Abstract / Summary
Background: Chronic Obstructive Pulmonary Disease (COPD) is a chronic lung disease that has substantial morbidity and mortality worldwide. A widely used blood parameter, called Red Cell Distribution Width (RDW), has been proposed as a marker of inflammation and disease severity in COPD. Our objective is to find the correlation between RDW and COPD severity based on Global Initiative for Chronic Obstructive Lung Disease (GOLD) classification. Methods: This cross-sectional study was carried out in the Pulmonology Department, Khyber Teaching Hospital, Peshawar from 23-05-2025 to 03-04-2026. Non-probability consecutive sampling was used to recruit a total of 258 confirmed cases of COPD. Demographic and clinical information was taken. The severity of COPD was determined by the GOLD staging. RDW was determined by complete blood count (CBC) and classified as high (>14.5%) or normal (≤14.5%). The data were analyzed using SPSS-27 and the Chi-square test, One-way ANOVA and Pearson correlation coefficient with p<0.05 as significant value. Results: The mean age of the participants was 62.9±10.3 years and 68.2% were male. 57.8% of patients were found to have an elevated RDW. A majority of patients had severe to very severe disease (GOLD III-IV) (49.6%) and the majority were in GOLD II (35.7%) and III (31.4%). There was a strong correlation between RDW and COPD severity (p<0.001), as it rose from 26.3% in GOLD I to 83.0% in GOLD IV. Mean RDW rose significantly across stages (13.4±0.8% to 16.2±1.7%). A negative correlation was found between RDW and FEV₁ (% predicted) (r=-0.58, p<0.001). Conclusion: An increased RDW was significantly related to the severity of COPD and lung function, which indicated its potential to be a simple, low-cost biomarker for disease evaluation.