Risk factors for development and progression of diabetic kidney disease and treatment patterns among diabetic siblings of patients with diabetic kidney disease

Background: Diabetic siblings of patients with treated kidney failure from diabetic kidney disease are at a 5-fold increased risk of future kidney failure. The objective of this study is to define risk factors for kidney disease, clinical features, and treatment patterns in diabetic siblings of patients with diabetes with diabetic kidney disease. Study Design: Cross-sectional analysis using data collected from diabetic siblings of patients with diabetic kidney disease. Setting & Participants: 295 diabetic siblings with mean diabetes duration of 15 years from within a 400-mile radius of Cleveland, OR or Winston-Salem, NC. Predictors: Demographic data, diabetes duration, blood pressure (BP), access to health care, and diabetes control. Outcomes: Albuminuria (defined as urinary album in-creatinine ratio >= 30 mg/g, with microalbuminuria with albumin of 30 to 300 mg/g and macroalbuminuria with albumin > 300 mg/g), renal function. Measurements: BP, urinary albumin-creatinine ratio, serum creatinine, glycosylated hemoglobin (HbA(1c)), estimated glomerular filtration rate. Results: Mean diabetes duration was 14.6 +/- 10.6 years. Albuminuria was present in 46% of participants. In individuals with diabetes duration of 11 to 15 years, 25% had microalbuminuria and 18.2% had macroalbuminuria. Despite a positive family history and a high prevalence of albuminuria, only 35.3% of participants had a target systolic BP less than 130 mm Hg. HbA(1c) levels were 7% or greater in 57.4% of patients, and 26.4% of participants were smokers. Only 58% of patients received angiotensin-converting enzyme inhibitors or receptor blockers. In microalbuminuric participants, HbA(1c), level was greater than 10% in 28.6% versus 13.3% in those without albuminuria (P = 0.02). Limitations: A control group of diabetic siblings without a family history of diabetic kidney disease was not obtained. Conclusions: Diabetic siblings of patients with diabetic kidney disease have a high prevalence of albuminuria and poor glycemic and BP control. Targeting these high-risk individuals for interventions to improve their BP and blood glucose control might prevent or slow the progression of diabetic kidney disease.