Clinical features and risk factors of renal damage in elderly and non-elderly patients with type 2 diabetes mellitus

Abstract

To investigate the clinical features and risk factors of renal damage in the elderly and non-elderly patients with type 2 diabetes mellitus. The data were collected from a survey of 10-year retrospective study of chronic complications of hospitalized type 2 diabetics organized by Chinese Diabetes Society. A total of 1351 patients of type 2 diabetes were selected and divided into an elderly group (>or=60 year) and a non-elderly group (<60 year). The patients were also divided into three groups according to urinary albumin excretion rate (AER): normoalbuminuria group (AER<30 mg/24 h), microalbuminuria group (30<or=AER<300 mg/24 h) and macroalbuminuria group (AER>or=300 mg/24 h). eGFR was estimated by the equation from the MDRD study. Clinical and laboratory parameters of all patients were analyzed. (1) The proportions of renal insufficiency in both normoalbuminuria and microalbuminuria groups of type 2 diabetes in the elderly patients were significantly higher than those in the non-elderly patients (26.7% vs 15.8%, P<0.01; 30.5% vs 21.3%, P<0.05 respectively); (2) in type 2 diabetic patients with renal insufficiency and normoalbuminuria, the diabetes duration (7.7 vs 3.8 years), systolic blood pressure [(146+/-24) mm Hg vs (134+/-23) mm Hg], diastolic blood pressure [(84+/-13) mm Hg vs (80+/-11) mm Hg], proportion of hypertension (37.8% vs 21.1%), diabetic retinopathy (34.1% vs 23.9%), cardiovascular diseases (31.6% vs 11.3%) and cerebrovascular disease (24.4% vs 9.9%) were significantly higher in the elderly group than in the non-elderly group (P<0.05 or 0.01); (3) multiple logistic regression analysis revealed that the duration of diabetes (OR=1.046, P=0.013) and systolic blood pressure (OR=1.014, P=0.002) were independently associated with renal insufficiency in the elderly type 2 diabetic patients with normoalbuminuria, whereas systolic blood pressure (OR=1.042, P=0.000) and 2-hour postprandial blood glucose (OR=1.048, P=0.002) were independent risk factors for renal insufficiency of non-elderly patients. The elderly type 2 diabetic patients are likely to suffer renal insufficiency initially from a lower glomerular filtration rate than the non-elderly patients. Systolic blood pressure is the main risk factor in both elderly and non-elderly type 2 diabetes with normoalbuminuria and a decreased renal function. Controlling blood pressure may delay the decline of renal function.