Diabetes is a major risk factor for the development of kidney disease and is the leading cause of end-stage renal disease in the U.S. However, whether pre-diabetes is associated with the development of kidney disease is unclear.
The finding, that declines in kidney function are present early on among subjects with glucose intolerance could help direct therapeutic interventions to prevent the progression of kidney disease. Recently, researchers, writing in the October issue of Diabetes Care sought to examine the development of chronic kidney disease (CKD) in adults with pre-diabetes, metabolic syndrome, and diabetes in the general population, using the Framingham Heart Study to conduct this longitudinal study.
Subjects free of CKD were given an oral glucose tolerance test, and followed for an average of 7 years for development of CKD. Multivariable logistic regression models, adjusted for cardiovascular disease risk factors including age, sex, hypertension, smoking, BMI, total and HDL cholesterol levels, and prevalent myocardial infarction or congestive heart failure, were used to estimate the odds of patients developing kidney disease among glycemic categories.
Of 2,398 subjects, 63% were normoglycemic, 29% had impaired fasting glucose (IFG) or impaired glucose tolerance (IGT), 3.4% were newly diabetic, and 4.6% had known diabetes.
The risk of developing chronic kidney disease associated with pre-diabetes and newly diagnosed diabetes is largely accounted for by coexisting vascular disease risk factors. Similarly, vascular disease risk factors attenuated most of the relationship between insulin resistance and CKD. Gradation of risk for CKD appears to be linear across the spectrum of glycemic status, and known diabetes is a strong and independent risk factor for CKD.
Findings from this study suggest that concomitant vascular disease risk factors explain most of the increased odds of development of CKD seen among participants with IFG and newly diagnosed diabetes. Traditionally, diabetic nephropathy is thought to be a microvascular complication of diabetes, characterized by the classic Kimmelstiel-Wilson syndrome lesion. Data from this study suggest that CKD in the setting of pre-diabetes might be thought of as an additional complication of macrovascular atherosclerosis.
However, the researchers assert that clinical trials are warranted to determine whether vascular risk factor modification can slow the decline of kidney function among those with pre-diabetes.