The impact of blood pressure variability and African Caribbean ethnicity on the progression of diabetic kidney disease in type 1 diabetes

Aims/hypothesis Blood pressure variability (BPV) is a risk factor for kidney disease progression in hypertension and type 2 diabetes; however, the role of BPV in kidney disease in type 1 diabetes is unknown. The aim of this study was therefore to determine whether BPV has an impact on kidney disease progression in an ethnically diverse cohort of people with type 1 diabetes. Methods We studied 3079 people (median age 36 [range 18–85] years; 50% female; 78.5% White, 10.9% African Caribbean, 4.5% Asian, 6.1% Other) with type 1 diabetes and baseline eGFR >45 ml/min per 1.73m 2 attending two university hospital clinics between 2004 and 2018. BPV was assessed using visit-adjusted standard deviation (adj-SD), CV and average real variability (ARV) for systolic blood pressure (SBP) and diastolic blood pressure (DBP). The primary endpoint was eGFR decline of ≥50% from baseline with final eGFR <30 ml/min per 1.73m 2 , with death as a competing risk. Results Over a 14 year period, 272 people (8.8%) reached the primary endpoint. All BPV metrics for SBP and DBP were significantly associated with the primary endpoint. ARVs of SBP and DBP and African Caribbean ethnicity emerged as risk factors in multivariable analyses, independent of traditional risk factors, including baseline blood pressure, eGFR, HbA 1c , albuminuria and mean blood pressure in the exposure window. The strongest association was observed for the ARV of SBP (HR 1.54, 95% CI 1.27, 1.87, p <0.001). Conclusions/interpretation In people with type 1 diabetes, SBP and DBP variability are associated with kidney disease progression. Further studies are needed to investigate if BPV is a modifiable risk factor for kidney disease progression.