DIAGNOSTIC SIGNIFICANCE OF GLOMERULAR FILTRATION RATE ESTIMATED USING CREATININE AND CYSTATIN C IN CHRONIC OBSTRUCTIVE PULMONARY DISEASE

Abstract

Abstract. Objective. To assess the diagnostic value of glomerular filtration rate estimated from serum creatinine and cystatin C for detecting renal dysfunction in patients with chronic obstructive pulmonary disease (COPD). Materials and methods. The prospective study included 214 patients with moderate to very severe COPD (grades II–IV). Serum creatinine and cystatin C levels were measured. Estimated glomerular filtration rate (eGFR) was calculated using the CKD-EPI 2021 creatinine equation and the CKD-EPI 2012 cystatin C equation. Renal filtration impairment was defined as eGFR<60 mL/min/1.73 m². Results. Creatinine-based eGFR<60 mL/min/1.73 m² was identified in 29 patients (13.6%), whereas cystatin C-based eGFR<60 mL/min/1.73 m² was detected in 148 patients (69.2%). Serum cystatin C levels were significantly higher in patients with reduced eGFR across COPD grades II, III and IV (p<0.001). Significant differences in serum creatinine and creatininebased eGFR were observed predominantly in patients with grade III COPD (p<0.05). Conclusion. Creatinine-based eGFR remains an important conventional marker for assessing clinically significant impairment of renal filtration. Cystatin C-based eGFR expands the ability to detect reduced renal function in patients with COPD, including those with relatively preserved creatinine-based indices.