Impact of race-based calculations of eGFR on the management of muscle invasive bladder cancer.

Purpose: The estimated glomerular filtration rate (eGFR) has historically been calculated with a race-coefficient multiplier (RCM); however, the RCM has been broadly criticized as inaccurate and a potential contributor to exacerbating disparities. We evaluated the impact of the RCM on eGFR and examined the 30-day post-cystectomy complications in a muscle-invasive bladder cancer cohort.

Materials and methods: We retrospectively analyzed patients diagnosed with MIBC who underwent cystectomy in the ACS NSQIP database from 2006 to 2020 using CPT and ICD codes. The eGFR was computed using the Modification of Diet in Renal Diseases equation which has RCM = 1.212 for black patients. Using the race data field, patients were categorized into Black and non-Black. The eGFR cut-off of 60 mL/min/1.73 m² was chosen for patient stratification because it represents a key clinical threshold in the classification of chronic kidney disease and influences various care decisions such as chemotherapy choice. Subsequently, we examined the 30-day post-cystectomy cardiovascular and pulmonary (CV&P) complications in these patients stratified by their eGFR using descriptive statistics and a multivariable logistic regression model.

Results: The application of the RCM to estimate eGFR in the Black cohort increased the mean eGFR from 57.8 to 70.0 ml/min/1.73 m² (P = 0.001) which led to a 17.3% (45.6% vs 62.9%, P = 0.001) increase in the proportion of Black patients with eGFR≥60 ml/min/1.73 m². The rate of CV&P complications post-cystectomy among this group of 17.3% of patients in the Black cohort was 7.6% compared to a 4.3% complication rate among a non-Black cohort matched for similar eGFR for whom RCM was not applied (P = 0.06). Black patients in this RCM-dependent category of eGFR≥60 mL/min/1.73 m² had higher adjusted odds of developing 30-day post cystectomy CV&P complications compared to eGFR-matched non-Black patients (OR = 2.2, 95% CI = 1.13-4.31, P = 0.02).

Conclusion: In this study, we found that inclusion of RCM in the eGFR significantly increases the proportion of Black patients with eGFR≥60. This RCM might also be associated with higher post-cystectomy CV&P complications; therefore, future studies are needed to evaluate the implications of race-based algorithms on outcomes.