# Comparing Claims Data to Stroke and Bleeding in the NCDR Left Atrial Appendage Occlusion Registry

## TL;DR

This study compares Medicare claims data with registry-reported stroke and bleeding events after a heart procedure, finding that claims data often overestimate event rates.

## Contribution

The study evaluates the accuracy of claims data for postmarketing surveillance of left atrial appendage occlusion outcomes.

## Key findings

- Claims data had moderate agreement with registry-reported events for stroke and bleeding.
- Claims overestimated event rates for most outcomes compared to registry data.
- Nonclaims-based methods are recommended for accurate postmarketing surveillance.

## Abstract

Claims data are increasingly used for postmarketing surveillance of therapies such as transcatheter left atrial appendage occlusion (LAAO), but their accuracy remains uncertain.

This study aimed to compare stroke and bleeding events in the National Cardiovascular Data Registry LAAO Registry with claims data.

LAAO Registry data for patients aged ≥65 years were linked to 2016 to 2021 Medicare claims. Primary diagnosis International Classification of Diseases-Tenth Revision codes from inpatient hospitalizations were compared to adjudicated registry-reported stroke and major bleeding events after discharge, including estimation of sensitivity and positive predictive value of claims for identifying registry-reported events. Kappa statistics and incidence rates were also assessed.

Among 71,043 LAAO Registry patients, sensitivity and positive predictive value of claims were 60.8% and 50.5% for ischemic stroke (kappa 0.55), 42.7% and 50.5% for hemorrhagic stroke (kappa 0.46), 55.9% and 40.3% for gastrointestinal bleeding (GIB) (kappa 0.43), 62.2% and 38.0% for intracranial hemorrhage (kappa 0.47), and 20.4% and 10.0% for other major bleeding (kappa 0.12). Sensitivity and negative predictive values were >92% for all events. Two-year incidence rates were higher in claims vs registry data for ischemic stroke (2.5% vs 2.2%), GIB (6.8% vs 5.2%), intracranial hemorrhage (1.6% vs 1.1%), and other bleeding (3.1% vs 1.5%; P < 0.01 for all events), and lower for hemorrhagic stroke (0.4% vs 0.5%; P = 0.03).

In the LAAO Registry, International Classification of Diseases-Tenth Revision codes have moderate agreement with stroke, GIB, and intracranial hemorrhage, and overestimate most event rates compared to adjudicated registry-reported events. Nonclaims-based methods are needed to ensure accurate assessment of clinical events in postmarketing surveillance.