Relationship between low blood pressure and renal/cardiovascular outcomes in Japanese patients with chronic kidney disease under nephrologist care: the Gonryo study

Background: Previous studies established a J-shaped association between blood pressure (BP) and cardiovascular disease (CVD) in chronic kidney disease (CKD), and the different clinical profiles of CVD by ethnicity. However, the adequately lower BP target remains unclear in Asian patients with CKD. Methods: This prospective observational study included 2,655 Japanese outpatients with CKD under nephrologist care who met the inclusion criteria, namely estimated glomerular filtration rate <60 mL/min and/or presenting proteinuria. The patients were divided by 10-mmHg BP increments by clinical data. The end points were death, cardiovascular events (CVEs), and end-stage kidney disease (ESKD) that requires renal replacement therapy. Results: During a 3.02-year median follow-up, 64 patients died, 120 developed CVEs, and 225 progressed to ESKD. In the adjusted Cox models, the risks of CVEs and all-cause mortality were higher in the patients with systolic BPs (SBPs) < 110 mmHg than in those with SBPs of 130–139 mmHg. Moreover, the risk was higher in those with diastolic BPs (DBPs) < 70 mmHg than in those with DBPs of 80–89 mmHg. Although SBPs ≥ 140 mmHg were associated with higher incidence rates of ESKD, no significant increased risk was associated with BPs < 130/80 mmHg. Conclusions: SBPs < 110 mmHg and DBPs < 70 mmHg were independent risk factors of CVEs and all-cause mortality. No lower BPs were observed as significant risk factors of progression to ESKD. This study suggests that the lower BP target in Asian patients with CKD should be ≥110/70 mmHg.