Proteinuria modifies the effect of systolic blood pressure on total and cardiovascular disease mortality in patients with type 2 diabetes
Correspondence: Teemu Vepsäläinen, Department of Medicine, University of Turku, Kiinamyllynkatu 10, 20520 Turku, Finland.
(fax: (+3582) 313 2030; e-mail firstname.lastname@example.org).
Hypertension and proteinuria are major risk factors for cardiovascular disease (CVD) mortality in patients with type 2 diabetes. Blood pressure (BP) targets have been progressively lowered in these patients to prevent or delay the progression of nephropathy. However, no long-term population-based studies have been reported on the interaction between BP and proteinuria with respect to total and CVD mortality in patients with type 2 diabetes.
We prospectively followed 881 middle-aged type 2 diabetic patients, free of CVD events at baseline, for up to 18 years. Participants were categorized into four groups according to baseline systolic BP (<130, 130–139, 140–159 and ≥160 mmHg) and further stratified by proteinuria (≤150 or >150 mg L−1). Cox proportional hazards model was used to estimate the joint association between systolic BP and proteinuria and the risk of mortality.
During follow-up, 607 patients died including 395 because of CVD. After adjustment for confounding factors, total and CVD mortality were significantly higher in patients with proteinuria and systolic BP <130 mmHg compared with those with systolic BP between 130 and 160 mmHg. The prognosis was similar in patients with systolic BP <130 mmHg or ≥160 mmHg. Among patients without proteinuria, systolic BP <130 mmHg was associated with a nonsignificant reduction in mortality.
Type 2 diabetic patients with proteinuria and with systolic BP <130 mmHg may have an increased risk of CVD mortality. The presence of proteinuria should be taken into account when defining the target systolic BP level for the prevention of fatal CVD events in patients with type 2 diabetes.