The modified 5-item frailty index as a predictor of perioperative risk in patients undergoing percutaneous nephrolithotomy

Abstract

INTRODUCTION: The modified 5-item frailty index is a relatively new tool to assess the post-operative complication risks. In urology, there is limited literature on the impact of frailty on percutaneous nephrolithotomy (PCNL) outcomes. We aimed to compare the predictive value of the modified 5-item frailty index (mFI-5) to identify high risk patients prior to PCNL. METHODS: A database of patients undergoing PCNL, between 2015 and 2022, was analyzed. Patient frailty was assessed using the mFI-5 index. The mFI-5 index was calculated based on the presence of the five co-morbidities: congestive heart failure within 30 days prior to surgery, diabetes mellitus, chronic obstructive pulmonary disease, partially dependent or totally dependent functional health status at time of surgery, and hypertension requiring medication. Patients were grouped as not frail (mFI-5 = 0), intermediate (mFI-5 = 1), and severely frail (mFI-5 ≥ 2). Primary outcomes were 30-day postoperative complications. Secondary outcomes were hospitalization: total hospital length of stay, reoperation, and unplanned readmission. RESULTS: From a total of 320 PCNL patients included for analysis, 54.06% (n = 173) were not frail, 17.81% (n = 57) were intermediate, and 28.12% (n = 90) were severely frail. Frail patients were likely to be older (p = 0.002) and have a higher American Society of Anesthesiologists score (p = 0.001), chronic kidney disease (p < 0.001). Patients of intermediate or severe frailty were more likely to exhibit postoperative sepsis (p = 0.042), significant blood loss (p = 0.036) and require intensive care units admissions (p = 0.0015). Frail patients had a longer hospital length of stay (p < 0.001) and tended to require reoperation (p = 0.001), and unplanned readmission (p = 0.02). CONCLUSION: Frailty assessment appears useful in stratifying those at risk of extended hospitalization, septic and hemorrhagic complications, readmission, or reoperation after PCNL. Preoperative assessment of frailty phenotype may give insight into treatment decisions and assist surgeons in counselling patients on expected course and hospital stay following PCNL.