Purpose: To describe the clinical characteristics of struvite stones and determine the preoperative predictors of sepsis in struvite patients undergoing percutaneous nephrolithotomy (PCNL).
Methods: A retrospective study of patients who underwent PCNL between April 2011 and March 2018 was performed. The data of the struvite stones and non-struvite stones groups were compared following propensity score matching. Subsequently, the struvite stones group was sub-divided for further analysis according to the Sepsis-3 definition: non-sepsis and sepsis groups.
Results: After matching based on age, gender, BMI, and number of access tracts, the comparative analysis showed that staghorn calculi and higher Guy's stone score were more frequently observed in non-struvite stone patients (n = 97), while a history of urolithiasis surgery (56.70%), preoperative broad-spectrum antibiotic therapy (53.61%), positive preoperative urine culture (55.67%), and sepsis (35.05%) after surgery were more common in patients (n = 97) with struvite stones (all P values < 0.05). Eighteen (18.56%) patients presented with multidrug-resistant (MDR) bacteriuria. Multivariate analysis demonstrated that the preoperative presence of MDR bacteriuria (OR = 3.203; P = 0.043) and increased serum creatinine (OR = 3.963; P = 0.010) were independent risk predictors of sepsis. The two factors were used to construct a nomogram to predict the probability of sepsis. The nomogram was well calibrated and had moderate discriminative ability (concordance index: 0.711).
Conclusion: Our study revealed that patients with struvite stones were associated with a significantly high risk of calculi recurrence and sepsis after surgery. The presence of MDR bacteriuria preoperatively was a reliable factor to predict sepsis.
Keywords: Multidrug resistant; Percutaneous nephrolithotomy; Renal calculi; Struvite.