Association of blood pressure with clinical outcomes in older adults with chronic kidney disease

Abstract

Background: in chronic kidney disease (CKD), hypertension is associated with poor outcomes at ages <70 years. At older ages, this association is unclear. We tested 10-year mortality and cardiovascular outcomes by clinical systolic blood pressure (SBP) in older CKD Stages 3 and 4 patients without diabetes or proteinuria. Methods: retrospective cohort in population representative primary care electronic medical records linked to hospital data from the UK. CKD staged by CKD-EPI equation (≥2 creatinine measurements ≥90 days apart). SBPs were 3-year medians before baseline, with mean follow-up 5.7 years. Cox competing models accounted for mortality. Results: about 158,713 subjects with CKD3 and 6,611 with CKD4 met inclusion criteria. Mortality increased with increasing CKD stage in all subjects aged >60. In the 70 plus group with SBPs 140–169 mmHg, there was no increase in mortality, versus SBP 130–139. Similarly, SBPs 140–169 mmHg were not associated with increased incident heart failure, stroke or myocardial infarctions. SBPs <120 mmHg were associated with increased mortality and cardiovascular risk. At ages 60–69, there was increased mortality at SBP <120 and SBP >150 mmHg. Results were little altered after excluding those with declining SBPs during 5 years before baseline, or for longer-term outcomes (5–10 years after baseline). Conclusions: in older primary care patients, CKD3 or 4 was the dominant outcome predictor. SBP 140–169 mmHg having little additional predictive value, <120 mmHg was associated with increased mortality. Prospective studies of representative older adults with CKD are required to establish optimum BP targets.