Microvascular disease: what does the UKPDS tell us about diabetic nephropathy?

The UK Prospective Diabetes Study is the largest study in Type 2 diabetes with pre-specified renal outcomes. The study showed that the natural history of nephropathy in newly diagnosed Type 2 diabetic patients was similar to that described previously in those with Type 1 diabetes. Around 2% per annum progress from normo- to micro-albuminuria [urinary albumin concentration (UAC) > 50 mg/l] and a further 2% from microalbuminuria to clinical grade proteinuria (UAC > 300 mg/l). Mortality rates for those with nephropathy are high, increasing from 1.4% per annum (normoalbuminuria) to 4.6% per annum (clinical grade proteinuria), and to 19.2% per annum for those with renal impairment. More intensive blood glucose control resulted in both a 33% reduction in relative risk of development of microalbuminuria or clinical grade proteinuria at 12 years, and a significant reduction in the proportion doubling their plasma creatinine (0.91 vs. 3.52%, P = 0.0028). Tighter blood pressure control also reduced microalbuminuria and clinical grade proteinuria; but at 6 years there was no effect on plasma creatinine levels. These data underline the importance of glycaemic and blood pressure control in Type 2 diabetes in order to prevent diabetic nephropathy. Those patients unlucky enough to develop nephropathy need intensive surveillance and correction of cardiovascular risk factors.