342.9: Factors Associated With a Higher Need for Antihypertensive Medications at 12- Months Post Renal Transplantation

Abstract

Background: Hypertension (HTN) after renal transplantation can be difficult to control and often requires multiple blood pressure (BP) medications. In this study we examined the incidence and risk factors of “difficult to treat HTN” at one year post kidney transplantation at our center. Method: A single center retrospective study of renal transplant recipients who underwent kidney transplantation between January 2017 and May 2020 with 12 months follow up. We reviewed patients’ demographics, results of pretransplant cardiovascular imaging, and the change of cardiovascular risk factors during the first-year post kidney transplantation. We divided patients according to the number of their blood pressure medications at one year into two groups; those who required none or one, and those who required two or more medications. We labeled those who required ≥2 as “difficult to treat hypertension”. The target BP during the time of this retrospective study was <140/90 mm Hg as per the published guidelines during the time of the study.1 Results: A total of 278 renal transplant recipients were included. The majority (74%) was ≥ 30 years, 58% were men and 80% were living-donor kidney recipients. Preemptive transplantation was 10.1%. PD and HD were 11.5% and 78.4%, respectively. At one year, 70.1% of the patients attained to the target BP goal. Of the total study population; (N: 105, 38%) required ≥ 2 BP medications (i.e., “difficult to treat HTN”). Factors related to a higher need for antihypertensive medications included age (50 vs. 39 years, P<0.001), prior history of hypertension (P=0.006), prior AV fistula vs. dialysis catheter (P=0.044) and diabetes mellitus (P<0.001). Dialysis vintage (including preemptive transplantation), type of dialysis (HD vs. PD), type of transplant (living donor kidney transplant vs deceased donor kidney transplant), and smoking were not different among the two groups. Patients with “difficult to treat HTN” at one year were more likely to have abnormal pre-transplant cardiovascular baseline imaging including abnormal ejection fraction <55% (P=0.044), abnormal wall motion on echocardiography (P=0.004), abnormal perfusion stress test (P<0.001), higher calcium scoring (P=0.002), abnormal cardiac catheterization (P<0.001), and a higher degree of calcifications on CT of pelvic arteries (P=0.006). Patients with “difficult to treat HTN” at one year were likely to have a higher BMI at 12 months (P=0.028) whereas rejection, change of creatinine, weight gain, persistent hyperparathyroidism or anemia at 12 months were not different among the two groups. Multivariate analysis of requiring ≥1 BP medication indicated a relation with age (aOR: 1.025, CI: 1.003-1.048, P=0.026); male vs. female (aOR: 2.413, CI 1.358-4.288, P=0.003); DM (aOR: 2.07, CI: 1.081-3.964, P=0.028); HTN (aOR 2.586, CI: 1.104-6.06, P=0.029). However, the odds ratio for BMI at 12 months was insignificant (aOR: 0.999, CI 0.948-1.053, P=0.98). Conclusion: At one year post transplantation, about two thirds of our renal transplant recipients required no or only one BP medication. Those who required more medications were more likely to be older, males, diabetic, or previously hypertensive. Recipients with abnormal baseline pre-transplant cardiovascular imaging were also more likely to require more medications. Reference:1. Taler SJ, Agarwal R, Bakris GL, et al. KDOQI US commentary on the 2012 KDIGO clinical practice guideline for management of blood pressure in CKD. Am J Kidney Dis. 2013;62.