Patients with type 2 diabetes and kidney disease are at high risk of death over the next ten years, according to a study from the US.

The researchers examined 10-year cumulative mortality by diabetes and kidney disease status for 15,046 participants in the third National Health and Nutrition Examination Survey (NHANES III). Baseline data were linked to the National Death Index. Mortality data were standardised to population age, sex, and race. Kidney disease was defined as urinary albumin:creatinine ratio ≥30 mg/g and/or eGFR ≤60 ml/min per 1.73 m².

Nearly half, 42.3%, of patients with type 2 diabetes had kidney disease compared with 9.4% of those without diabetes.

In the reference group of patients with neither diabetes nor kidney disease the 10-year cumulative all-cause mortality was 7.7% (95% CI:7.0-8.3%). In diabetes patients without kidney disease the respective mortality figure was 11.5% (95% CI:7.9-15.2%).This represents an absolute risk difference of 3.4% (95% CI: −0.3 to 7.0%) with additional adjustment for smoking, blood pressure, and cholesterol.

For patients with diabetes and kidney disease mortality soared to 31.1% (95% CI:24.7-37.5%). This gave an absolute risk difference over the reference group of 23.4% (95% CI: 17.2–29.6%) when adjusted for smoking, blood pressure and cholesterol.

The authors conclude that those patients with kidney disease predominantly account for the increased mortality observed in type 2 diabetes and that the presence of kidney disease appears to identify a diabetes subpopulation at high risk of death.

They also point out that accelerating the rate of cardiovascular disease appears to be one of the major ways that kidney disease contributes to increased mortality in patients with diabetes.

The take home point for primary care is that we need to focus on preventing kidney disease in diabetes patients and slowing progression when it is present. Control of blood pressure, early detection and treatment of microalbuminuria and good glycaemic control will all be key in this process.

Dr Peter Savill

• Afkarian M, Sachs MC, Kestenbaum B et al. Kidney disease and increased mortality risk in type 2 diabetes. J Am Soc Nephrol 2013; DOI:10.1681/ASN.2012070718