Prospective Biopsy-Based Study of CKD of Unknown Etiology in Sri Lanka

Shuchi Anand,1 Maria E. Montez-Rath,1 Dinuka Adasooriya,2,3 Neelakanthi Ratnatunga,4 Neeraja Kambham,5 Abdool Wazil,2 Sulcohana Wijetunge,4 Zeid Badurdeen,3 Charaka Ratnayake,2 Nishamani Karunasena,2 Stephen L. Schensul,6 Penny Valhos,7 Lalarukh Haider,8 Vivek Bhalla,1 Adeera Levin,9 Paul H. Wise,10 Glenn M. Chertow,1 Michele Barry,11 Andrew Z. Fire,5 and Nishantha Nanayakkara2,3


1 Division of Nephrology and Departments of 5 Pathology, 10Pediatrics, and 11Medicine, Stanford University School of Medicine, Palo Alto, California; 2 Kandy Teaching Hospital, Kandy, Sri Lanka; 3 Center for Education Research and Training on Kidney Diseases, Faculty of Medicine and 4 Department of Pathology, University of Peradeniya, Kandy, Sri Lanka; 6 Department of Community Medicine and Health Care and 8 Division of Nephrology, University of Connecticut Health Center, Farmington, Connecticut; 7 Department of Marine Sciences, University of Connecticut, Groton, Connecticut; and 9 Division of Nephrology, University of British Columbia, Vancouver, British Columbia, Canada



Background and objectives

A kidney disease of unknown cause is common in Sri Lanka’s lowland (dry) region. Detailed clinical characterizations of patients with biopsy-proven disease are limited, and there is no current consensus on criteria for a noninvasive diagnosis.


Design, setting, participants, & measurements

We designed a prospective study in a major Sri Lankan hospital servicing endemic areas to ascertain pathologic and clinical characteristics of and assess risk factors for primary tubulointerstitial kidney disease. We used logistic regression to determine whether common clinical characteristics could be used to predict the presence of primary tubulointerstitial kidney disease on kidney biopsy.



From 600 new patients presenting to a tertiary nephrology clinic over the course of 1 year, 87 underwent kidney biopsy, and 43 (49%) had a biopsy diagnosis of primary tubulointerstitial kidney disease. On detailed biopsy review, 13 (30%) had evidence of moderate to severe active kidney disease, and six (15%) had evidence of moderate to severe chronic tubulointerstitial kidney disease. Patients with tubulointerstitial kidney disease were exclusively born in endemic provinces; 91% spent a majority of their lifespan there. They were more likely men and farmers (risk ratio, 2.0; 95% confidence interval, 1.2 to 2.9), and they were more likely to have used tobacco (risk ratio, 1.7; 95% confidence interval, 1.0 to 2.3) and well water (risk ratio, 1.5; 95% confidence interval, 1.1 to 2.0). Three clinical characteristics—age, urine dipstick for protein, and serum albumin—could predict likelihood of tubulointerstitial kidney disease on biopsy (model sensitivity of 79% and specificity of 84%). Patients referred for kidney biopsy despite comorbid diabetes or hypertension did not experience lower odds of tubulointerstitial kidney disease.



A primary tubulointerstitial kidney disease occurs commonly in specific regions of Sri Lanka with characteristic environmental and lifestyle exposures.


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