Correlation of survival and stage at presentaion,in CKDu of Sri Lanka – a single center retrospective study

Abstract

Introduction Chronic kidney disease of unknown etiology (CKD-u) is a major health burden in Sri Lanka. Along with uncertainties on etiology there are many other unexplored aspects in this mysterious disease including natural history, morbidity and mortality. Girandurukotte, located in Uva province of Sri Lanka, was identified as an endemic area in 2006 and henceforth patients diagnosed as CKD-u were registered and followed up at a specialized renal clinic. Our aim was to analyze the correlation of survival of CKD-u patients with chronic kidney disease (CKD) stage at initial presentation and to determine related lifestyle factors. Method This is a retrospective study. Recorded and available data of all CKD-u patients (n=379) registered and followed up in Girandurukotte renal clinic, during the period of 2005 to 2014, was analyzed. The disease was categorized into five clinical stages, according to the Kidney Disease Outcomes Quality Initiative (KDOQI) criteria based on the estimated glomerular filtration rate. Patients were observed for survival up to 2014 (maximum follow up period was 158 months). Data was analyzed using R statistical software. Discussion A prospective study carried out in Medawachchiya, Sri Lanka found that family history of chronic renal disease and history of snake bite were significant predictors for CKD-u (Wanigasooriya et al, 2007), but according to our study in Girandurukotte, they are not significant risk factors. Results Out of 379 (270 males and 109 females), majority were in stage 3 on presentation. Mean age at presentation was 43 years (SD-6.5). All of them were Sinhalese in ethnicity and belonged to rural communities. 10 patients were lost to follow up and 15 deaths were recorded during the study period. Stage 1 had the highest survival rate, which progressively decreased with advancing clinical stages. Only gender showed a significant effect (p= 0.096, α=0.10) on CKD-u. Males had 2.3 times risk for CKD-u than females. Females had higher survival rate than males at all stages Among males, smoking had a significant effect on CKD-u. (p=0.0924, α=0.10). Smoking males have 2.57 times risk for CKD-u, than non-smoking males. Conclusion This study confirmed that males are more prone to get CKD-u and females have better survival rates. Most patients are presented at late stages (stage 3 and 4) and stage 1 has the highest survival rate among all stages, claiming that early identification of the disease is vital for better outcome. Smoking habit among males has a significant adverse effect on survival.