Monocyte distribution width (MDW) has been associated with inflammation and poor prognosis in various acute diseases. Chronic obstructive pulmonary disease (COPD) exacerbations (ECOPD) are associated with mortality. The objective of this study was to evaluate the utility of the MDW as a predictor of ECOPD prognosis. This retrospective study included patient admissions for ECOPD. Demographic, clinical and biochemical information; intensive care unit (ICU) admissions; and mortality during admission were recorded. A total of 474 admissions were included. MDW was positively correlated with the DECAF score (r = 0.184, p < 0.001) and C-reactive protein (mg/dL) (r = 0.571, p < 0.001), and positively associated with C-RP (OR 1.115 95% CI 1.076–1.155, p < 0.001), death (OR 9.831 95% CI 2.981– 32.417, p < 0.001) and ICU admission (OR 11.204 95% CI 3.173–39.562, p < 0.001). High MDW values were independent risk factors for mortality (HR 3.647, CI 95% 1.313–10.136, p = 0.013), ICU admission (HR 2.550, CI 95% 1.131–5.753, p = 0.024), or either mortality or ICU admission (HR 3.084, CI 95% 1.624–5.858, p = 0.001). In ROC analysis, a combined MDW–DECAF score had better diagnostic power (AUC 0.777 95% IC 0.708–0.845, p < 0.001) than DECAF (p = 0.023), MDW (p = 0.026) or C-RP (p = 0.002) alone. MDW is associated with ECOPD severity and predicts mortality and ICU admission with a diagnostic accuracy similar to that of DECAF and C-RP. The MDW– DECAF score has better diagnostic accuracy than MDW or DECAF alone in identifying mortality or ICU admission.
