Admission ACAG was associated with subsequent TRV elevation and provided modest additional discrimination in this cohort, making it a candidate for further evaluation in post-exacerbation risk assessment, with prospective external validation needed before clinical application.
Key Findings
Results
About one third of patients hospitalized with AECOPD and a normal baseline TRV developed TRV ≥3.4 m/s within 12 months after discharge.
Single-center retrospective cohort of 294 adults hospitalized with AECOPD between January 2022 and November 2024.
All participants had baseline TRV <3.4 m/s and at least one follow-up echocardiogram.
105 participants (35.7%) reached the endpoint of first detected TRV ≥3.4 m/s within 12 calendar months after discharge.
12 participants died before detection.
Results
Higher admission ACAG was independently associated with greater odds of subsequent TRV elevation.
Each 5 mmol/L higher ACAG was associated with an adjusted odds ratio of 2.17 (95% CI, 1.51-3.11).
The estimate was from the primary endpoint of first detected TRV ≥3.4 m/s within 12 calendar months.
Results
Higher admission ACAG was associated with a higher cause-specific hazard of TRV elevation in time-to-event analysis.
Each 5 mmol/L higher ACAG corresponded to a cause-specific hazard ratio of 1.66 (95% CI, 1.34-2.05).
Cause-specific analysis accounted for the 12 deaths occurring before detection of the endpoint as a competing event.
Results
The association persisted in a sensitivity analysis using a stricter TRV threshold of >3.4 m/s.
The sensitivity analysis identified 99 events.
The adjusted odds ratio was 1.90 (95% CI, 1.32-2.75).
Results
Adding ACAG to a clinical reference model modestly improved discrimination.
Cross-validated area under the curve increased from 0.803 to 0.829.
The extended-model calibration slope was 0.823.
Results
Follow-up echocardiography among participants without a detected event was relatively extended but variable.
Among participants without a detected event, the last readable echocardiogram occurred a median of 323 days after discharge.
Follow-up was limited to available echocardiograms, so event detection depended on imaging timing.
Conclusions
The authors conclude ACAG is a candidate marker for further evaluation but requires prospective external validation before clinical use.
ACAG is available from routine admission testing.
The study was single-center and retrospective.
Discrimination gain was described as modest.
What This Means
This study looked at patients hospitalized for a flare-up of chronic obstructive pulmonary disease (COPD) to see whether a routine blood-test measure taken on admission, called the albumin-corrected anion gap (ACAG), could hint at later problems in the blood vessels of the lungs. The researchers reviewed records of 294 patients whose heart ultrasound initially showed normal tricuspid regurgitation velocity (TRV), a marker used to estimate pressure in the lung circulation. About 36% (105 patients) later showed an elevated TRV (3.4 m/s or higher) within a year of leaving the hospital.
Patients with higher ACAG on admission were more likely to develop this elevated TRV. For every 5 mmol/L higher ACAG, the odds of elevation were roughly doubled (adjusted odds ratio 2.17), and the rate of developing it over time was about 66% higher. The finding held up when a slightly stricter cutoff was used. Adding ACAG to a model with other clinical information improved its ability to tell who would and would not develop elevation only modestly (AUC from 0.803 to 0.829).
This research suggests ACAG, which is already available from routine tests, might eventually help identify COPD patients at higher risk of lung vascular changes after a flare-up. However, the study was done at a single hospital and looked back at existing records, and follow-up heart scans were not done on a fixed schedule. The authors state that prospective studies in other settings are needed before ACAG could be used in clinical practice.
Zhao Z, Zhou X, Lu X, Zou S. (2026). Admission Albumin-Corrected Anion Gap and Subsequent Tricuspid Regurgitation Velocity Elevation After COPD Exacerbation.. Journal of visualized experiments : JoVE. https://doi.org/10.3791/74129