Biologic and social factors predict incident kidney disease in type 1 diabetes: Results from the T1D exchange clinic network

Aims: Diabetic kidney disease (DKD) is a major complication of type 1 diabetes (T1D). To better understand the development of DKD in modern clinical practice, we evaluated risk factors in participants from the T1D Exchange Registry who completed 5-years of longitudinal follow-up. Methods: Participants had T1D duration ≥ 1 year, age ≥ 10 years, eGFR ≥ 60 ml/min and no albuminuria at enrollment, and at least two serum creatinine and urine albumin measurements recorded during follow-up. Adverse kidney outcomes were defined as eGFR ≪ 60 ml/min and/or albuminuria (ALB) defined by as two consecutive albumin/creatinine ratios or two out of the past three measurements ≫ 30 μg/mg at any follow-up data collection. Associations of baseline characteristics with adverse kidney outcomes were assessed. Results: Among 3940 participants (mean age 41 ± 15 yrs, T1D duration 21 ± 13 yrs), 653 (16.6%) experienced an adverse kidney outcome: 268 (6.8%) experienced incident ALB only, 322 (8.2%) had eGFR decline to ≪60 ml/min without ALB, and 63 (1.6%) experienced eGFR ≪ 60 ml/min with ALB. In a multivariable analysis, higher HbA1c, higher SBP, lower DBP, older age and lower education level were associated with the development of adverse kidney outcomes (all p values ≤ 0.03). Conclusions: Improving modifiable risk factors, including glucose and blood pressure control, remain important to reduce the risk of DKD in T1D.