SAT-251 DIFFERENCES IN PATIENTS BETWEEN CKD – CAUSE UNKNOWN AND THOSE WITH KNOWN CAUSES OF CKD: A COMPARISON FROM THE INDIAN CHRONIC KIDNEY DISEASE COHORT

Abstract

The cause of chronic kidney disease (CKD) cannot be ascertained in a substantial proportion of patients in developing countries. Whether there is a systematic difference between the characteristics of these patients and those with known causes of CKD is not known. We present differences in the baseline profile of subjects with CKD-cause unknown (CKD-CU) versus those with known causes of CKD who are enrolled in the ongoing, multicentric Indian Chronic Kidney Disease (ICKD) study in India. The ICKD study is an ongoing, nationwide, prospective cohort study of subjects with early stage CKD (stage G3 or proteinuria with stage G1-2) at 11 centres across India. CKD-CU was defined as CKD without any identifiable clinical cause for CKD in the absence of any structural abnormality. Baseline demographic and investigational characteristics between those with CKD-CU versus known causes of CKD were compared by univariate analysis. Out of 2930 subjects enrolled in the ICKD study till September 2018, 731 (25%) were assigned a diagnosis of CKD-CU. Edema, hypertension and proteinuria were present in 10.7%, 60.7% and 41.9% of those with CKD-CU, respectively and were significantly less common in this group (p=0.002 for edema, p<0.001 for both hypertension and proteinuria). Subjects in CKD-CU group were significantly more likely to be older, have a shorter duration of kidney disease, poor educational status, rural residence, lower monthly earnings, farming or unskilled occupations and occupational exposure to sand, dust, fields or animals (p<0.001 for each). CKD-CU group were significantly less likely to have family history of kidney disease (p=0.003), history of alternative drug use (p<0.001) and history of AKI (p<0.001). Amongst investigations, CKD-CU group had significantly higher serum creatinine (p<0.001), uric acid (p=0.012), alkaline phosphatase (p=0.001), total protein (p=0.002) and albumin (p=0.02) but lower serum calcium levels (p=0.012). No differences were observed in gender distribution, dietary (vegetarian) status or self-reported cardiovascular disease. The cause of CKD cannot be determined in a quarter of CKD patients presenting to hospitals. Most of these patients come from rural or poorer socio-economic classes, are less educated and more likely to have potential occupational exposure. These factors need detailed exploration as risk factors.