24-h urine metabolic profile: is it necessary in all kidney stone formers?

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).

Serum and 24-hour urinary tests cost-effectiveness in stone formers

OBJECTIVE

To assess the routine serum and 24-hour urine tests proficiency in diagnosing the baseline metabolic abnormality of kidney stone formers.

METHODS

This study analyzes the routine serum and 24-hour urine tests proficiency in diagnosing the baseline metabolic abnormality of kidney stone formers. The sensitivity and specificity, false positive, and negative results of the tests are extracted from diagnostic kits used in the laboratories of the target community. To accurately infer the results, a simulation based on 1000 people was used through 22 standard laboratory tests (Additional File 2), including calcium, oxalate, phosphate, uric acid, sulfate, potassium, sodium, citrate, and magnesium in 24-hour urine; and calcium, creatinine, Vit D, uric acid, and intact parathyroid hormone (PTH) in serum. The incremental cost-effectiveness ratio (ICER) was calculated and compared for each diagnostic test versus other diagnostic tests according to the incremental cost required for correct diagnoses of stone causes.

RESULTS

Urinary uric acid, citrate, and serum potassium constitute the cost-effectiveness boundary curve in this study. This means that other diagnostic tests are not cost-effective compared to these three tests in terms of indexing at least one item of cost and effectiveness. The ICER index for each correct diagnosis with the urinary uric acid test was $ 1.25 per diagnosis, the most cost-effective test compared to serum potassium and urinary citrate.

CONCLUSION

The simplified blood and 24-hour urine metabolic evaluation, including urinary uric acid, citrate, and serum potassium, constitute the cost-effectiveness boundary curve. The most cost-effective test was urinary uric acid measurement.

Development and validation of a nomogram for risk prediction of nephrolithiasis recurrence in patients with primary hyperparathyroidism

BACKGROUND

Nephrolithiasis is a common complication of primary hyperparathyroidism (PHPT), and the recurrence of nephrolithiasis in patients with PHPT is also an urgent concern. What is worse, there is a scarcity of recommended evaluation to predict the risk of nephrolithiasis recurrence in patients with PHPT. This study was aimed to develop and validate a nomogram to facilitate risk assessment in patients with PHPT.

METHODS

A total of 197 patients with PHPT were retrospectively included in this study from September 2016 to August 2021. Patients' demographic data, blood test parameters, urinalysis, stone parameters, and surgical intervention were collected. Extracted variables were submitted to a least absolute shrinkage and selection operator (LASSO) regression model. A nomogram was built and validated according to the area under the curve (AUC) value, calibration curve, and decision curve analysis.

RESULTS

According to the LASSO regression and logistic regression analyses, five predictors were derived from 22 variables: creatinine, uric acid, bilateral stone, multiplicity, and surgery. The AUC and concordance index of the training cohort and validation cohort were 0.829 and 0.856, and 0.827 and 0.877, respectively. The calibration curve analysis and the decision curve analysis showed that the nomogram had an adequate prediction accuracy.

CONCLUSION

We built a useful nomogram model to predict the risk of nephrolithiasis recurrence in patients with PHPT. This would assist clinicians to provide appropriate advices and managements for these patients.

The new patterns of nephrolithiasis: What has been changing in the last millennium?

Nephrolithiasis has been increasing over the last millennium. Although early epidemiologic studies have shown that kidney stones were two to three times more frequent in males than in females, recent reports have suggested that this rate is decreasing. In parallel a dramatic increase of nephrolithiasis has also been observed among children and adolescents. Furthermore, epidemiologic studies have shown a strong association between metabolic syndrome (Mets) traits and kidney stone disease. Patients with hypertension have a higher risk of stone formation and stone formers are predisposed to develop hypertension compared to the general population. An incidence of nephrolithiasis greater than 75% has been shown in overweight and obese patients compared to those of normal weight. It has also been reported that a previous diagnosis of diabetes mellitus increases the risk of future nephrolithiasis. Additionally, an association between metabolic syndrome and uric acid stone formation has been clearly recognized. Furthermore, 24-h urinary metabolic abnormalities have been decreasing among patients with nephrolithiasis over the last decades. Finally, nephrolithiasis could cause chronic kidney disease (CKD) and end stage renal disease (ESRD), especially in women and overweight patients. According to these observations, a better understanding of these new features among stone former patients may be required. Hence, the recognition and the correction of metabolic disorders could help not only to reduce the primary disease, but also stone recurrence.

The lipid peroxidation in patients with nephrolithiasis before and after extracorporeal shock wave lithotripsy

AIM

To evaluate the level of lipid peroxidation in patients with nephrolithiasis before and after extracorporeal shock wave lithotripsy (ESWL).

MATERIALS & METHODS

Isoprostane concentration (8-isoPGF_2α) was measured in urine, and thiobarbituric acid reactive substance production in serum and erythrocytes. In addition, the concentrations of selected compounds (uric acid, glucose and creatinine) were measured in serum.

RESULTS

The patients (before and after ESWL) demonstrated significantly higher levels of two different biomarkers of lipid peroxidation compared with the control group. A correlation was identified between increased amounts of uric acid and biomarkers of lipid peroxidation in patients with nephrolithiasis, both before and after ESWL.

CONCLUSION

Uric acid may be associated with lipid peroxidation in patients with nephrolithiasis.