Admission Albumin-Corrected Anion Gap and Subsequent Tricuspid Regurgitation Velocity Elevation After COPD Exacerbation

Admission albumin-corrected anion gap (ACAG) may reflect metabolic stress during an acute exacerbation of chronic obstructive pulmonary disease (AECOPD), but its relationship with subsequent pulmonary vascular abnormalities is unclear. This study included 294 adults hospitalized with AECOPD between January 2022 and November 2024 in a single-center retrospective cohort. Participants had baseline tricuspid regurgitation velocity (TRV) <3.4 m/s and at least one follow-up echocardiogram. The primary endpoint was first detected TRV ≥3.4 m/s within 12 calendar months after discharge. During available follow-up, 105 participants (35.7%) reached the endpoint and 12 died before detection. Each 5 mmol/L higher ACAG was associated with an adjusted odds ratio of 2.17 (95% CI, 1.51-3.11) and a cause-specific hazard ratio of 1.66 (95% CI, 1.34-2.05). A sensitivity analysis using TRV >3.4 m/s identified 99 events and gave an adjusted odds ratio of 1.90 (95% CI, 1.32-2.75). Adding ACAG to the clinical reference model increased the cross-validated area under the curve from 0.803 to 0.829; the extended-model calibration slope was 0.823. Among participants without a detected event, the last readable echocardiogram occurred a median of 323 days after discharge. Admission ACAG was associated with subsequent TRV elevation and provided modest additional discrimination in this cohort. Its availability in routine admission testing makes it a candidate for further evaluation in post-exacerbation risk assessment, with prospective external validation needed before clinical application.