Factors associated with a higher need for antihypertensive medications at 12-months in postkidney transplant recipients: a retrospective cohort study

Abstract

Background: There are limited data on why some kidney transplant (KTx) recipients (KTRs) have ‘difficult-to-control (DTC) hypertension’ requiring greater than or equal to 2 antihypertensive medications while others require less antihypertensive medications post-KTx. Methods: The authors reviewed the pre-KTx cardiovascular (CV) imaging, and the changes of CV risk factors during the first-year post-KTx. The authors divided patients according to the number of their blood pressure medications at one year into two groups: requiring less than or equal to 1 and requiring greater than or equal to 2 medications (DTC hypertension). The target blood pressure during the time of this study was less than 140/90 mmHg. Results: Two hundred forty-five KTRs were included with an average age of 43.2. 56.3% were male and 79.2% were living donor KTRs. Pre-emptive KTx was 6.5%, previous coronary artery disease was 12.7%, diabetes and smoking 40.8 and 9%, respectively. 38% of the patients had DTC HTN. Risk factors were age (P<0.01), pre-KTx hypertension (P<0.01), and diabetes mellitus (P<0.01). Dialysis vintage, type of dialysis, type of KTx, and smoking were not different between the groups. Patients with abnormal pre-KTx CV imaging, including abnormal ejection fraction less than 55% (P=0.03), abnormal wall motion on echocardiography (P<0.01), abnormal perfusion stress test (P<0.01), higher calcium scoring (P<0.01), abnormal cardiac catheterization (P<0.01), or higher degree of calcifications on CT of pelvic arteries (P<0.01) were at higher risk of DTC hypertension. Post-KTx factors including rejection, change in serum creatinine and weight, A1c, new-onset diabetes post-KTx, and persistent hyperparathyroidism were not different between the groups. Multivariate analysis revealed associations with age (aOR=1.027), male sex (aOR=2.057), baseline diabetes mellitus (aOR=2.065), baseline HTN (aOR=2.82), and use of greater than or equal to 2 antihypertensive medications at 1-month post-KTx (aOR=6.146). Conclusion: At one year post transplantation, about a third of the KTRs required had DTC HTN. These patients were more likely to be older, males, diabetics, previously hypertensive, on greater than or equal to 2 HTN medications at 1-month post-KTx, and to have abnormal baseline pretransplant CV imaging.