Blood pressure, aortic stiffness predict renal outcomes in type 2 diabetes patients
medwireNews: High ambulatory systolic blood pressure (BP) and increased aortic stiffness are associated with the development and progression of kidney disease among patients with type 2 diabetes, study results suggest.
The Rio de Janeiro Type 2 Diabetes Cohort Study investigators evaluated predictors of renal outcomes among 629 adult attendees of a diabetes outpatient clinic, who either had microvascular or macrovascular complications, or two or more other modifiable cardiovascular risk factors. A total of 197 participants had diabetic kidney disease (DKD) at baseline.
Over a median 7.8 years of follow-up, 31.0% of participants experienced the composite renal endpoint of development or progression of DKD – defined as a change from a normal albumin excretion rate (<30 mg/24 h) to microalbuminuria (30–299 mg/24 h) or from microalbuminuria to macroalbuminuria (≥300 mg/24 h) – or worsening of renal function, indicated by a doubling of serum creatinine to at least 200 µmol/L.
The 195 patients who experienced the composite outcome had significantly higher mean first-year glycated hemoglobin (HbA1c) levels (7.9 vs 7.6%), daytime ambulatory systolic blood pressure (134 vs 129 mmHg), and aortic stiffness as indicated by carotid–femoral pulse wave velocity (9.1 vs 8.6 m/s) than the 434 patients who remained stable with respect to renal outcomes.
In a Cox analysis adjusting for factors including age, sex, diabetes duration, and drug treatment, average first-year HbA1c levels and ambulatory daytime systolic BP significantly predicted the likelihood of experiencing the composite renal endpoint (hazard ratio [HR]=1.22 and 1.29, respectively), while aortic stiffness was a significant predictor of albuminuria development or progression (HR=1.26).
The researchers note that these findings were largely consistent in competing risks analyses, but the ability of HbA1c to predict the primary renal endpoint was “attenuated” and no longer statistically significant.
When different methods of measuring BP were compared, baseline ambulatory BP was a stronger predictor of DKD development and progression than clinic systolic BP, and “[t]his was particularly evident for clinical renal failure outcomes,” report Gil Salles and fellow researchers, from Universidade Federal do Rio de Janeiro in Brazil.
“Overall, our findings not only emphasise the pivotal role of optimising control of blood glucose and BP in the prevention of DKD development/progression, but also provided strong support for more widespread use of ambulatory BP monitoring and aortic stiffness assessment in clinical diabetes management,” they write.
The study authors caution, however, that their observational study was not able to demonstrate causality, and that their results may not be applicable to patients with recent-onset diabetes or those treated in primary care.
And they conclude in Diabetologia: “Whether specifically targeting ambulatory BP and attenuating aortic stiffness, beyond the recommended clinic BP and blood glucose control, will be able to prevent or delay development or progression of DKD shall be the focus of future intervention studies.”
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