Cross-sectional Study on Hematological Variation Associated With Advance Chronic Kidney Disease (CKD) in a CKDu Endemic Area in Sri Lanka

Abstract

A cross-sectional study was undertaken to investigate the etiology and disease progression in terms of CKD (chronic kidney disease)-initiation risk factors (IRF) and hematology in Nachchaduwa, a CKDu (CKD of unknown etiology)-endemic area in North Central Province of Sri Lanka. Whole blood, spot urine and risk factor history were obtained following informed consent from all medically confirmed CKD/CKDu cases in the area. CKDu was substantiated when medically accepted IRFs did not exist prior to CKD diagnosis. The disease progression stage (G1-G5) was established by kidney dysfunction markers, eGFR (MDRD, and CKD-EPI-sCr) and UACR using serum creatinine (sCr), urine creatinine (uCr) and urine (uAlb) measured in the study. Hematology variables were compared between early (G2-G3b) and advance (G4-G5) stages to reveal changes over disease progression and assessed for linear associations to disease progression in terms of kidney dysfunction markers and renal outcomes. Multivariate dendrogram and principal component analyses were utilized to study inter-variable relations. The results showed that advance disease (G4-G5) in Nachchaduwa had significantly declined RBC counts and RDW-CV, amid unchanged MCV, MCH, MCHC, hematocrit and total hemoglobin suggesting predominantly normocytic anemia. RBC depletion was further evident in its positive associations to eGFRs, and negative association to sCr (p<0.05, rho stronger than ±0.45). Multivariate analyses revealed that RDW-CV was following the decreasing eGFRs and uCr over disease progression. Results showed the potential utility of erythrocyte count and RDW-CV as markers of advance disease in CKDu endemic areas of Sri Lanka. IRF distribution in Nachchaduwa pointed to a minor fraction of unknown etiology among total CKD, and the major IRFs that led to chronic renal failure did not include Diabetes Mellitus.