Methodological Variations in 24-Hour Urine Collection for Nephrolithiasis: A Systematic Review of Reporting Practices...

Area of Science:

• Nephrology
• Urology
• Clinical Research Methodology

Background:

• 24-hour urine collection is crucial for metabolic evaluation and nephrolithiasis prevention.
• Current research faces limitations due to inconsistent reporting and analysis of 24-hour urine parameters.
• These inconsistencies impact the reliability, reproducibility, and clinical utility of findings.

Purpose of the Study:

• To review and evaluate the reporting, analysis, and interpretation methods of 24-hour urine parameters in nephrolithiasis research.
• To identify inconsistencies and variability in data handling across published studies.
• To provide recommendations for improving research rigor and reproducibility.

Main Methods:

• Methodological review of 264 studies involving 450,624 patients with nephrolithiasis.
• Data extraction focused on urine collection protocols, parameter reporting, units, statistical methods, and missing data handling.
• Analysis of reporting formats, common units, statistical tests, and missing data imputation strategies.

Main Results:

• Significant variability observed in reporting formats, units (e.g., mg/day, mmol/day), and statistical analyses (t-tests, chi-square, limited multivariate regression).
• Calcium, citrate, oxalate, and uric acid were frequently reported, but supersaturation indices were less common.
• Complete case analysis was the predominant method for handling missing data (71.2%), with many studies not reporting their approach.
• Few studies reported power calculations (6.8%) or provided reference ranges (40.9%).

Conclusions:

• Substantial heterogeneity exists in the reporting and analysis of 24-hour urine data in nephrolithiasis research.
• This variability compromises evidence synthesis, external validation, and the application of advanced analytical tools like AI.
• A standardized reporting checklist is proposed to enhance the rigor, reproducibility, and clinical relevance of future studies.