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

Objective: To investigate the clinical features and risk factors of renal damage in the elderly and non-elderly patients with type 2 diabetes mellitus.

Methods: 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 (30or=300 mg/24 h). eGFR was estimated by the equation from the MDRD study. Clinical and laboratory parameters of all patients were analyzed.

Results: (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.

Conclusion: 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.