Can race and/or ethnicity determine the progression of chronic kidney disease (CKD) in diabetics? Apparently they can.

A 10-year community-based study in London aimed to determine ethnic differences in adults with type 2 diabetes mellitus (T2DM) regarding:

• rate of estimated glomerular filtration rate (eGFR) decline
• risk of end-stage renal failure (ESRF) and
• risk of death

Appearing in the British Medical Journal, the investigators also aimed to identify predictors of rapid kidney function decline and failure, which is crucial for optimal disease and symptom management.*

What They Did

The study examined 6,274 participants of white, South Asian, or black race/ethnicity between the ages of 25 and 84, with diagnoses of both CKD and T2DM, and who were free from ESRF/dialysis at the start of the study (baseline).

Ethnicity was further broken down into:

• black subgroups of African and Caribbean
• South Asian subgroups of Indian and Pakistani

Other variables included:

• age
• systolic blood pressure
• HbA1c (average blood sugar level for the past 2-3 months)
• proteinuria (increased levels of protein in the urine)
• diagnosed cardiovascular disease (CVD)

What They Found

At baseline, the South Asian and black groups had a longer duration of diabetes and higher HbA1c values than the white group. Baseline eGFR was comparable between ethnic groups, though proteinuria and hypertension were highest in the black group and lowest in the South Asian group.

• Odds of rapid eGFR decline were significantly higher in the African, Caribbean and Bangladeshi groups than in the white group, and were highest for the African group.
• Odds were double for individuals aged 25–54, and significantly increased (by 38%) for those aged 55–64.
• Proteinuria and elevated blood pressure were linked with higher odds, independently and in combination, the latter especially for the Bangladeshi group.
• Odds were significantly higher when cardiovascular disease was present at baseline. 

In summary, increased odds of rapid progression were associated with:

• Bangladeshi ethnicity
• hypertension
• proteinuria
• diabetes duration
• cardiovascular disease

The risk of ESRF was highest in the black groups, while the risk of death was significantly lower in the South Asian group than in the white group despite the high odds for rapid decline in the South Asian group. The risks of death for the white and black groups were similar.

Along with other predictors, ethnic differences in CKD progression among diabetics included the following:

• Odds of rapid renal decline were higher for people of Bangladeshi, African, and Caribbean ethnicity who had hypertension, proteinuria, cardiovascular disease, and increasing duration of diabetes.
• Risk of developing ESRF was highest in the black group.
• Risk of death from any cause was 29% lower in the South Asian group than in the white group.
• Rapid CKD progression was more frequent in diabetics under the age of 65. 

The study authors recommended continued research in these areas.

Refer to the full article for more information.

*Mathur, R.; Dreyer,G.; Yaqoob, M.; Hull, S. (2018, March 27). Ethnic differences in the progression of chronic kidney disease and risk of death in a UK diabetic population: an observational cohort study. BMJ Open. [Epub].