Volume 34 Number 3 (2025)
Association of Air Flow Limitation Severity with eGFR in Stable COPD Patients: A Cross-Sectional Study
Farhana T1 , Qayyum MA2 , Hossain MA3 , Hossain SS4 , Shamsuzzaman S5 , Hossain N6 , Rahman MM7 , Reshma SS8 , Khan AI9 , Bonny BP10 , Debnath D11 , Rahman M12
Mymensingh Med J 2025 Jul; 34 (3): 887-896
PMID: 40583683
Abstract
Chronic obstructive pulmonary disease (COPD) is primarily a lung disease, but its consequences also affect other vital organs. Forced expiratory volume in one second (FEV1), a basic spirometry finding along with others (Predicted FEV1% and FVC), is essential for COPD diagnosis and severity analysis. Renal functional evaluation is essential, in addition to other systemic evaluations. Its evaluation is important because drugs used for the treatment of COPD are mostly excreted through the kidneys, which may cause its impairment. The estimated GFR (eGFR) by the modification of the diet in renal disease (MDRD) study group equation can approximate the actual GFR. This study aimed to elicit the association between airflow limitation severity and eGFR in stable COPD patients. This cross-sectional observational study included 95 patients with stable COPD who presented at the NIDCH between June 2018 and June 2019. The mean spirometry indices were compared with the eGFR-based groups (eGFR ≥60 mL/min/1.73 m2 and eGFR <60 mL/min/1.73 m2). Correlation test was done to elicit the association of FEV1 with eGFR. In addition, the prediction capability of eGFR along with other clinically relevant effector variables for FEV1 was analyzed. FEV1 was strongly correlated with eGFR (r=0.754, p<0.001). Predicted FEV1% and FVC had moderate correlations with eGFR (r=0.646, p<0.001 and r=0.691, p<0.001, respectively), whereas FEV1/FVC had weak correlations with eGFR (r=0.440, p<0.001). eGFR showed good prediction capability (β=-0.176, p<0.001) among other clinically relevant effector variables (age, sex, smoking, exacerbation history, mMRC grade, CAT score and BMI). All spirometry indices (FEV1, PFEV1%, FVC and FEV1/FVC) were correlated with eGFR. FEV1 was strongly correlated (positively) with eGFR and showed linear relation. Furthermore, eGFR had a good predictive capability for FEV1. FEV1 in stable COPD patients can be used as a predictor of renal function (eGFR), enabling early detection of renal functional impairment. Based on this, further evaluation, preventive measures or modifications in treatment strategy could be adopted accordingly.
Keywords: Air flow limitation severity, Stable COPD, FEV1, eGFR
- Medical Officer