To Predict the Association of Blood Urea Nitrogen to Creatinine Ratio With Sarcopenia in Patients With Chronic Obstructive Pulmonary Disease

Background: Chronic Obstructive Pulmonary Disease (COPD) is a major global health burden, often complicated by sarcopenia, a condition characterized by progressive muscle mass and strength loss. The blood urea nitrogen (BUN) to creatinine ratio, typically used to assess renal function, may serve as a marker for muscle wasting in COPD patients. This study investigates the association between the BUN/creatinine ratio and sarcopenia in COPD patients, alongside pulmonary function and inflammatory markers. Methods: A hospital-based, cross-sectional study was conducted at Sawai Man Singh Medical College, Jaipur, India, from March 2023 to April 2024. A total of 120 COPD patients (aged >40 years, diagnosed per GOLD guidelines) were assessed. Sarcopenia was evaluated using the SARC-CaLF score, with scores ≥11 indicating sarcopenia. BUN and creatinine levels, pulmonary function tests (FEV1, FVC, FEV1/FVC, PaO2, PaCO2, SpO2). Statistical analyses included Chi-square tests, t-tests, and ANOVA to explore associations. Results: Sarcopenia was present in 33.3% of participants, with higher prevalence in severe (30.0%) and very severe (47.5%) COPD cases (p=0.003). The BUN/creatinine ratio was significantly higher in sarcopenic patients (29.25 ± 14.91 vs. 23.77 ± 10.26, p=0.030), driven by elevated BUN levels (16.79 ± 4.11 mg/dL vs. 15.14 ± 4.22 mg/dL, p=0.044). Sarcopenic patients exhibited poorer pulmonary function (lower FEV1, FVC, FEV1/FVC, PaO2, SpO2; higher PaCO2, all p<0.05). No significant associations were found with sex or sociodemographic status. Conclusion: The BUN/creatinine ratio is significantly associated with sarcopenia in COPD patients, particularly in severe cases, and correlates with systemic inflammation and impaired pulmonary function.