A75-11 Association Between Hospital Utilization and 6mw Heart Rate Metrics From the Hiflo Study

Introduction

High Flow Nasal Therapy (HFNT) is under investigation in patients with COPD to assess if therapy reduces exacerbations. HFNT may reduce gas trapping, improve mechanical efficiency, and decrease dynamic hyperinflation, providing a mechanistic rationale for exacerbation reductions. 6-minute walk testing (6MW) provides a physiologic assessment of cardiopulmonary reserve at rest and with stress, and may predict exacerbations, and responders to therapy. This study aims to evaluate associations between baseline 6MW HR parameters and hospital utilization in patients enrolled in the HiFlo trial.

Methods

HiFlo (NCT05204888), a phase 3 randomized control trial comparing HFNT plus usual care to usual care alone, in COPD patients, for at least 1 year. Baseline demographics, comorbidities, pulmonary function testing and exacerbations were collected. 6MW data including resting HR, Δ HR with exertion, and peak HR were obtained. Associations between 6MW HR parameters and hospital utilization were examined using Spearman correlation coefficients and Wilcoxon rank sum-tests.

Results

267 COPD patients (mean age 67.9±8.0, 50.6% female, 44.6 ± 38.7 pack years, BMI 27.0±7.1, mean FEV1% predicted was 41.0±16.1 (Table 1). Baseline hospitalizations were 2.2 ± 2.2, and 4.9% were intubated in the prior year. On 6MW, HR metrics had small positive association with moderate exacerbations (ΔHR r = 0.1562, p = 0.0134; peak HR r = 0.12623, p = 0.0462) and hospitalizations in the prior year (pre-walk HR r = 0.1291, p = 0.0414; peak HR r = 0.13567, p = 0.0320). Participants with ED visits in the past year tended to have higher pre-walk HR (0 ED visit median, quartiles: HR 80, 72 to 84; >0 ED visit HR: 84, 74.5 to 94; p = 0.0472. Participants with >1 hospitalization did not have significantly higher pre-walk HR but had higher ΔHR (1 hospitalization: median, quartiles: 8, 2-17; >1 hospitalization: 11, 4-23; p = 0.0416) and peak HR (1 hospitalization: 94, 83-103; >1 hospitalization: 99, 87-112; p = 0.0416,).

Conclusions

Baseline 6MW heart rate metrics (baseline, peak, and Δ) were associated with greater hospital utilization in patients with moderate-severe COPD enrolled in the HiFLo trial. These findings suggest baseline HR metrics from routine tests may help identify patients at higher risk of exacerbation and could inform patient selection in future studies.

This abstract is funded by: Fisher & Paykel Healthcare