Accuracy of identifying diagnosis of moderate to severe chronic kidney disease in administrative claims data

Background: Prior validation studies of claims-based definitions of chronic kidney disease (CKD) using ICD-9 codes reported overall low sensitivity, high specificity, and variable but reasonable PPV. No studies to date have evaluated the accuracy of ICD-10 codes to identify a US patient population with CKD. Methods: We assessed the accuracy of claims-based algorithms to identify adults with CKD Stages 3-5 compared with laboratory values in a subset (similar to 40%) of a US commercial insurance claims database (Optum's de-identified Clinformatics (R) Data Mart Database). We calculated the positive predictive value (PPV) of one or two ICD-9 (2012-2014) or ICD-10 (2016-2018) codes for CKD compared with a lab-based estimated glomerular filtration rate (eGFR) occurring within prespecified windows (+/- 90 days, +/- 180 days, +/- 365 days) of the ICD-based CKD code(s). Results: The study population ranged between 104 774 and 161 305 patients (ICD-9 cohorts) and between 285 520 and 373 220 patients (ICD-10 cohorts). The mean age was 74.4 years (ICD-9) and 75.6 years (ICD-10) and the median eGFR was 48 ml/min/1.73 m(2). The algorithm of two CKD codes compared with a lab value +/- 90 days of the first code achieved the highest PPV (PPV 86.36% [ICD-9] and 86.07% [ICD-10]). Overall, ICD-10 based codes had comparable PPVs to ICD-9 based codes and all ICD-10 based algorithms had PPVs >80%. The algorithm of one CKD code compared with laboratory value +/- 180 days maintained the PPV above 80% but still retained a large number of patients (PPV 80.32% [ICD-9] and 81.56% [ICD-10]). Conclusion: An ICD-10-based definition of CKD identified with sufficient accuracy a patient population with CKD Stages 3-5. Our findings suggest that claims databases could be used for future real-world research studies in patients with CKD Stages 3-5.

Automated summary

Validation studies compared ICD-9 and ICD-10 codes with laboratory values to identify CKD Stages 3-5 patients, finding that a two-code algorithm combined with lab results within +/- 90 days achieved the highest PPV. ICD-10 codes showed comparable accuracy to ICD-9 codes, with all ICD-10 algorithms having PPVs >80%.