Why is there so much end-stage renal failure of undetermined cause in UK Indo-Asians?

Abstract

There is a high incidence of end-stage renal failure (ESRF) of undetermined cause in the Indo-Asian population of the UK. We studied patients presenting from the district of Brent and Harrow, which has a large Indo-Asian community, and whose renal services are largely provided by our centre. The diagnosis and ethnicity of patients starting renal replacement therapy and/or undergoing renal biopsy were collated. The incidences of ESRF, rates of renal biopsy and underlying diagnoses were calculated for Indo-Asians and Caucasians. Requirement for renal replacement therapy in Indo-Asians presenting to our centre from Brent and Harrow was 221/10(6)/year; no underlying diagnosis was identified in 77/10(6)/year. Renal biopsy rate in these patients was 456/10(6)/year, and the diagnostic categories significantly over-represented compared to Caucasians were: hypertension and ischaemia, focal segmental glomerulosclerosis (FSGS), idiopathic interstitial nephritis (IIN), diabetic nephropathy, minor glomerular abnormality, lupus nephritis and non-specific advanced chronic renal disease (p<0.001). The first three of these had a combined incidence of 135/10(6)/year in Indo-Asians and 31/10(6)/year in Caucasians. ESRF of undetermined cause is common in UK Indo-Asians, as is requirement for renal biopsy. Hypertension with ischaemia, FSGS and IIN are over-represented in the Indo-Asian population, and should be targeted for early diagnosis and treatment in this group.

Microalbuminuria and Coronary Heart Disease Risk in an Ethnically Diverse UK Population

“…Our findings of similar AER and prevalence of MA in UK South Asians and Europeans confirm those of UKPDS (17) in people with type 2 diabetes but do not correspond with the high rates of ESRD in South Asians (28) or the findings of Mather et al (14) and Fischbacher et al (15). The last two studies were smaller than ours.…”

“…However, in the United Kingdom, in those with diabetes, South Asians are known to have a 13-fold increase in risk for ESRD compared with Europeans (30), and in those without diabetes, South Asians have a 3.5-fold increase in risk (28,30,31). A large US primary care study of people with diabetes found that those of Asian origin without hypertension had two-fold prevalence of microalbuminuria (32).…”

“…The low risk for microalbuminuria is more remarkable, especially given the greater risks for ESRD. However, although diabetes contributes to some of the excess risk for ESRD, a greater prevalence of idiopathic interstitial nephritis is also observed (28). These patients present at late stages of disease with shrunken kidneys, as early stages are asymptomatic, and may not be associated with albuminuria to the same extent as diabetic nephropathy.…”

Ethnicity and renal disease: questions and challenges

“…A recent renal biopsy study reports increases in most patterns of parenchymal renal disease, including chronic interstitial nephritis of undetermined cause. 6 There is a marked excess of tuberculosis among South Asians with renal failure; anecdotal evidence suggests tuberculosis as a possible aetiological agent for this non-specific chronic renal disease, with occasional impressive improvements in renal function in response to anti-tuberculous therapy even in the absence of positive microbiological evidence or characteristic renal histology. But cause and effect have not been systematically confirmed.…”

Genetics of diabetes complications

“…This different genetic heritage should be reflected, in the case of diabetes complications, in different rates of complications. There are now numerous studies that suggest the incidence of renal complications of diabetes is significantly different in diverse racial or ethnic groups even when they reside in the same country [8][9][10][11][15][16][17][18][19].…”