Range of Risk Factor Levels, Risk Control, and Temporal Trends for Nephropathy and End-stage Kidney Disease in Patients With Type 1 and Type 2 Diabetes

Abstract

OBJECTIVE To investigate trends, optimal levels for cardiometabolic risk factors, and multifactorial risk control in diabetic nephropathy and end-stage kidney disease (ESKD) in patients with diabetes and matched control subjects. RESEARCH DESIGN AND METHODS This study included 701,622 patients with diabetes from the Swedish National Diabetes Register and 2,738,137 control subjects. Trends were analyzed with standardized incidence rates. Cox regression was used to assess excess risk, optimal risk factor levels, and risk according to the number of risk factors, in diabetes. RESULTS ESKD incidence among patients with and without diabetes initially declined until 2007 and increased thereafter, whereas diabetic nephropathy decreased throughout follow-up. In patients with diabetes, baseline values for glycated hemoglobin, systolic blood pressure (SBP), triglycerides, and BMI were associated with outcomes. Hazard ratio (HR) for ESKD for patients with type 2 diabetes who had all included risk factors at target was 1.60 (95% CI 1.49–1.71) compared with control subjects and for patients with type 1 diabetes 6.10 (95% CI 4.69–7.93). Risk for outcomes increased in a stepwise fashion for each risk factor not at target. Excess risk for ESKD in type 2 diabetes showed a HR of 2.32 (95% CI 2.30–2.35) and in type 1 diabetes 10.92 (95% CI 10.15–11.75), compared with control. CONCLUSIONS Incidence of diabetic nephropathy has declined substantially, whereas ESKD incidence has increased. Traditional and modifiable risk factors below target levels were associated with lower risks for outcomes, particularly notable for the causal risk factors of SBP and HbA1c, with potential implications for care.