Risk of Kidney Decline in T1D Heightened for People of African Caribbean Ethnicity

Janaka Karalliedde, MBBS, PhD, FRCP, FHEA

Data from an analysis of an ethnically diverse cohort of more than 5000 people with type 1 diabetes is raising a red flag over an apparent increase in risk of developing chronic kidney disease among people of African Caribbean heritage with type 1 diabetes.

An analysis aimed at identifying risk factors for kidney function decline among people with type 1 diabetes in southeast London who received care from 2004-2018, results of the study suggest patients with African Caribbean ethnicity had a 57% greater risk of experiencing an eGFR decline of 50% or greater from baseline visit, with the incidence rate of such a decline in eGFR doubled in this patient population compared with non-African Caribbean people.

“Diabetes-related kidney failure is devastating for people affected and their families. This is the first study in type 1 diabetes to describe the impact of ethnicity on kidney function loss. We observed that African-Caribbean people with type 1 diabetes are at nearly 60% higher risk of losing more than half of their kidney function and that this loss also occurs faster. Further studies are needed to study and understand the exact reasons for this increased risk of kidney disease in African-Caribbean people with type 1 diabetes,” said Janaka Karalliedde, MBBS, PhD, FRCP, FHEA, a clinical senior lecturer in the School of Cardiovascular Medicine and Sciences at King's College London and a consultant in Diabetes, Endocrinology, and Internal medicine at Guy's and St Thomas' Hospital London, in a statement.

Although management of kidney disease in type 2 diabetes has become a main point of discussion across multiple specialties in recent years, less research and emphasis has been placed on identifying , particularly among minority patient populations. In what investigators call one of the largest studies of it its kind, the King’s College London-led team designed their study with the intent of identifying demographic and clinical risk factors for kidney decline in people with type 1 diabetes.

Data for the study was obtained from patients who attended primary care and eye screenings in southeast London between 2004-2018. Of note, 6368 individuals were originally identified for inclusion, but 1107 were excluded based on pregnancy, documented history of nondiabetic kidney disease on hospital records, or a baseline eGFR less than 45 mL/min/1.73m2.

The final analytic cohort of 5261 individuals had a median age of 34 (IQR, 26 to 46), median follow-up of 8 years, median duration of diabetes of 11 (IQR, 2 to 22) years, and 49.3% were male. Investigators noted 80% of people in the study were diagnosed with type 1 diabetes prior to the age of 40 years. The majority of individuals (77.8%) identified as Caucasian, followed by African Caribbean (13.4%), Asian (2.9%), and other (5.9%).

The primary outcome of interest for the study was an eGFR decline of 50% or greater from baseline with a final eGFR below 30 mL/min/1.73m2. Investigators pointed out eGFR was calculated using the Chronic Kidney Disease Epidemiology Collaboration equation, with correction for African Caribbean ethnicity where applicable.

During the follow-up period, 5% (n=263) of the 5261 patients included in the study achieved the primary outcome of interest. Initial analysis indicated patients who experienced the primary outcome were more likely to be of African Caribbean ethnicity, older, have a longer duration of diabetes, higher systolic blood pressure and HbA1c, more prevalent retinopathy, and higher albuminuria (all P < 0.05). In adjusted analyses, being of African Caribbean ethnicity was associated with a significant increase in risk of experiencing the primary outcome (HR, 1.57 [95% CI, 1.19-2.08]; P <.01). Further analysis suggested the overall incidence rate in African Caribbean people was more than double than the observed incidence rate for non–African Caribbean people (16 vs 7.7 per 1000 patient-years, P <.001). Investigators highlighted a similar trend was observed for African Caribbean ethnicity when assessing declines in eGFR of 30% or greater and 40% or greater as secondary outcomes.

This study, “African Caribbean Ethnicity Is an Independent Predictor of Significant Decline in Kidney Function in People With Type 1 Diabetes,” was published in Diabetes Care.