Albumin, pH, PaCO2 and Alveolar-Arterial Gradient Difference Can Predict 30-Day Mortality in COPD Exacerbation

Introduction: Early treatment, prognosis and short-term mortality prediction of COPD exacerbation are substantial for physicians in the ED. To compare the A-a O-2 gradient (together with expected A-a O-2 gradient, A-a O-2 gradient difference), inflammatory markers (CRP, CAR, procalcitonin, NLR, PLR), and arterial blood gas (pH, pCO(2), lactate clearance) in predicting COPD exacerbation patients' 30-day mortality. Methods: A questionnaire was designed for each patient, including detailed demographic profile, smoking status, comorbidities, vital signs, laboratory results and outcomes (discharge, hospitalization, ICU, 30-day mortality). Results: 135 (60.3%) of the cases were male and 89 (39.7%) were female. Their ages ranged from 48 to 95 years, with an average of 72.22 +/- 10.09. The LOS of cases varied between 1 and 28 days, with an average of 7.00 +/- 3.83, ICU admission rate was 8% and the overall mortality rate was 5.4%. Albumin (AUC 0.81) and pH (AUC 0.68) showed the highest 30-day mortality prediction. While A-a O-2 gradient difference (AUC 0.68) showed the highest 30-day mortality prediction, expected A-a O-2 gradient (AUC 0.53) indicated a statistically lower 30-day mortality prediction. While PaCO2 (AUC 0.71) showed the highest 30-day mortality prediction, lactate clearance (AUC 0.54) indicated a statistically lower mortality estimation. Conclusion: Albumin is a strong predictor of 30-day mortality in COPD exacerbation patients in the ED. In addition, an arterial blood gas sampling measurement including pH, PaCO2 and A-a O-2 gradient difference are simple, precise and practical measurements for estimating 30-day mortality in these patients.