Isolated eGFR reduction confers significant mortality risk in type 2 diabetes
medwireNews: Renal impairment, even in the absence of albuminuria, is a strong predictor of mortality in patients with type 2 diabetes, shows a large prospective study.
Mortality rates were similar for patients with isolated reduced estimated glomerular filtration rate (eGFR) and for those with isolated albuminuria, at 30.62 and 31.77 per 1000 person–years, respectively, after adjustment for age. The two forms of renal impairment increased mortality risk to a similar degree, relative to no diabetic kidney disease (DKD), after further adjustment for cardiovascular risk factors and comorbidities.
“These data highlight the need for specific interventions for individuals with type 2 diabetes presenting with this common, yet often neglected, DKD phenotype,” say the researchers.
They add that “non-albuminuric renal impairment has become the prevailing DKD phenotype” in patients with type 2 diabetes, “though it is still unclear whether it differs from the albuminuric phenotypes regarding the pathogenesis, prognosis and possibly treatment.”
Patients with both albuminuria and reduced eGFR had the highest overall mortality rate, however, at 48.65 per 1000 person–years. The rate among patients without DKD was 18.39 per 1000 person–years.
Giuseppe Pugliese (‘La Sapienza’ University, Rome, Italy) and co-researchers based their conclusions on data from 15,656 patients with type 2 diabetes participating in the Renal Insufficiency And Cardiovascular Events (RIACE) Italian multicenter study. These patients included 18.9% with albuminuria but preserved eGFR, 9.4% with isolated reduced eGFR, and 7.9% with both albuminuria and reduced eGFR. In total, 23% of the patients died during an average follow-up of 7.4 years.
Having a history of cardiovascular disease or low levels of high-density lipoprotein cholesterol was associated with mortality irrespective of the particular DKD phenotype. But beyond these the correlates of mortality differed, namely, lower levels of low-density lipoprotein cholesterol and larger waist circumference in patients with isolated reduced eGFR, but diabetic retinopathy, higher glycated hemoglobin (HbA1c), male sex, and lower diastolic blood pressure in those with preserved eGFR.
This supports “the concept that the non-albuminuric form [of DKD] is distinct from the albuminuric ones,” write the researchers in Diabetologia.
Specifically, they note that “death in the non-albuminuric phenotype was not associated with classic ‘microvascular signatures’ such as glycaemic exposure (HbA1c, diabetes duration) and diabetic retinopathy, at variance with the albuminuric phenotypes and consistent with the hypothesis of a prevailing macrovascular nature of underlying lesions.”
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