Abstract Body (Do not enter title and authors here): Background: Living kidney donors (LKD) are at risk for developing hypertension (HTN); however, the levels of pre-donation blood pressure (BP) that may predict post-donation BP are unknown.

Hypothesis: Higher pre-donation BP is associated with a greater risk of developing post-donation HTN.

Goals: We aim to examine the association between pre-donation BP and the risk of developing HTN in LKD.

Methods: A retrospective cohort study using OPTN/SRTR included adult LKD undergoing donation between 6/1972 and 9/2022. Systolic and diastolic hypertension (SHTN and DHTN) were defined by SBP ≥130 and DBP ≥80 mmHg, respectively. Multiple Cox regression was utilized to examine the association between decile of pre-donation BP and time-to-event of developing post-donation SHTN and DHTN.

Results: Of 174,311 adult LKD, the mean±SD age was 41±12 years and 60% were female. Mean pre- and post-donation SBP and DBP and deciles of BP are shown in Table 1 and Figure 1, respectively. The median time to follow-up for developing SHTN was 13.2 (IQR 6.8, 24.4) and DHTN was 12.2 months (IQR 6.3, 24.1). The incidence rate of developing SHTN and DHTN was 0.020 and 0.03 person-months, respectively. After adjusting for age (<65 vs. ≥65 y/o), gender, race, U.S. citizenship, education level, history of pre-donation HTN, diabetes, pre-donation BMI, DBP, eGFR, urine protein:creatinine ratio, and the interaction term between decile of pre-donation SBP and age, LKD in deciles 5 to 10 (SBP 119–200 mmHg) had significantly graded increased risk for developing SHTN compared to LKD in decile 4 (SBP 115-118 mmHg; HR_decile10 4.82, 95%CI 3.37, 6.91), while those in deciles 1 to 3 had a graded decrease in the risk but were non-significant (HR_decile1 0.68, 95CI% 0.42, 1.11). In addition, there was a decreased risk of SHTN observed in elderly LKD (≥65 y/o) in deciles 5 and 10 (P_interaction 0.041 and 0.009). The pattern of pre-donation DBP decile – DHTN association was similar to the SBP – SHTN association, but only DBP deciles 8-10 (DBP 81–195 mmHg) were significant (HR_decile10 2.10, 95%CI 1.31, 3.34); Figur 2. There was no interaction between pre-donation DBP and age.

Conclusions: Elevated pre-donation SBP or DBP greater than 118 or 80 mmHg is associated with a graded increase in developing post-donation SHTN or DHTN, respectively especially in the non-elderly (<65 years old) LKD. BP control during the pre-donation period should be achieved to mitigate the risk of post-donation HTN.