<b>Correlation of Serum Creatinine, Urea, and Hemoglobin Level in Chronic Kidney Disease</b>

Background: Chronic kidney disease (CKD) is a global health concern characterized by progressive renal function decline and is commonly associated with anemia. Although creatinine and urea are established biomarkers of CKD, their correlation with hemoglobin levels remains underexplored in local populations, limiting early detection of anemia in clinical practice. Objective: This study aimed to assess the correlation between serum creatinine, urea, and hemoglobin levels in patients with CKD, and to determine the extent to which anemia is associated with disease severity. Methods: A cross-sectional correlational study was conducted among 170 confirmed CKD patients aged ≥18 years at Chaudhry Muhammad Akram Teaching and Research Hospital, Lahore, Pakistan, from October 2024 to March 2025. Participants with acute renal failure, recent blood transfusion, or unrelated hematologic disorders were excluded. Blood samples were analyzed for serum creatinine, urea, hemoglobin, and eGFR using standardized protocols with Mindray analyzers. Ethical approval was obtained in compliance with the Declaration of Helsinki. Pearson correlation analysis was performed using SPSS version 25.0. Results: A moderate to strong inverse correlation was found between hemoglobin and both serum creatinine (r = -0.626, p < 0.001) and urea (r = -0.499, p < 0.001). A strong positive correlation existed between creatinine and urea (r = 0.719, p < 0.001). Hemoglobin levels also declined with advancing CKD stage (R² = 0.528) and were positively associated with eGFR (r = 0.780, p < 0.001), highlighting the clinical linkage between renal impairment and anemia severity. Conclusion: Anemia in CKD patients is significantly associated with elevated serum creatinine and urea, and declining eGFR. These correlations support routine monitoring of renal and hematologic parameters to enable early detection and management of anemia, thereby improving patient outcomes.