Serum and urine uric acid level may have different predictive value for urinary stone composition: a retrospective cohort study of 718 patients in Chinese population

Distribution characteristics of staghorn calculi bacteria and metabolic differences in patients of different genders

OBJECTIVE

The objective of this study was to examine the distribution patterns of bacteria and to elucidate the distinctions in stone composition and metabolism.

METHODS

A review of 205 cases of staghorn stones treated at Beijing Tsinghua Changgung Hospital from January 2016 to June 2024 was conducted. Data on preoperative mid-course urine culture, blood biochemistry, 24-hour urine and postoperative stone composition were collected. Stones with > 50% mixed stone components or single components were defined as main stone components. According to the main components, patients with staghorn calculi were divided into infectious and non-infectious stone groups, and the distribution of bacteria among different stone groups was analyzed. The metabolic differences between patients with staghorn calculi of different genders were analyzed according to the results of blood biochemistry and 24-hour urine metabolism.

RESULTS

The study population consisted of 88 males and 117 females with an average age of 53 ± 12 years. The most common components were magnesium ammonium phosphate hexahydrate and carbonated apatite (40%). The prevalence of calcium oxalate stones (16.6%) and uric acid stones (9.3%) was significantly higher in males (P < 0.05), while infectious stones (42.9%) were more prevalent in females (P < 0.05). The detection rate of Proteus mirabilis was more prevalent in the infectious stone group (26.2%), whereas the detection rate of Ureaplasma urealyticum (9%) and Enterococcus faecalis (6.9%) were more prevalent in non-infectious stone group (P<0.05). The levels of serum uric acid, serum creatinine, urinary calcium, urinary sodium, urinary phosphorus, urinary chloride and urinary uric acid were found to be significantly higher in males than in females (P < 0.05).

CONCLUSION

The biochemical metabolism of patients with staghorn stones exhibits gender-specific differences, with a notable discrepancy in the distribution of bacteria. It is therefore necessary to refine the biochemical metabolic indicators and mid-stream urine culture tests.

A study of the difference in biochemical metabolism between patients with unilateral and bilateral upper urinary tract stones

Bilateral upper urinary tract stones are more likely to lead to impairment of renal function, but few biochemical metabolic studies of bilateral upper urinary tract stones have been reported. We collected clinical data from 555 patients with upper urinary tract stones admitted to Beijing Tsinghua Changgung Hospital from June 2020 to June 2024, and divided them into unilateral and bilateral stone groups by CT scans, analysed the metabolic differences between unilateral and bilateral stone groups by statistical methods, and used multifactorial logistic regression analysis to explore the risk factors that might affect the formation of bilateral stones. A total of 281 cases of unilateral and 274 cases of bilateral stones were identified. The proportion of male patients in the bilateral group was higher than that in the unilateral group (P < 0.05). The most prevalent major stone component was calcium oxalate monohydrate (48.1%), with a significantly higher prevalence of cystine stones observed in the bilateral stone group (1.8%) compared to the unilateral stone group (0.4%) (P < 0.05). Blood uric acid, blood BUN, blood creatinine, urine pH, and 24-hour urine output were higher in the bilateral stone group than in the unilateral group (P < 0.05). The most prevalent metabolic abnormality was low urine volume (45.7%). Bilateral stone group had higher proportion of patients with hyperuricemia (P < 0.05). The results of the multivariate logistic regression analysis showed that male gender (OR 1.489, 95% CI 1.028-2.157) and hyperuricemia (OR 1.662, 95% CI 1.113-2.482) were associated with an increased risk of bilateral stone formation (P < 0.05). There are significant differences in biochemical metabolism between unilateral and bilateral upper urinary tract stones. The most common metabolic abnormality in patients with urolithiasis is low urine output, and aggressive water intake is effective in preventing stone formation. For patients with hyperuricemia, a strict dietary regimen is imperative to mitigate the likelihood of bilateral stone formation.

A nomogram clinical prediction model for predicting urinary infection stones: development and validation in a retrospective study

PURPOSE

This study aimed to develop a nomogram prediction model to predict the exact probability of urinary infection stones before surgery in order to better deal with the clinical problems caused by infection stones and take effective treatment measures.

METHODS

We retrospectively collected the clinical data of 390 patients who were diagnosed with urinary calculi by imaging examination and underwent postoperative stone analysis between August 2018 and August 2023. The patients were randomly divided into training group (n = 312) and validation group (n = 78) using the "caret" R package. The clinical data of the patients were evaluated. Univariate and multivariate logistic regression analysis were used to screen out the independent influencing factors and construct a nomogram prediction model. The receiver operating characteristic curve (ROC), calibration curves, and decision curve analysis (DCA) and clinical impact curves were used to evaluate the discrimination, accuracy, and clinical application efficacy of the prediction model.

RESULTS

Gender, recurrence stones, blood uric acid value, urine pH, and urine bacterial culture (P < 0.05) were independent predictors of infection stones, and a nomogram prediction model ( https://zhaoyshenjh.shinyapps.io/DynNomInfectionStone/ ) was constructed using these five parameters. The area under the ROC curve of the training group was 0.901, 95% confidence interval (CI) (0.865-0.936), and the area under the ROC curve of the validation group was 0.960, 95% CI (0.921-0.998). The results of the calibration curve for the training group showed a mean absolute error of 0.015 and the Hosmer-Lemeshow test P > 0.05. DCA and clinical impact curves showed that when the threshold probability value of the model was between 0.01 and 0.85, it had the maximum net clinical benefit.

CONCLUSIONS

The nomogram developed in this study has good clinical predictive value and clinical application efficiency can help with risk assessment and decision-making for infection stones in diagnosing and treating urolithiasis.

Uric acid en route to gout

Gout and hyperuricemia (HU) have generated immense attention due to increased prevalence. Gout is a multifactorial metabolic and inflammatory disease that occurs when increased uric acid (UA) induce HU resulting in monosodium urate (MSU) crystal deposition in joints. However, gout pathogenesis does not always involve these events and HU does not always cause a gout flare. Treatment with UA-lowering therapeutics may not prevent or reduce the incidence of gout flare or gout-associated comorbidities. UA exhibits both pro- and anti-inflammation functions in gout pathogenesis. HU and gout share mechanistic and metabolic connections at a systematic level, as shown by studies on associated comorbidities. Recent studies on the interplay between UA, HU, MSU and gout as well as the development of HU and gout in association with metabolic syndromes, non-alcoholic fatty liver disease (NAFLD), and cardiovascular, renal and cerebrovascular diseases are discussed. This review examines current and potential therapeutic regimens and illuminates the journey from disrupted UA to gout.