Prognostic Value of RDW and Its Contribution to Scoring Systems in Patients with Chronic Obstructive Pulmonary Disease

Background In recent years, the systemic effects observed in COPD have led to significant changes in various commonly used hematological and biochemical parameters. It has been demonstrated that these parameters can serve as prognostic markers; however, the impact of these biomarkers on prognostic models has not been sufficiently explored. This study aims to develop a prognostic model incorporating easily accessible biomarkers to predict mortality in COPD patients and to evaluate the effect of integrating prominent biomarkers into existing scoring systems. Methods This retrospective study analyzed 355 COPD patients in two cohorts: derivation (n = 136) and validation (n = 219). Variables associated with 10-year mortality were identified via univariate analyses. A prognostic model was developed using multivariate Cox regression, LASSO, and bootstrap resampling. Its performance was compared to established scoring systems (ADO, DOSE, and BODEX), and the independent prognostic value of a key biomarker was assessed. Results Age, FEV1%, mMRC dyspnea scale, and RDW emerged as robust predictors of 10-year mortality. The four-variable model demonstrated high predictive accuracy (c-index: 0.823), outperforming ADO (0.797), DOSE (0.690), and BODEX (0.707). Incorporating RDW into existing systems significantly enhanced their accuracy (c-index with RDW added: 0.823, 0.741, and 0.750). RDW’s effect on mortality was independent of hemoglobin levels and remained significant within normal ranges. Conclusion The model constructed with age, FEV1%, mMRC dyspnea score, and RDW demonstrates strong performance in predicting mortality among COPD patients. Importantly, the influence of biomarkers like RDW on established scoring systems has not been extensively studied, highlighting the originality and significance of this research. RDW stands out as an independent and effective predictor, improving the accuracy and calibration of prognostic models. Elevated RDW levels—even within normal reference ranges—are associated with increased mortality risk, suggesting that current laboratory reference intervals should be reconsidered in clinical practice. With its low cost and wide availability, RDW offers a practical solution to enhance clinical prognostic models and improve their utility.