Background: In the growing elderly predialysis population, little is known about the effect of identified risk factors on the progression to end-stage renal disease. Therefore, we investigated the association of systolic (SBP) and diastolic blood pressure (DBP) with the start of renal replacement therapy (RRT), in elderly (≥65 years) compared with young (<65 years) predialysis patients.
Methods: In the PREPARE-1 cohort, 547 incident predialysis patients, referred as part of the usual care to eight Dutch predialysis care outpatient clinics, were included (1999-2001) and followed until the start of dialysis, transplantation, death, or until 1 January 2008. The outcome was the start of RRT. All analyses were stratified for age; <65 years (young) and ≥65 years (elderly).
Results: In young predialysis patients (n = 268) higher SBP (every 20 mm Hg increase) and high DBP (DBP ≥100 mm Hg compared with 80-89 mm Hg) were associated with a higher rate of starting RRT (adjusted hazard ratio (HR) (95% confidence interval) 1.21 (1.09;1.34) and 1.74 (1.16;2.62), respectively). However, in elderly predialysis patients (n = 240) only patients with SBP ≥180 mm Hg had an increased rate compared with patients with 140-159 mm Hg (adjusted HR 2.33 (1.41;3.87)). Furthermore, patients with DBP <70 or ≥100 mm Hg had an increased rate of starting RRT, independent of SBP, compared with patients with 80-89 mm Hg (fully adjusted HR 1.72 (1.01;2.94) and 2.05 (1.13;3.73), respectively).
Conclusions: The association of SBP and DBP with the start of RRT is different between elderly and young predialysis patients.