Serum Total Bilirubin as a Potential Biomarker in Chronic Obstructive Pulmonary Disease: A Correlation Study

Abstract

Background: The progressive inflammatory respiratory disorder known as chronic obstructive pulmonary disease (COPD) is a significant cause of morbidity and mortality globally. Though the association of bilirubin and COPD is still ambiguous, recent research suggests that bilirubin may protect against the onset of COPD. Objective: To determine the correlation between serum total bilirubin levels and chronic obstructive pulmonary disease. Methodology: This case-control study was conducted on 330 individuals from Lady Reading Hospital, Peshawar, aged ≥ 40 years, from 2019 to 2022. Their spirometry results divided participants into two groups: those with COPD (n = 165) and those without. Low (<0.6 mg/dL), intermediate (0.6-1.2 mg/dL), and high (>1.2 mg/dL) were the classifications given to the serum TB levels. Multivariate logistic regression was used to estimate COPD's adjusted odds ratios (ORs). Results: Those with COPD showed a significantly lower mean level of Total Serum Bilirubin in blood compared to controls (0.82 vs. 1.02mg/dL; p < 0.001). Low Total Bilirubin (TB) levels or concentrations by more than twofold odds for an individual having COPD (OR: 2.15; 95% CI: 1.24-3.73), while high TB levels conferred lower odds (OR: 0.52; 95% CI: 0.29-0.94) as compared to the intermediate group. Conclusion: A protective role of bilirubin, likely due to its anti-inflammatory and antioxidant properties, is provided by the association between lower levels of serum total bilirubin and an increased risk of COPD.