Validation of Antineutrophil Cytoplasmic Antibody–Associated Vasculitis as the Cause of End‐Stage Renal Disease in the US Renal Data System

Abstract

Objective. The objective of this study was to validate the diagnosis of antineutrophil cytoplasmic antibody (ANCA)-associated vasculitis (AAV) as the primary cause of end-stage renal disease (ESRD) in the US Renal Data System (USRDS).Methods. We identified patients with ESRD in the Mass General Brigham (MGB) health care system who were enrolled in the USRDS. The health records of those with AAV listed as the primary cause of ESRD in the USRDS were reviewed to confirm the diagnosis and estimate positive predictive value (PPV). Sensitivity was estimated by evaluating the primary cause of ESRD listed in the USRDS for patients with ESRD due to AAV in the MGB AAV cohort.Results. We identified 89 MGB patients with ESRD due to AAV in the USRDS. Of these, 85 cases were confirmed to be true cases of AAV (PPV = 94%). Among the patients classified as having AAV, 84 (99%) had an ANCA test, which was predominantly myeloperoxidase/P-ANCA (47 [55%]); 36 (42%) had a renal biopsy, and all biopsies were supportive of the diagnosis. The majority (81 [90%]) was identified as AAV by International Classification of Diseases Ninth Revision or International Classification of Diseases 10th Revision codes for granulomatosis with polyangiitis (446.4 or M313.1). Of the 77 MGB AAV cohort patients with ESRD who were linked to the USRDS, 41 (53%) had AAV listed as the cause of ESRD; in the remainder, ESRD was attributed to nonspecific nephritis.Conclusion. The diagnosis of AAV as the cause of ESRD in the USRDS has a high PPV; sensitivity was moderate. These findings support the continued use of the USRDS to study ESRD due to AAV.

Development and Validation of a Simulation Model for Treatment to Maintain Remission in Antineutrophil Cytoplasmic Antibody–Associated Vasculitis

“…We used data from the MGB AAV cohort and National Vital Statistics report to determine age‐ and sex‐specific monthly probabilities of death (see Supplementary Appendix A). We derived distinct age‐ and sex‐specific mortality rates for patients with ESRD from the US Renal Data System (14–16) and for patients hospitalized with severe infection from the Nationwide Inpatient Sample (see Supplementary Appendix A) (18).…”

“…The AAV-Sim simulates individuals who have achieved remission and have an eGFR of ≥45 ml/minute for which data are limited regarding ESRD risk. Among individuals with and without a history of renal involvement, we assumed that the monthly probability of ESRD during remission and major relapse is age dependent, derived from the MGB AAV cohort and rates of ESRD due to non-glomerulonephritis causes observed in the general population, respectively (see Supplementary Appendix A, available at http://onlinelibrary.wiley.com/doi/10.1002/acr.25088) (14)(15)(16). ESRD risk during minor relapse is the same as during remission among those with and without renal involvement at model start.…”

Longitudinal Patterns of Renal Function in Antineutrophil Cytoplasmic Antibody–Associated Vasculitis

“…Third, renal biopsies were not obtained in all patients, limiting our ability to associate specific renal biopsy features with trajectory membership. However, biopsies are uncommonly obtained in the context of positive ANCA tests with a consistent clinical context, as previously observed in our health care system (12). Fourth, our definition of renal treatment resistance may be biased by persistent hematuria in patients with renal damage despite lack of ongoing active vasculitis; however, the definition of treatment resistance reflects a similar definition used in another study assessing progression to ESRD in AAV.…”

“…This definition is similar to the one previously described by Lionaki et al (3). ESRD was defined as 1) a need for dialysis for >60 days, 2) dialysis until death if the patient died between 14 and 60 days of follow-up, or 3) renal transplant, as identified by chart review and US Renal Data System records (12).…”