The Effect of Metabolic Syndrome on the Success and Complications of Percutaneous Nephrolitotomy

Number of Metabolic Syndrome Components Is the Central Predictor of the Impact of Metabolic Syndrome on Outcome of Percutaneous Nephrolithotomy in Staghorn Nephrolithiasis

Introduction: How to quantify the impact of metabolic syndrome (MetS) on percutaneous nephrolithotomy (PCNL) is unclear. We aimed to evaluate the quantified effect of the number of MetS components on the outcome of PCNL. Materials and Methods: In this retrospective cohort study, consecutive 606 patients with idiopathic staghorn renal stones undergoing PCNL were included. The participants were divided into two groups: MetS(+) and MetS(-). The number of MetS components were calculated as 0 to 5. Primary outcomes were stone-free rate (SFR) and overall complication rate. Results: MetS, obesity, hypertension, increased triglycerides (TG), decreased high-density lipoprotein cholesterol (HDL), and diabetes mellitus were found in 24.1%, 38.1%, 70.0%, 29.9%, 34.5%, and 26.4% of the patients, respectively. SFR values were comparable between groups. MetS resulted in a higher rate of overall complication (p < 0.001, odds ratio [OR] = 2.4, 95% confidence interval [CI] 1.67-3.69), blood transfusion, urosepsis, larger hemoglobin deficiency, and length of hospital stay. Multivariable analysis confirmed that fasting plasma glucose (FPG) (p = 0.033, OR = 1.164, 95% CI 10.22-1.348) and number of MetS components (p = 0.001, OR = 1.496, 95% CI 1.184-1.890) were independent risk factors, whereas HDL (p = 0.014, OR = 0.428, 95% CI 0.217-0.837) played an independent protective role. Compared with 0, having 3, 4, and 5 MetS components was associated with stepwise increase in complication rate (19.5% vs 34.2%, 41.5%, 62.5%, p = 0.027, 0.006, <0.001; OR = 2.1, 2.9, 6.9). Subgroup analysis showed that MetS(+) patients without complications were associated with lower systolic blood pressure, TG, and FPG (p = 0.010, 0.031, 0.002, respectively). Conclusions: The number of MetS components is the central predictor in assessing both inner severity of MetS and outer risk for PCNL. The number of MetS components is recommended to be calculated on a scale of 0 to 5. Three, four, and five MetS components increase risk for PCNL in a stepwise manner regardless of the presence or absence of obesity. MetS components should be controlled preoperatively.

Metabolic Syndrome Increases Risk of Postoperative Myocardial Infarction Following Percutaneous Nephrolithotomy

INTRODUCTION

Percutaneous nephrolithotomy (PCNL) is the gold standard treatment for upper tract stone burdens greater than 2 cm. Metabolic syndrome (MetS) is a constellation of conditions (diabetes mellitus, hypertension, dyslipidemia, and obesity) and is a risk factor for nephrolithiasis. Our objective was to investigate adverse cardiovascular outcomes of PCNL in patients with comorbid MetS diagnoses.

MATERIALS AND METHODS

Data from the Healthcare Cost and Utilization Project State Inpatient Database for Florida and California were used to identify PCNL patients (ICD9: 55.03, 55.04) between 2007 and 2011. Patients were categorized having 0, 1-2, or 3-4 components of MetS. Postoperative myocardial infarction (MI) and inhospital mortality rate outcomes were identified. Multivariate logistic regression was used to control for patient characteristics (age, race, and primary insurance provider) and medical comorbidities.

RESULTS

PCNL was performed on 39,868 patients, of whom 17,932 (45.0%) had no MetS conditions, 19,268 (48.3%) had 1-2 MetS conditions, and 2668 (6.7%) had 3-4 MetS conditions. With increasing MetS conditions, patients had increased incidence of postoperative MI (0: 0.6%; 1-2: 1.0%; 3-4: 1.8%, p < 0.001). On multivariate analysis, the presence of 3-4 MetS comorbidities increased the odds of a postoperative MI (1-2: odds ratio [OR] 1.2, 95% confidence interval [CI] 0.94-1.53, p = 0.147; 3-4: OR 2.2, 95% CI 1.54-3.15, p < 0.001).

CONCLUSIONS

MetS patients have an increased risk of MI following PCNL given their pre-existing comorbidities. Routine preoperative cardiac testing may benefit this population before PCNL.