Impact of body mass index on size and composition of urinary stones: a systematic review and meta-analysis

ABSTRACT Background Several studies have explored the impact of BMI on size and composition of urinary stones. Because there were controversies, a meta-analysis was necessary to be carried out to provide some evidence of the relationship of BMI and urolithiasis. Materials and Methods PubMed, Medline, Embase, Web of Science databases, and the Cochrane Library were searched up to August 12th 2022 for eligible studies. The urolithiasis patients were summarized into two groups: BMI < 25 and ≥ 25 kg/m2. Summary weighted mean difference (WMD), relative risk (RR) and 95% confidence intervals (CI) were calculated through random effects models in RevMan 5.4 software. Results A total of fifteen studies involving 13,233 patients were enrolled in this meta-analysis. There was no significant correlation of BMI and size of urinary stone (WMD -0.13mm, 95% CI [-0.98, 0.73], p = 0.77). Overweight and obesity increased the risk of uric acid stones in both genders and in different regions (RR=0.87, [95% CI] = 0.83, 0.91, p<0.00001). There was a higher risk of calcium oxalate stones formation in overweight and obesity group in total patients (RR=0.95, [95% CI] = 0.91, 0.98, p = 0.006). The relationship of BMI and calcium phosphate was not observed in this meta-analysis (RR=1.12, [95% CI] = 0.98, 1.26, p = 0.09). Sensitivity analysis was performed and indicated similar results. Conclusions The current evidence suggests a positive association between BMI and uric acid and calcium oxalate stones. It would be of great guiding significance to consider losing weight when treating and preventing urinary stones.

Impact of body mass index on size and composition of urinary stones: a systematic review and meta-analysis.

BACKGROUND: Several studies have explored the impact of BMI on size and composition of urinary stones. Because there were controversies, a meta-analysis was necessary to be carried out to provide some evidence of the relationship of BMI and urolithiasis. MATERIALS AND METHODS: PubMed, Medline, Embase, Web of Science databases, and the Cochrane Library were searched up to August 12th 2022 for eligible studies. The urolithiasis patients were summarized into two groups: BMI < 25 and ≥ 25 kg/m2. Summary weighted mean difference (WMD), relative risk (RR) and 95% confidence intervals (CI) were calculated through random effects models in RevMan 5.4 software. RESULTS: A total of fifteen studies involving 13,233 patients were enrolled in this meta-analysis. There was no significant correlation of BMI and size of urinary stone (WMD -0.13mm, 95% CI [-0.98, 0.73], p = 0.77). Overweight and obesity increased the risk of uric acid stones in both genders and in different regions (RR=0.87, [95% CI] = 0.83, 0.91, p<0.00001). There was a higher risk of calcium oxalate stones formation in overweight and obesity group in total patients (RR=0.95, [95% CI] = 0.91, 0.98, p = 0.006). The relationship of BMI and calcium phosphate was not observed in this meta-analysis (RR=1.12, [95% CI] = 0.98, 1.26, p = 0.09). Sensitivity analysis was performed and indicated similar results. CONCLUSIONS: The current evidence suggests a positive association between BMI and uric acid and calcium oxalate stones. It would be of great guiding significance to consider losing weight when treating and preventing urinary stones.

The influencing factors of infectious complications after percutaneous nephrolithotomy: a systematic review and meta-analysis.

Infection is the most common complications of percutaneous nephrolithotomy (PCNL) in treating urinary calculi. However, the risk factors for developing infectious complications after surgery have not been clarified, and the predictive value of some factors is controversial. This study aimed to assess the risk factors for postoperative infectious complications of PCNL. We performed a systematic search of PubMed, Web of Science, Cochrane Library, and EMBASE to obtain studies reporting risk factors for postoperative infection complications after PCNL. In this review, demographic factors, laboratory test factors, and perioperative factors were evaluated. The odds ratio (OR) or mean difference (MD) with a 95% confidence interval (CI) was calculated to assess the risk factors. A total of 18 studies were included, with a total of 7161 study patients with a mean age of 46.4 to 55.5 years and an incidence of infectious complications after PCNL ranging from 2.4% to 40.4%. Twelve factors were identified as independent risk factors for post-PCNL infection complications (P < 0.05), female (OR = 1.60, 95% CI 1.23-2.07), positive urine culture (UC) (OR = 3.16, 95% CI 2.11-4.74), positive renal pelvis urine culture (RPUC) (OR = 5.81, 95% CI 1.75-19.32), positive stone culture (SC) (OR = 5.11, 95% CI 1.46-17.89), positive urine leukocyte (OR = 3.61, 95% CI 2.45-5.34), infected stones (OR = 7.00, 95% CI 1.27-38.55), elevated blood leukocyte (MD = 0.71, 95% CI 0.31-1.10), elevated neutrophil-to-lymphocyte ratio (NLR) (MD = 0.55, 95% CI 0.43-0.66), preoperative stenting (OR = 1.55, 95% CI 1.10-2.20), multiple puncture access (OR = 2.58, 95% CI 1.75-3.82), prolonged operative time (MD = 10 20, 95% CI 4.80-15.60), and postoperative residual stone (OR = 1.56, 95% CI 1.24-1.98). Female, UC positivity, RPUC positivity, SC positivity, urine leukocyte positivity, infected stones, elevated peripheral blood leukocytes, elevated NLR, preoperative stent implantation, multiple puncture channels, prolonged operation time, and postoperative residual stones were identified as independent risk factors for infection complications after PCNL.

Comparison of postoperative outcomes of mini percutaneous nephrolithotomy and standard percutaneous nephrolithotomy: a meta-analysis.

Our study was aimed to evaluate the postoperative outcomes of Mini Percutaneous Nephrolithotomy (Mini-PCNL) and Standard Percutaneous Nephrolithotomy (Standard-PCNL) to determine the optimum option for patients with renal calculi. For publications published between January 2010 and April 2021, a comprehensive search of the PubMed, Cochrane Library, Web of Science, and EMBASE databases was done. The literatures were chosen based on the criteria for inclusion and exclusion. After the data were retrieved and the quality was assessed, the meta-analysis was performed using Review Manager Software (RevMan 5.4.1, Cochrane Collaboration, Oxford, UK). We selected 20 trials with a total of 4953 people out of 322 studies. There were 2567 patients treated with Mini-PCNL and 2386 patients treated with Standard-PCNL. Meta-analysis results showed no difference in stone-free rates (SFR, P = 0.93), fever (P = 0.83), and postoperative pain (VAS score) (P = 0.21) between Mini-PCNL and Standard-PCNL. Patients in the Mini-PCNL group experienced shorter hospital stay (P < 0.0001), less hemoglobin drop (P < 0.00001), less blood transfusion (P < 0.00001), higher postoperative tubeless (P = 0.0002), and fewer complications including bleeding (P = 0.01), perforation (P = 0.03), and leakage (P = 0.01). Compared with Standard-PCNL, operative time was longer in the Mini-PCNL group (P = 0.0005). Mini-PCNL had a shorter hospital stay, less hemoglobin drop, less blood transfusion, greater postoperative tubeless, fewer complications, and a longer operational time when compared to Standard-PCNL. SFR, fever, and postoperative pain were similar in both of them. Mini-PCNL may be a superior option for patients with proper size renal calculi.