Oral Anticoagulant Initiation in Patients With Kidney Failure on Hemodialysis Newly Diagnosed With Atrial Fibrillation (2007-2020): An Observational Study of Trends and Disparities

Abstract

Rationale & Objective

Atrial fibrillation (AF) is common in patients with kidney failure on hemodialysis (HD), but few patients receive oral anticoagulant (OAC) treatment. Availability of direct-target OACs starting in 2010 may have induced greater OAC initiation, but this has not been systematically studied.

Study Design

Retrospective cohort study.

Setting & Participants

Using Medicare fee-for-service billing claims (2006-2020), we identified previously OAC-naïve HD patients newly-diagnosed with AF between January 1, 2007, and October 1, 2020.

Exposures

Calendar year; race/ethnicity.

Outcomes

OAC initiation within 90 days from AF diagnosis (any; specific agent).

Analytical Approach

We estimated initiation risk ratios for each calendar year compared with the referent cohort, 2007, using unadjusted and multivariable-adjusted modified Poisson regression. We also determined differences by racial/ethnic group in OAC initiation, as well as any changes in these disparities over time.

Results

Among 82,389 HD patients newly-diagnosed with AF, 20,002 (24.3%) initiated new OAC treatment within 90 days: 20.5% in 2007 and 34.1% in 2020. Direct-target OACs accounted for 81.0% of OAC initiations in 2020. Adjusted regression models estimated that OAC initiation remained essentially unchanged between 2007 and 2013, but thereafter increased toward a demographics-adjusted risk ratio of 1.61 (95% CI: 1.50-1.73) in 2020. Compared with non-Hispanic Whites, the rates of OAC initiation were 15% (95% CI, 12%-17%) lower among Black patients, 29% (95% CI, 24%-34%) lower among Asian patients, and 22% (95% CI, 19%-25%) lower among Hispanic patients. These disparities were not found to have differed across time (P_interaction = 0.75).

Limitations

Lack of clinical detail to firmly establish contraindications to OAC initiation.

Conclusions

While rates of OAC initiation among patients on HD with newly-diagnosed AF increased in recent years, predominantly driven by increased use of apixaban, OAC initiation rates remained low, at 34% of patients in 2020. Compared with non-Hispanic White patients, OAC initiation remained consistently lower in patients of other race and ethnic groups.

Plain-Language Summary

Use of oral blood thinners (anticoagulants) in patients with kidney failure undergoing hemodialysis who have a common type of heart rhythm disorder (atrial fibrillation) used to be low. We studied whether the availability of a novel class of anticoagulants increased use of this treatment approach in recent years. We were also interested in identifying any differences in anticoagulant use between patients of different racial and ethnic backgrounds. We found that use of anticoagulants in patients newly diagnosed with the heart rhythm disorder almost doubled between 2007 and 2020. We also found that Asian, Black, and Hispanic patients were less likely than non-Hispanic Whites to receive anticoagulants. The reasons for these differences are unclear and require further study.