Chronic kidney disease influences mortality in type 2 diabetes

Although urine albumin-to-creatinine ratios are improving among patients with diabetes, mortality remains an issue in patients with low estimated glomerular filtration rates and albumin-to-creatinine ratios less than 30 mg/g, according to findings published in Diabetes Care.

“Diabetes increases the risk for cardiovascular disease and mortality and now accounts for almost 12% of deaths in the U.S. adult population, making diabetes the third leading cause of death after heart disease and cancer,” Holly Kramer, MD, MPH, of the department of public health sciences at Loyola University Chicago, and colleagues wrote. “However, previous studies have shown that the excess mortality risk associated with diabetes is mainly noted in those with chronic kidney disease, defined as an estimated glomerular filtration rate (eGFR) less than 60 mL/min/1.73 m² and/or increased urine albumin excretion. … Concurrent with temporal changes in diabetes management, the frequency of increased urine albumin excretion has declined while low eGFR in the U.S. population with diabetes has increased and low eGFR in the absence of increased urine albumin excretion has become more prevalent.”

Kramer and colleagues examined mortality trends in adults with diabetes using data from the National Health and Nutrition Examination Surveys from 1988 to 2006. The researchers also analyzed mortality trends by chronic kidney disease phenotype using the National Death Index through Dec. 31, 2011.

The number of adults with eGFR less than 60 mL/min/1.73m² and urine albumin-to-creatinine ratio less than 30 mg/g rose from about 0.9 million (6.6% of total diabetes population; 95% CI, 0.7-1.1) in the period between 1988 and 1994 to 2.4 million in the period between 2007 and 2010 (10.1% of diabetes population; 95% CI, 1.9-2.9), Kramer and colleagues reported.

In general, mortality trended downward for patients who had diabetes and albumin-to-creatinine ratio 30 mg/g or more, the researchers wrote.

However, mortality rose in patients with eGFR less than 60 mL/min/1.73m² and albumin-to-creatinine ratio less than 30 mg/g. Mortality rates in this group rose from 35 deaths per 1,000 person-years (95% CI, 22-55) in the period between 1988 and 1994 to 51 deaths per 1,000 person-years (95% CI, 33-83) between 2003 and 2006.

The researchers wrote that these findings indicated that the clinical presentation of chronic kidney disease had changed in recent years.

“Apart from targeting [chronic kidney disease] progression in those with severely increased urinary albumin excretion, clinical interventions and public health policies should also address the high mortality rates in adults with diabetes and low eGFR in the absence of increased urine albumin excretion,” Kramer and colleagues wrote. – by Andy Polhamus

Disclosures: The authors report no relevant financial disclosures.