Changes in Red Cell Distribution Width During Hospitalization for Community-Acquired Pneumonia: Clinical Characteristics and Prognostic Significance.

Purpose: We investigated outcomes of patients hospitalized with community-acquired pneumonia (CAP) according to the changes in red cell distribution width (RDW).

Methods: For 980 adults, clinical characteristics, outcomes during hospitalization for CAP (transfer to the intensive care unit, treatment with mechanical ventilation, prolonged hospital stay, and death), and all-cause mortality following discharge were compared: according to RDW changes versus stable RDW during hospitalization, and according to normal (≤14.7 %) versus high (>14.7 %) RDW values on admission/discharge.

Results: RDW changes (n = 386) during hospitalization were associated with more severe clinical and laboratory characteristics than stable RDW (n = 594). Changes in RDW strongly predicted poor in-hospital outcomes (p < 0.001). The respective 30, 90-day, and total (median follow-up 54 months) mortality rates were significantly higher (9.8, 16.0 and 43.5 %) among patients with RDW changes, compared to 4.0, 7.6 and 30.5 % among those with stable RDW (p < 0.001 for all comparisons). RDW changes, as well as high RDW (each 1 % increment) on admission and discharge, were powerful predictors of mortality (the respective relative risks 1.41, 1.13, and 1.15, and 95 % confidence intervals 1.13-1.74, 1.08-1.19, and 1.10-1.21).

Conclusions: RDW changes during hospitalization for CAP are common and associated with a severe clinical profile. Time-dependent RDW changes strongly predict poor in-hospital outcomes and increased short- and long-term mortality. Repeated RDW determinations during hospitalization for CAP may provide useful prognostic information.