Impact of chronic kidney disease definition on assessment of its incidence and risk factors in patients with newly diagnosed type 1 and type 2 diabetes in the UK: A cohort study using primary care data from the United Kingdom

AIM: To estimate the incidence and risk factors of chronic kidney disease (CKD) in patients with newly-diagnosed diabetes using different CKD definitions. METHODS: Using UK primary care data, patients with diabetes (type 1, 4691; type 2, 109,365) and no CKD were followed to identify newly-diagnosed CKD, classified by a broad and narrow CKD definition (to capture diabetes-induced CKD, termed diabetic kidney disease, DKD). Adjusted incidence rates of CKD/DKD were calculated, and risk factors identified using Cox regression. RESULTS: There were 404 CKD cases and 147 DKD cases among patients with type 1 diabetes (T1D), and 29,104 CKD cases, 9284 DKD cases among patients with type 2 diabetes (T2D). Adjusted incidence rates of CKD per 100 years were 5.4 (T1D) and 5.5 (T2D); for DKD they were 1.9 and 1.5, respectively. Risk factors for CKD/DKD were older age, high social deprivation, obesity, cardiovascular disease, hypertension and smoking. Poor glycaemic control in the year after diabetes diagnosis was a strong predictor of CKD/DKD occurrence beyond this first year, and a risk factor for CKD/DKD in T2D. CONCLUSIONS: CKD and DKD remain common in diabetics in the decade after diagnosis. Early prevention of T2D and aggressive treatment of risk factors is urgent.