Introduction: Bladder outlet obstruction (BOO) is common in older adults. As such, many who pursue surgery have additional vulnerabilities affecting surgical risk, including frailty and other comorbidities. No risk calculator for BOO surgery that factors in frailty exists. We developed the first risk calculator for BOO surgeries that includes components of frailty and comorbidity to predict the risk of common complications. Methods: Medicare beneficiaries undergoing BOO surgery from 2014-2016 were examined using Medicare MedPAR, Outpatient, and Carrier files. Pre-procedure frailty was quantified for each subject using the 93-item Claims-Based Frailty Index (CFI). Each variable in the Charlson Comorbidity Index and CFI was extrapolated into stepwise logistic regression models to determine variables most predictive of surgical complications. The most prognostic variables were grouped into 13 categories. C-statistics, Brier scores, Spiegelhalter p values and model fit curves were calculated to assess model fit. Results: A total of 212,543 subjects were included. BOO surgeries included transurethral resection of the prostate, GreenLight Laser Therapy, transurethral incision of the bladder neck, holmium laser enucleation of the prostate, transurethral microwave thermotherapy, transurethral incision of the prostate, UroLift, and transurethral needle ablation. Most subjects were white (88%), with CFI scores that were not frail (CFI <0.15, N=101,282, 48%) or pre-frail (0.15=CFI <0.25, N=10,559, 39%). Variables most predictive of complications were congestive heart failure, primary malignancy, secondary or metastatic malignancy, pneumonia/influenza in the past year, neurodegenerative/neurologic diseases, dementia/psychiatric conditions and substance use, renal disease, chronic liver disease, anemias/platelets disorders, chronic lung disease, coronary artery disease, venous/lymphatic/thrombotic disorders, and stroke. Model fit for any complication within 30 days of surgery is shown (Figure). Conclusions: This is the first risk calculator for BOO surgery that includes predictors of frailty and comorbidity to individualize risk calculation among older adults. This serves as an effective and widely-applicable tool to help guide patient counseling and clinical decision-making. SOURCE OF Funding: NIH-NIA R01AG058616
