Introduction: The modified 5-item frailty index (mFI-5) is a validated and concise comorbidity-based risk stratification tool that predicts adverse outcomes following surgery. In urology, there is limited literature on the impact of frailty on percutaneous nephrolithotomy (PCNL) outcomes. We sought to evaluate the mFI-5 for identifying high risk patients prior to PCNL. Methods: Adult patients who underwent PCNL between 2015 to 2019 were identified from the National Surgical Quality Improvement Program database using Current Procedural Terminology codes. Patient frailty was assessed using the mFI-5 index, which is assessed between 0 to 5 for the cumulative presence of the five components (not frail [NF] 0, slightly frail [SF] 1, and frail [F]>2). Primary outcomes were 30-day postoperative complications. Secondary outcomes were hospital utilization: total hospital length of stay, reoperation, and unplanned readmission. Odds ratios with 95% confidence intervals (CI) and P values (a=0.05) were estimated using multivariate regression controlling for baseline variables that were significantly different between groups. Results: From a total of 265 PCNL patients included for analysis, 58.7% (n=123) were not frail, 31.3% (n=83) were slightly frail, and 22.2% (n=59) were frail. After controlling for covariates, among all PCNL patients, frailty was not associated with 30-day postoperative complications (F= OR: 0.98, 95% CI[0.13-7.24], p=0.980; SF= OR: 2.02, 95% CI[0.64-6.45], p=0.227). Compared to non-frail patients, increased frailty was not associated with increased healthcare utilization in terms reoperation (F= OR: 0.49, 95% CI[0.04-5.69], p<0.575; SF= OR: 0.99, 95% CI[0.27-3.92], p=0.904) or unplanned readmission (F= OR: 1.40, 95% CI[0.05-33.2], p<0.840; SF= OR: 0.61, 95% CI[0.10-2.81], p=0.543). Compared to non-frail patients, patients that were slightly frail were more likely stay longer in hospital (F: 4.0±3.7 v. SF: 4.3±5.7 v. NF: 2.4±2.3; p=0.001). Conclusions: Frailty is associated with longer hospital stay but not 30-day postoperative complications, readmission, or reoperation after PCNL. These results assist surgeons in counselling patients on expected course and hospital stay following PCNL. More data is required to identify whether technical rather than patient factors may explain outcomes following PCNL. SOURCE OF Funding: None.
