Red cell distribution width as a risk factor for postoperative pulmonary complications in chronic obstructive pulmonary disease: a retrospective exploratory cohort study

BACKGROUND Postoperative pulmonary complications (PPC) are a major concern in patients with chronic obstructive pulmonary disease (COPD). While ARISCAT is a useful risk-assessment tool, its effectiveness may vary in specific groups and high-workload settings. Red cell distribution width (RDW), an accessible biomarker of chronic inflammation and oxidative stress, offers potential prognostic value in several diseases. OBJECTIVE To investigate the association between RDW and PPC in a cohort of surgical patients with COPD and compare its potential predictive capacity with the ARISCAT score. METHODS This retrospective study included 92 adults with COPD undergoing noncardiac surgery. Associations between RDW (measured using a Sysmex XN-1000 analyser), ARISCAT, and PPC (three approaches: binary occurrence, complication count and two or more complications), were evaluated using bivariate, and multivariate regression models adjusted for atrial fibrillation (AF), surgery duration and thoracic surgery. Predictive performance was assessed via receiver-operating characteristic (ROC) curves, net reclassification improvement (NRI) and decision curve analysis (DCA). RESULTS Fifty-eight PPC occurred in 38 patients (41.3%). Median RDW was significantly higher in cases with complications (14.6 vs. 13.55, P = 0.004). RDW was independently associated with PPC count [incidence rate ratio (IRR) 1.16; 95% confidence interval (CI) 1.01 to 1.31; P = 0.038] and two or more PPC [odds ratio (OR) 1.84, 95% CI 1.21 to 3.02, P = 0.007], but not with binary occurrence ( P = 0.106). RDW showed no significant difference neither in ROC curves nor NRI, but demonstrated a higher clinical net benefit in DCA compared to ARISCAT. CONCLUSIONS Preoperative RDW was an independent risk factor for the frequency and severity (two or more) of PPC in COPD patients in our cohort. ROC, NRI and DCA analyses suggest predictive capacity of RDW for PPC and could serve as a tool for risk stratification. Further prospective, multicentre studies are needed to confirm these results and allow for their extrapolation.