Association Between Systolic Blood Pressure Time in Target Range and Graft Outcomes in Kidney Transplant Recipients: Result From KOTRY and KNOW-KT

초록

Background Time in target range (TTR) for blood pressure reflects the consistency of blood pressure control and may better predict outcomes than single measurements. We examined the association between systolic blood pressure (SBP)-TTR and graft outcomes in kidney transplant recipients. Methods We conducted a prospective observational cohort study including 4559 kidney transplant recipients from the nationwide KOTRY (Korean Organ Transplantation Registry; main cohort) and 828 from the multicenter KNOW-KT (Korean Cohort Study for Outcome in Patients With Kidney Transplantation; replication cohort). SBP-TTR within 110 to 130 mm Hg was calculated using linear interpolation of office blood pressure at 6, 12, and 24 months after transplantation (12, 24, and 36 months in the replication cohort). The primary outcome was a composite of death-censored graft loss or >= 50% decline in estimated glomerular filtration rate. Results Over a median follow-up of 4 years, each 1-SD increase in SBP-TTR was associated with a 20% lower risk of the composite outcome (adjusted hazard ratio [aHR], 0.80 [95% CI, 0.71-0.91]). Compared with the 0% SBP-TTR group, the 1% to 50%, 51% to 99%, and 100% SBP-TTR groups had progressively lower risks (aHRs, 0.69 [95% CI, 0.50-0.95]; 0.63 [95% CI, 0.46-0.87]; and 0.47 [95% CI, 0.31-0.71], respectively). Stronger associations were observed among recipients of deceased donor kidneys and those with older or female donors or a higher baseline SBP. The replication cohort showed similar associations. All-cause death was not significantly associated with SBP-TTR after multivariable adjustment in either the main cohort (aHR per 1-SD increase, 0.88 [95% CI, 0.71-1.09]) or the replication cohort. Conclusions A higher proportion of time with SBP within the target range of 110 to 130 mm Hg was associated with a lower risk of graft dysfunction, with consistent effects across most subgroups and more pronounced benefits in high-risk populations. These findings suggest that sustained SBP control within this range may be clinically relevant in kidney transplant recipients; however, randomized controlled trials are needed to confirm causality and inform therapeutic strategies.

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