Predictive Accuracy of the 1‐h HACOR Score for Identifying Non‐Invasive Ventilation Failure in COPD Patients With Acute Hypercapnic Respiratory Failure: A Prospective Observational Study

ABSTRACT Background and Aims Chronic obstructive pulmonary disease (COPD) is frequently complicated by acute hypercapnic respiratory failure (AHRF) requiring non‐invasive ventilation (NIV). Early identification of NIV failure is important, as delayed recognition may worsen outcomes. This study evaluated the predictive utility of the 1‐h HACOR score for early identification of NIV failure in COPD patients. Methods A prospective observational study was conducted at the National Institute of Diseases of the Chest and Hospital, Dhaka, from May 2022 to September 2023. Ninety‐two patients of acute exacerbations of COPD with AHRF were purposively enrolled. Clinical parameters and HACOR scores were recorded at baseline and 1 h after NIV initiation. NIV failure was defined as death or need for intubation, classified as early (< 48 h) or late (≥ 48 h). Results About 13.1% patients experienced NIV failure. The HACOR score decreased significantly at 1 h of NIV initiation in the success group (8.16 ± 4.52 to 3.38 ± 2.93; p < 0.001) but remained persistently high in the failure group. A HACOR cut‐off value of ≥ 6 at 1 h predicted NIV failure with 91.67% sensitivity, 83.75% specificity, while ≥ 8 reliably identifies patients at high risk of early NIV failure with 100% sensitivity and 89.29% specificity. Conclusions The HACOR score was a simple and reliable bedside tool for early prediction of NIV failure in patients with acute exacerbation of COPD complicated by AHRF. Its routine use may facilitate timely reassessment and escalation of respiratory support, although larger multicenter studies are needed for further validation.