Background/Purpose: Antineutrophil cytoplasmic antibody (ANCA) vasculitis (AV) is a complex group of autoimmune disorders affecting blood vessels in multiple organ systems. Delays in diagnosis are common because AV symptoms can be non-specific and present heterogeneously. This may result in increased healthcare utilization in the months preceding diagnosis. We examined whether Medicare beneficiaries with AV experience increased healthcare utilization and costs in the year before the first diagnosis was recorded in claims, relative to Medicare beneficiaries without AV.

Methods: This retrospective cohort study used 2015-16 Medicare Part A/B medical claims and Part D prescription drug data. Beneficiaries with newly diagnosed AV were identified by having ≥1 inpatient claim or ≥2 non-inpatient claims at least 7 days apart in 2016 with an ICD-10 code for granulomatosis with polyangiitis, microscopic polyangiitis, or eosinophilic granulomatosis with polyangiitis, with no AV claims in the year prior. Beneficiaries with AV were matched 1:1 on age and sex to beneficiaries without any diagnosis codes for any type of systemic vasculitis in 2016. The study index date for AV beneficiaries was the first AV claim in 2016, which also served as the index date for the matched control. Beneficiaries were required to have continuous enrollment in Parts A, B, and D in the year prior to index. Outcomes included annual Medicare and beneficiary expenditures for Part A/B medical services, Part B and D medications, and annual counts of events in 12 categories of medical services (e.g., inpatient stays, outpatient visits, tests), for the year prior to the index date. Linear regression was used to test for differences, controlling for race/ethnicity, dual Medicaid enrollment or the Part D low-income subsidy, entitlement due to disability, and US region. Bias-corrected bootstrapped standard errors were used to calculate 95% confidence intervals (CI), accounting for non-normal distributions of dependent variables.

Results: A total of 1,626 AV beneficiaries and 1,626 matched controls met study criteria (mean age = 70.4 years, 62% female). The mean (SD) unadjusted Medicare and beneficiary Part A/B payments in the year prior to diagnosis were $23,445.23 (33,646.70) and $4,380.64 (5,064.45) for AV beneficiaries, respectively, and $10,136.05 (19,944.70) and $1,907.44 (3,292.49) for matched controls (Table 1). Adjusted regression analyses revealed that AV beneficiaries had significantly higher Medicare and beneficiary payments for all cost categories, and higher number of all types of utilization events, compared to matched controls (p< 0.001).  Of note, AV beneficiaries on average incurred an additional $13,726 (95% CI: $11,946-$15,845) in Medicare Part A/B expenditures and had 21.2 (95% CI: 18.3-24.5) more hospital outpatient visits vs. matched controls.

Conclusion: In the year prior to AV diagnosis, Medicare beneficiaries have significantly higher healthcare utilization and costs when compared to age- and sex-matched beneficiaries without AV. This study highlights that pre-diagnosis manifestations in AV can be costly and further improvement may be needed to allow for timely diagnosis.

Table 1. Total one-year utilization and costs prior to diagnosis for AV beneficiaries and matched controls

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ACR Meeting Abstracts - https://acrabstracts.org/abstract/healthcare-utilization-and-costs-prior-to-diagnosis-of-anca-vasculitis-in-medicare-beneficiaries/