Red Cell Distribution Width at Hospital Discharge and Out-of Hospital Outcomes in Critically Ill Non-Cardiac Vascular Surgery Patients

Abstract

Objective Red cell distribution width (RDW) is associated with mortality and bloodstream infection risk in the critically ill. In vascular surgery patients surviving critical care it is not known if RDW can predict subsequent risk of all-cause mortality following hospital discharge. We hypothesized that an increase in RDW at hospital discharge in vascular surgery patients who received critical care would be associated with increased mortality following hospital discharge. Design, setting, and participants We performed a two-center observational cohort study of critically ill non-cardiac vascular surgery patients surviving admission 18 years or older treated between November, 1997, and December 2012 in Boston, Massachusetts. Exposures RDW measured within 24 hours of hospital discharge and categorized a priori as ≤13.3%, 13.3-14.0%, 14.0-14.7%, 14.7-15.8%, >15.8%. Main outcomes and measures The primary outcome was all cause mortality in the 90 days following hospital discharge. Results The cohort included 4,715 patients (male 58%; white 83%; mean age 62.9 years). 90 and 365-day post discharge mortality was 7.5% and 14.4% respectively. In the cohort, 47.3% were discharged to a care facility and 14.8% of patients were readmitted within 30 days. After adjustment for age, gender, race, Deyo-Charlson comorbidity Index, patient type, acute organ failures, prior vascular surgery and vascular surgery category, patients with a discharge RDW 14.7-15.8% or >15.8% have an adjusted OR of 90-day post discharge mortality of 2.52 (95%CI, 1.29-4.90; P = 0.007) or 5.13 (95%CI, 2.70-9.75; P 15.8% group was 1.52 (95%CI, 1.12-2.07; P = 0.007) relative to patients with a discharge RDW ≤13.3%. Similar adjusted discharge RDW-outcome associations are present at 365 days following hospital discharge and for discharge to a care facility. Conclusions In critically ill vascular surgery patients who survive hospitalization, an elevated RDW at hospital discharge is a strong predictor of subsequent mortality, hospital readmission and placement in a care facility. Patients with elevated RDW are at high risk for adverse out of hospital outcomes and may benefit from closer post discharge follow-up and higher intensity rehabilitation.