Defining radical cystectomy using the ICD-10 procedure coding system

Introduction: The International Classification of Diseases-10-Procedure Coding System (ICD-10-PCS) is markedly more complex than the preceding ICD-9 system, which has increased the difficulty of identifying radical cystectomy (RC) in administrative datasets. Given the absence of a consensus code definition for RC, we sought to develop and internally validate a list of ICD-10-PCS codes for RC.

Materials and methods: All RCs performed from January 2019 to December 2020 were identified from our prospectively maintained registries and split into training (2019) and validation (2020) cohorts. A list of candidate ICD-10-PCS codes to identify RC were compiled using an online ICD-9 to ICD-10 converter. Codes were used to identify RCs from hospital billing data and referenced against registry cases in the training cohort; when discrepancies were found, the working ICD-10 code definition was iteratively revised. Accuracy of the consensus code list was verified in the validation cohort.

Results: We identified 459 RCs over the study period, including 225 in 2019 and 234 in 2020. In the training cohort, our codes identified 241 procedures, including 222 of 225 (99%) RCs performed for bladder cancer. Misidentified cases included 15 (6.2%) RCs for benign disease or nonurologic cancers and 4 (1.7%) non-RC cases. In the validation cohort we identified 239 cases, including 227 of 234 (97%) RCs for bladder cancer and 12 (5%) RCs for benign disease or nonurologic cancers.

Conclusion: Given high fidelity to actual procedures performed, this list of ICD-10-PCS codes may be useful for researchers seeking to identify RC within administrative datasets.