Abstract Body: Introduction: Hypertension (HTN) is one of the most common long-term medical complications in living kidney donors (LKD). There exists a clinical need for a model to predict the severity of hypertension and adverse health effects pre-donation. Aldosterone and renin have long been implicated in the pathogenesis of HTN, but little is known about their association in LKD.

Hypothesis: We aim to examine the association between pre-donation plasma aldosterone concentration: plasma renin activity ratio (PAC/PRA) and post-donation HTN time to hypertensive event (SBP>=130 mmHg or DBP>=80 mmHg).

Methods: A single-center retrospective cohort study included LKD candidates undergoing unilateral native nephrectomy between 9/7/2021 and 8/21/2024 and having BP measurements at 6, 12, or 24 months post-donation. Multivariable Cox regression was used to examine the association between PAC/PRA and time-to-developing systolic or diastolic HTN (SHTN or DHTN) defined by SBP ≥130 or DBP ≥80 mmHg.

Results: Of 50 LKD, the mean±SD age at donation was 51±12 years, and 58% were female. The mean PAC, PRA, and PAC/PRA were 11.92±5.80 ng/dL, 1.30±1.06 ng/mL/h, and 16.50±18.26, respectively (Figure 1).
Mean BP were 118/72, 121/76, 119/74, and 123/75 mmHg at pre-donation, 6, 12, and 24 months post-donation, respectively (Figure 2)
With a median follow-up time of 9.4 months post donation, 52% developed HTN. Up to 36% experienced SHTN, while 42% had DHTN.
Median time to developing post-donation SHTN and DHTN were 11.62 and 11.32 months, respectively.
After adjusting for age, gender, race/ethnicity, BMI, BUN, dietary sodium intake, dietary potassium intake, dietary protein intake, eGFR, thyroid-stimulating hormone, triiodothyronine, total cholesterol, triglyceride, HDL, and LDL, every 1 unit increase in PAC/PRA was associated with 85% decrease in post-donation SHTN (aHR 1.149, 95%CI 1.100, 1.200; P <0.00001; Figure 3). There was no significant PAC/PRA – DHTN association.

Conclusions: Pre-donation PAC/PRA is positively associated with post-donation SHTN, but not DHTN. Further longitudinal studies are required to elucidate the potential mechanism for the association.