Abstract
Objectives
Overweight and obesity are associated with hypertension (HTN) in renal transplant recipients (RTR). Body weight variability is known to be associated with HTN and poor cardiovascular (CV) outcomes in diabetic patients. After successful kidney transplantation (KT), weight change is very common due partly to perioperative and immunological factors. Association between body weight variability and HTN in RTR is unknown. We hypothesize that high body weight variability is associated with post-transplant HTN.
Methods
Body weight variability of RTR from a single transplant center was assessed as visit-to-visit body mass index variability (VVBMIV) by using average successive variability (ASV = the average absolute difference between successive values of BMI measured at 4, 12, 24, 36, and 48 weeks after KT). Multi-variable Cox proportional hazard regression analysis was used to examine association between post-transplant VVBMIV and systolic and diastolic HTN (SHTN and DHTN), which are defined as SBP and DBP ≥130 and 80 mmHg, respectively.
Results
Of 104 RTR, mean ± SD age was 54.29 ± 11.65 years and 62% were female. The majority (36%) were obese followed by normal weight (33%), and overweight (31%). Incidence of SBP was 0.041 person-weeks and median time to event was 12.86 weeks; while the incidence of DBP was 0.036 person-weeks with a slightly longer median time-to-event of 13 weeks. Mean ASV of BMI was 1.26 ± 0.82 kg/m2 (0.47 to 2.18). Risk of SHTN is increased 32% for every 1 kg/m2 increase in VVBMIV (HR 1.32, 95%CI 1.04 to 1.68, P 0.022). After adjusted for age, gender, and their interaction terms, very 1 kg/m2 increase in VVBMIV is associated with a 29% greater risk of developing SHTN (HR 1.29, 95% CI 1.01 to 1.65, P 0.043). However, increase in VVBMIV is not associated with an increased risk of DHTN for both univariable (HR 1.15, 95%CI 0.88 to 1.49, P 0.308) and multi-variable Cox regressions models (HR 1.13, 95%CI 0.86 to 1.49, P 0.391).
Conclusions
Post-kidney transplant VVBMIV is independently associated post-transplant SHTN, but not DHTN. Further studies is needed to examine mechanism of body weight variability and blood pressure outcomes in RTR.
Funding Sources
None.
Post-Kidney Transplant Visit-to-Visit Body Mass Index Variability as a Risk of Post-Transplant Systolic Hypertension