Objective This study aimed to evaluate and compare the predictive accuracy of five established clinical scoring systems - CURB65, BAP65, qSOFA, DECAF, and NEWS - in forecasting in-hospital mortality and the need for mechanical ventilation among patients presenting with acute exacerbation of chronic obstructive pulmonary disease (AECOPD) in the emergency department. Methods An observational, cross-sectional study was conducted over a 12-month period (January to December 2023) in the emergency department of Indira Gandhi Institute of Medical Sciences, Patna. A total of 200 patients aged 18 years and older with AECOPD were enrolled. Clinical, laboratory, radiographic, and electrocardiographic data were collected to calculate the prognostic scores. The primary outcome was in-hospital mortality
the secondary outcome was the requirement for mechanical ventilation. Statistical analyses were performed using IBM SPSS Statistics for Windows, Version 26.0 (Released 2019
IBM Corp., Armonk, NY, USA) and included logistic regression, receiver operating characteristic curve analysis, calibration assessment, and evaluation of seasonal variations in score performance. Results Among the five scoring systems, the DECAF score showed the highest predictive accuracy with an area under the curve (AUC) of 0.80, followed by BAP65 (0.75), NEWS (0.72), CURB65 (0.70), and qSOFA (0.65). DECAF had the strongest association with hospital mortality (OR: 2.8, 95% CI: 1.7-4.5) and need for mechanical ventilation (OR: 2.3, 95% CI: 1.5-3.6). It also achieved the highest sensitivity (0.85) and specificity (0.75). ANOVA revealed significant differences in AUC values across scores (F = 4.76, p = 0.002). Calibration curves indicated accurate prediction for DECAF and BAP65. Seasonal analysis demonstrated consistent performance for both DECAF and BAP65 throughout the year. Conclusions The DECAF score was the most reliable predictor of hospital mortality and mechanical ventilation needs in AECOPD patients presenting to the emergency department. BAP65 also performed consistently well and may serve as a practical alternative, particularly in resource-limited settings. Condition-specific scores like DECAF should be favored over general severity indices for effective risk stratification in COPD.