Prevalence of chronic kidney disease in South Asian and Black minorities: findings from a population based screening study in London, UK
========================================================================================================================================

* P. Roderick
* L. Lightstone
* S. Harris
* M. Lapsley
* M. Dockrell
* E. Lim
* J. Chambers
* J. S. Kooner

## Background

People of both South Asian and Black ethnic origin have 3–4 fold higher rates of acceptance onto renal replacement therapy than Caucasians in the UK. They are known to have a higher prevalence of type 2 diabetes and Blacks also have a higher prevalence of hypertension but little is known about the comparative prevalence of chronic kidney disease (CKD) in these ethnic groups.

## Objective

To investigate the prevalence of CKD in Blacks and south Asians compared to Caucasians.

## Methods

Cross sectional study based on screening all adults registered with over 50 general practices aged 35–74 in a multiethnic area in West London, UK from 2002–7. Baseline assessment included renal function (serum creatinine converted to estimated glomerular filtration rate using 4 variable MDRD equations) and single urinary albumin: creatinine ratio (ACR) from 2004. Logistic regression was used to model adjusted odds ratios of low eGFR (<60 and <45 ml/min/1.73 m2) indicative of stage 3–5 and stage 3b–5 CKD respectively, by ethnic group separately by gender, with Caucasians as reference group.

## Results

Response rate to screening was 60%. Of 31 507 participants, 19 769 (63%) were South Asian (SA), 9222 (29%) Caucasian and 2516 (8%) Black (B). All had eGFR calculable. Age adjusted prevalence of eGFR <60 was 1.29 (1.10 to 1.51) in SA males, 0.87 (0.62 to 1.23) in B males, 0.74 (0.63 to 0.89) in SA females and 0.35 (0.23 to 0.54) in B females. Corresponding figures for eGFR <45 were SA males 1.89 (1.38 to 2.58) B males 1.64 (0.93 to 2.89) SA females 0.92 (0.56 to 1.34) and B females 0.50 (0.21 to 1.18). Full adjustment for prevalent diabetes, hypertension, vascular disease and social deprivation did not alter these patterns.

## Conclusion

Despite a higher prevalence of underlying risk factors such as Type 2 diabetes, CKD prevalence of stage 3–5 (eGFR<60) was generally lower in both ethnic groups except South Asian males. However more advanced CKD (eGFR <45) in men was commoner in both ethnic groups suggesting they are more susceptible to progressive kidney damage. Urinary albumin excretion, an important marker of kidney damage, is being measured currently and data will be presented. The reasons for the gender difference in kidney function require further exploration.