Impact of Cardiovascular Risk Factors on Graft Outcome Disparities in Black Kidney Transplant Recipients

Abstract

Although outcome inequalities for non-Hispanic Black (NHB) kidney transplant recipients are well documented, there is paucity in data assessing the impact of cardiovascular disease (CVD) risk factors on this disparity in kidney transplantation. This was a longitudinal study of a national cohort of veteran kidney recipients transplanted between Jan 2001 and Dec 2007. Data included baseline characteristics acquired through the USRDS linked to detailed clinical follow up information acquired through the VA electronic health records. Analyses were conducted using sequential multivariable modeling (Cox regression), incorporating blocks of variables into iterative nested models; 3,139 patients were included (2,095 NHW [66.7%] and 1,044 NHBs [33.3%]). NHBs had a higher prevalence of hypertension (100% vs. 99%, p<0.01) and post-transplant diabetes (59% vs. 53%, p<0.01) with reduced control of hypertension (BP <140/90, 60% vs. 69% p<0.01), diabetes (A1c <7%, 35% vs. 47%, p<0.01) and LDL (<100 mg/dL, 55% vs. 61%, p<0.01). Adherence to medications used to manage CVD risk was significantly lower in NHBs. In the fully adjusted models, the independent risk of graft loss in NHBs was substantially reduced (unadjusted HR 2.00 vs. adjusted HR 1.49). CVD risk factors and control reduced the influence of NHB race by 9–18%. Similar trends were noted for mortality and estimates were robust across in sensitivity analyses. These results demonstrate that NHB kidney transplant recipients have significantly higher rates of CVD risk factors and reduced CVD risk control. These issues are likely partly related to medication non-adherence and meaningfully contribute to racial disparities for graft outcomes.

Pharmacist‐led, technology‐assisted study to improve medication safety, cardiovascular risk factor control, and racial disparities in kidney transplant recipients

“…In a more recent analysis using national data, our research group demonstrated that posttransplant BP control (<140/90 mmHg) was significantly less common in AAs as compared with non‐AAs (60% vs 69%, P < 0.01). In multivariable modeling, adjusting for BP control significantly reduced the influence of race on graft loss . Thus, it is likely that improved BP control is necessary to improve graft outcome disparities for AAs.…”

“…The study was powered based on improving posttransplant hypertension control to goal levels. Grounded on preliminary data, we expected ~30% of kidney recipients to meet optimal hypertension goals (<130/80) . Using this as the baseline rate of control, this study had 80% power to detect an 18% improvement in rate of optimal BP control (30% baseline, 48% at the end of follow‐up).…”

“…Over the past 5 years, our research collaborative has set out to better understand the impact cardiovascular disease (CVD) risk factors and risk control has on racial disparities. Using both single‐center and national cohort studies, we have previously demonstrated that CVD risk factors (diabetes, hypertension, and dyslipidemia) are more prevalent in posttransplant AA recipients . Furthermore, AA recipients have significantly reduced control of diabetes and hypertension after transplant, when compared with non‐AA recipients.…”

“…Furthermore, AA recipients have significantly reduced control of diabetes and hypertension after transplant, when compared with non‐AA recipients. Through iterative multivariate modeling, we have demonstrated that control of CVD risk factors explains a significant portion of the increased risk of graft loss within AA kidney transplant recipients …”

Concepts of Genomics in Kidney Transplantation

“…African Americans who do not carry these variants are assumed to carry the CYP3A5*1 allele and express high amounts of active CYP3A5 enzyme which confers a rapid metabolism phenotype, resulting in rapid tacrolimus clearance. African Americans, who more frequently carry a CYP3A5*1 allele and have higher risk of poorer outcomes, 30,31 may benefit most from genotype-directed dosing.…”