Combined use of DECAF score with bun and troponin to predict mortality in COPD attack patients

Objective: Chronic obstructive pulmonary disease (COPD) is the third leading cause of death worldwide. This study aims to investigate the effectiveness of combining the DECAF score with blood urea nitrogen (BUN) and troponin levels in predicting in-hospital mortality among COPD patients.Materials and Methods: Between June 1, 2024, and May 1, 2025, a total of 117 patients admitted to the Department of Pulmonology and the tertiary intensive care unit of Dicle University Faculty of Medicine due to COPD exacerbation were included in the study. Patients were evaluated according to the GOLD guidelines, and the mMRC dyspnea scale was applied. Data collected included age, sex, smoking history, radiological findings, ECG, arterial blood gas analysis, complete blood count, renal function tests, troponin levels, and in-hospital mortality.Inclusion criteria were: age ≥35 years, hospitalization due to COPD exacerbation, a smoking history of ≥10 pack-years, and confirmed airway obstruction (FEV1/FVC < 0.7 after bronchodilator use). The exclusion criterion was the presence of a comorbidity limiting survival (e.g., metastatic malignancy). Data were analyzed using SPSS version 26.0. Numerical variables were expressed as mean ± standard deviation or median (minimum–maximum), and categorical variables as numbers and percentages. The chi-square test was used for categorical variables. Logistic regression was performed to identify factors associated with mortality, and odds ratios (OR), 95% confidence intervals (CI), and p-values were reported. The diagnostic performance of the DECAF score and biochemical markers (troponin, urea) was evaluated using ROC analysis, and AUC, sensitivity, specificity, and cut-off values were calculated. A p-value of <0.05 was considered statistically significant. Results:Of the 117 patients included in the study, 95% were male. The mortality rate was 27%. The most common comorbidities were hypertension (34%), coronary artery disease (19%), and diabetes mellitus (17%). The mean age was 72.07 ± 9.29 years (range: 50–96), and the average smoking history was 47.17 ± 18.25 pack-years.According to the ROC analysis, troponin (AUC=0.785, p<0.001), DECAF score (AUC=0.732, p<0.001), and urea (AUC=0.620, p=0.046) were statistically significant predictors of mortality. The calculated cut-off values were DECAF ≥2.5, troponin ≥21.45, and urea ≥52.8. Logistic regression analysis showed that each one-point increase in DECAF score increased the mortality risk by 1.735 times (p=0.004), and higher troponin levels increased mortality risk by 1.105 times (p=0.014). Urea levels were not significantly associated with mortality (p=0.273). The model's accuracy was 77.8%, with a Cox & Snell R² of 0.182 and Nagelkerke R² of 0.264. According to DECAF risk classification, 41% of the patients were in the high-risk group. With the addition of troponin, this rate decreased to 30%; with the addition of urea, it was 32%; and when all three parameters were combined (DECAF+Troponin+Urea), the high-risk group rate dropped to 23%. All classifications (DECAF, DECAF+Troponin, DECAF+Urea, DECAF+Troponin+Urea) showed a statistically significant relationship with in-hospital mortality (p=0.003, p<0.001, p=0.010, and p=0.001, respectively). In all models, mortality rates increased significantly with higher risk levels. Particularly, the DECAF+Troponin and DECAF+Troponin+Urea combinations provided better discrimination in predicting mortality.According to ROC analysis, the DECAF+Troponin combination had the highest diagnostic accuracy (AUC=0.780, p<0.001) and a sensitivity of 0.844. The DECAF+Urea (AUC=0.735) and DECAF+Troponin+Urea (AUC=0.772) combinations were also significant (p<0.001), with cut-off values of 2.5 and 3.5, respectively. In logistic regression models including these combinations, only the DECAF+Urea model was statistically significant (p=0.048), indicating that increasing urea levels were associated with decreased mortality risk (OR: 0.374). Although not statistically significant, the DECAF+Troponin (p=0.355) and DECAF+Troponin+Urea (p=0.118) models showed trends toward increased mortality risk (1.7-fold and 2.9-fold, respectively). The model's accuracy was calculated as 72.6%. Conclusion: In this study, both the DECAF score and troponin level were found to be independent and significant predictors of in-hospital mortality in COPD patients. While urea alone had limited prognostic value, it contributed to improved mortality prediction when used in combination with other parameters. The addition of troponin to the DECAF score may aid in the early identification of high-risk patients. However, further validation through larger and multi-center studies is necessary. Keywords: COPD, DECAF Score, Mortality