Prevalence of Chronic Kidney Disease in an Urban Population ST De Silva1,2, DM Gamage1, WSAA Yasith Udara1 1Department of Medicine, Faculty of Medicine, University of Kelaniya 2University Medical Unit, Colombo North Teaching Hospital, Ragama

INTRODUCTION Prevalence of chronic kidney disease (CKD) is increasing worldwide – population prevalence is >10% >50% in high-risk subpopulations* Median global prevalence is estimated to be – 7.2% in persons aged ≥30 years 23.4% - 35.8% in persons aged ≥64 years** Due to increasing incidence of Diabetes Mellitus (DM) and Hypertension (HPT) in aging populations * Eckardt et al. Evolving importance of kidney disease: from subspecialty to global health burden. Lancet. 2013 July:382(9887):158-169 **Zhang et al. Prevalence of chronic kidney disease in population-based studies: Systematic review. BMC Public Health 2008, 8:117

Situation in Sri Lanka DM and HPT affect many Sri Lankan adults Prevalence of DM in adults is 10.3%* Prevalence of HPT is 18.8% for men and 19.3% for women (in 4 provinces)** *Katulanda et al. Prevalence and projections of diabetes and pre-diabetes in adults in Sri Lanka. Diabetes Medicine 2008 Sep;25(9):1062-9 **Wijewardene et al. Prevalence of hypertension, diabetes and obesity: baseline findings of a population based survey in four provinces in Sri Lanka. CMJ 2005 Jun;50(2):62-70.

CKD in Sri Lanka Data on population prevalence of CKD in Sri Lanka is scarce Published studies have mainly looked at hospital prevalence rates* *Athuraliya et al. Prevalence of chronic kidney disease in two tertiary care hospitals: high proportion of cases with uncertain aetiology. CMJ 2009 Mar;54(1):23-5 *Gooneratne et al Epidemiology of chronic kidney disease in a Sri Lankan population. International Journal of Diabetes in Developing Countries. 2008 Apr;28(2):60-4 *Wijewickrama et al. Epidemiology of chronic kidney disease in a Sri Lankan population: experience of a tertiary care center. Saudi Journal of Kidney Disease & Transplantation. 2011 Nov; 22(6):1289-93

CKDu CKD of uncertain aetiology (CKDu) in the some provinces of Sri Lanka receives much attention High mortality & morbidity

CKDu Conflicting reports on CKDu prevalence rates WHO – 15.3%* Previous estimates ranged from 2 - 8.57%** *Investigation & evaluation of chronic kidney disease of uncertain aetiology in Sri Lanka – Final Report WHO 2013 ** Athuraliya et at. Uncertain aetiologies of proteinuric chronic kidney disease in rural Sri Lanka. Kidney lnternational 2011;80(11);212-1221

METHODOLOGY Ragama Health Study (RHS) - ongoing community based research project of the Ragama MOH area RHS has 3012 recruited adult participants Randomly selected subjects from RHS cohort Informed written consent Interviewer-administered questionnaire

METHODOLOGY Serum creatinine tested* Estimated glomerular filtration rate (eGFR) calculated using the CKD-EPI formula CKD defined as eGFR <60ml/min/1.73m2 (≥Stage III in KDIGO/KDOQI classification)** *JAFFE method – all tests done at same laboratory **Levey et al. The definition, classification, and prognosis of chronic kidney disease. Kidney International 2011 July; 80(1): 17-28

RESULTS 301 subjects 178/301 (59.1%) were female

Age Distribution Mean age - 57.5 years (range 40 - 73 years)

Distribution of CKD Stages 42/301 (14%) had eGFR <60ml/min/1.73m2 34/42 (81%) were in CKD Stage IIIA

Distribution of CKD Stages

Comparison of CKD & Non-CKD

Subjects with CKD were, significantly older than 60 years (p<0.000) more likely to have – type 2 DM (p<0.012) HPT (p<0.000) IHD (p<0.031) hyperlipidaemia (p<0.023) compared to those without CKD

Limitations Urinary albumin to creatinine ratio (ACR) was not assessed due to cost constraints Formulae used to calculate eGFR are known to systematically underestimate GFR CKD-EPI performs better at higher GFR values than MDRD equation, but performance in elderly is uncertain

CONCLUSIONS CKD prevalence in our sample (14%) is similar to the prevalence of CKDu in Rajarata (15.3% WHO 2013) As expected, DM and HPT were the primary associated co-morbidities

CONCLUSIONS Most subjects with CKD were in stage IIIA- when early recognition and better control of co-morbid factors are known to retard progression CKD is under-recognized in Sri Lanka – large population-based studies are needed to better understand the size of the problem and implement preventive strategies  

Acknowledgements This study was carried out with the assistance of a WHO research grant provided to the Faculty of Medicine, University of Kelaniya Laboratory services were provided at a concessionary rate by Asiri Hospital Laboratory Services