Background: The relationship between blood pressure (BP) and kidney function, as well as their joint influence on graft failure, is complex. This study aims to determine the independent and time-varying effect of BP on the risk of graft failure in adult kidney transplant recipients.
Methods: A total of 933 patients who underwent a deceased or living donor kidney transplant (DDKT and LDKT) at the Toronto General Hospital from 1 Jan 2000 to 31 Dec 2010 with follow-up until 31 Dec 2011 were included. Systolic BP (SBP), diastolic BP (DBP), mean arterial pressure (MAP), and pulse pressure (PP) were recorded at baseline, 1-month, 3-months, every third month until 24-months, and then yearly post-transplant. The primary outcome was the time to total graft failure (graft loss or death). The impact of BP was assessed in a marginal structural Cox model adjusting for other covariates (including kidney function as a time-dependent confounder affected by prior exposure).
Results: Over 3,928 person-years of follow-up (median 3.6 years), 128 patients achieved the primary outcome. Time-varying BP was not significantly associated with total graft failure in the total cohort or DDKT recipients (see Table). However, there was a significantly increased risk of total graft failure in LDKT recipients as a function of SBP, MAP, and PP. Moreover, donor type significantly modified the relationship between BP and outcome (P < 0.05).
Conclusions: Higher BP significantly increases the risk of total graft failure in LDKT but not DDKT recipients. The lack of measurable effect among DDKT recipients may relate to the overriding influence of other competing risk factors and/or residual confounding.
|Blood Pressure Measure||Whole Cohort||DDKT Recipients||LDKT Recipients||P for Interaction|
|SBP (per 10 mmHg)||1.07 (0.91, 1.25)||0.95 (0.77, 1.16)||1.52 (1.24, 1.87)||< 0.001|
|DBP (per 10 mmHg)||0.86 (0.67, 1.10)||0.77 (0.57, 1.03)||1.00 (0.66, 1.52)||0.29|
|MAP (per 10 mmHg)||0.96 (0.76, 1.22)||0.86 (0.61, 1.20)||1.48 (1.08, 2.04)||0.02|
|PP (per 10 mm Hg)||1.07 (0.92, 1.25)||0.97 (0.80, 1.17)||1.49 (1.19, 1.86)||0.002|
|SBP ≥ 140 or DBP ≥ 90||1.15 (0.75, 1.75)||0.87 (0.51, 1.47)||1.66 (0.88, 3.14)||0.11|
To cite this abstract in AMA style:Fozdar N, Famure O, Li Y, Kim J. Assessment of the Time-Dependent Effect of Blood Pressure on the Risk of Graft Failure in Kidney Transplant Recipients Using a Marginal Structural Model, An [abstract]. Am J Transplant. 2013; 13 (suppl 5). https://atcmeetingabstracts.com/abstract/assessment-of-the-time-dependent-effect-of-blood-pressure-on-the-risk-of-graft-failure-in-kidney-transplant-recipients-using-a-marginal-structural-model-an/. Accessed October 27, 2020.
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