBJECTIVE

To determine the frequency of nephrolithiasis as a complication of diabetic ketoacidosis (DKA) in pediatrics.

METHODS

We performed a retrospective chart review of patients with DKA admitted to a pediatric hospital between January 2009 and July 2016. We identified patients with nephrolithiasis during admission for DKA.

RESULTS

We identified 395 episodes of DKA over 7.5 years. Nephrolithiasis developed as a complication of DKA in 3 of those admissions (0.8%). All three patients with nephrolithiasis were males with new onset type 1 diabetes, aged 11 to 16.5 years. They all developed symptoms of nephrolithiasis after transition to subcutaneous insulin. One patient had subsequent worsening acidosis that required an additional 24 hours of IV insulin administration.

CONCLUSIONS

Nephrolithiasis is a rare complication of pediatric DKA, and should be considered in children with DKA who develop hematuria, flank pain, or suprapubic pain. Nephrolithiasis can increase insulin resistance due to increased pain and inflammation, so these patients should be monitored closely for recurrence of DKA. As patients with diabetes have increased risk of chronic kidney disease and nephrolithiasis can cause kidney injury, risk factors for nephrolithiasis should be identified and addressed to avoid subsequent kidney damage.

The impact of body mass index on quantitative 24-h urine chemistries in stone forming patients: a systematic review and meta-analysis

To study the impact of body mass index (BMI) on quantitative 24-h urine chemistries in stone forming patients and to explore how overweight and obesity contribute to urolithiasis. A systematic search of PubMed, EMBASE, Cochrane Library, and Web of Science was performed in July 2017 and updated in October 2017 to detect relevant studies. After that, we screened all the relevant articles in accordance with the predetermined inclusion and exclusion criteria. Data of eligible studies were extracted, and then, a meta-analysis was conducted via RevMan 5.3 software. Nine studies, involving 5965 stone forming patients who underwent 24-h urine collection for chemistry analysis, were included in our analysis. BMI was used to clarify the body size. BMI ≥ 25 kg/m² group, including overweight and obesity patients, erected more calcium (WMD 34.44 mg; 95% CI 11.33-57.55; p = 0.003), oxalate (WMD 3.44 mg; 95% CI 1.40-5.49; p = 0.001), urate (WMD 97.71 mg; 95% CI 63.05-132.38; p < 0.00001), and sodium (WMD 26.64 mg; 95% CI 18.23-35.05; p < 0.00001) in 24 h than BMI < 25 kg/m² group. However, the BMI < 25 kg/m² group showed higher pH of urine (WMD 0.12; 95% CI 0.04-0.20; p = 0.004). There was no significant difference in 24-h urine volume (WMD - 29.30 ml; 95% CI - 122.03 to - 63.42; p = 0.54), citrate (WMD - 34.03 mg; 95% CI - 72.88 to 4.82; p = 0.09), magnesium (WMD - 4.50 mg; 95% CI - 10.48 to 1.48; p = 0.14), phosphate (WMD - 89.38 mg; 95% CI - 219.23 to 40.47; p = 0.18), and creatinine (WMD - 191.98 mg; 95% CI - 395.35 to 11.38; p = 0.06) between the two groups. All the results kept the same tendency when gender was taken in consideration. Sensitivity analysis generated similar results. The current evidence suggested that patients with BMI ≥ 25 kg/m² erected more promotions but not inhibitors of urolithiasis than those with BMI < 25 kg/m², which increased the risk of urolithiasis in overweight and obesity individuals.

Diabetes Mellitus Type 2: A Driving Force for Urological Complications

Type 2 diabetes mellitus (T2DM) is a growing epidemic associated with many adverse complications. Urological complications of diabetes mellitus in men are gaining recognition. Previously unknown associations between T2DM and risk for prostate cancer, bladder cancer, renal cell carcinomas, urinary tract infections, nephrolithiasis, penile lesions, androgen deficiency, and erectile dysfunction have been discovered. Significantly, metformin could play a role in the management of urological malignancies, and therapies used for management of these cancers could in return lead to increased risk for diabetes. In this review, we aim to bridge the gap between T2DM and urological complications by discussing the latest findings in these fields, with the ultimate goal being improved patient care on both fronts.

Difference in 24-Hour Urine Composition between Diabetic and Non-Diabetic Adults without Nephrolithiasis

Background

Diabetic patients are more likely to develop kidney stones than the general population. The underlying mechanisms for this disparity remain to be elucidated. Little is known about the relationship between urine composition and diabetes mellitus in non-stone-forming individuals. We sought to examine the differences in the 24-hour (24-h) urine composition between diabetic and non-diabetic adults who were not stone formers.

Methods

A convenience sample of 538 individuals without a history of nephrolithiasis, gout, hyperparathyroidism, or gastroenteric diseases participated in this study. The 24-h urine profiles of 115 diabetic adults were compared with those of 423 non-diabetic adults. Diabetes was defined by self-reported physician diagnosis or medication use. All participants were non-stone formers confirmed by urinary tract ultrasonography. Participants provided a fasting blood sample and a single 24-h urine collection for stone risk analysis. Student’s t-test was used to compare mean urinary values. Linear regression models were adjusted for age, gender, body mass index, hypertension, fasting serum glucose, serum total cholesterol, estimated creatinine clearance rate and urinary factors.

Results

Univariable analysis showed that the diabetic participants had significantly higher 24-h urine volumes and lower urine calcium and magnesium excretions than non-diabetic participants (all P < 0.05). After multivariate adjustment, no significant differences in 24-h urine composition were observed between diabetic and non-diabetic participants except for a slightly increased 24-h urine volume in diabetic participants (all P > 0.05). The main limitation of this study is that the convenience samples and self-reported data may have been sources of bias.

Conclusion

Our data showed that there were no differences in 24-h urine composition between diabetic and non-diabetic adults who are not stone formers. The reason for it might be the improved glycemic control in diabetic individuals in our study. Therefore, a tighter glycemic control might reduce stone formation in diabetic adults.