Factors associated with adverse outcomes from cardiovascular events in the kidney transplant population: an analysis of national discharge data, hospital characteristics, and process measures.

BACKGROUND: Kidney transplant (KT) patients presenting with cardiovascular (CVD) events are being managed increasingly in non-transplant facilities. We aimed to identify drivers of mortality and costs, including transplant hospital status. METHODS: Data from the 2009-2011 Nationwide Inpatient Sample, the American Hospital Association, and Hospital Compare were used to evaluate post-KT patients hospitalized for MI, CHF, stroke, cardiac arrest, dysrhythmia, and malignant hypertension. We used generalized estimating equations to identify clinical, structural, and process factors associated with risk-adjusted mortality and high cost hospitalization (HCH). RESULTS: Data on 7803 admissions were abstracted from 275 hospitals. Transplant hospitals had lower crude mortality (3.0% vs. 3.8%, p = 0.06), and higher un-adjusted total episodic costs (Median $33,271 vs. $28,022, p < 0.0001). After risk-adjusting for clinical, structural, and process factors, mortality predictors included: age, CVD burden, CV destination hospital, diagnostic cardiac catheterization without intervention (all, p < 0.001). Female sex, race, documented co-morbidities, and hospital teaching status were protective (all, p < 0.05). Transplant and non-transplant hospitals had similar risk-adjusted mortality. HCH was associated with: age, CVD burden, CV procedures, and staffing patterns. Hospitalizations at transplant facilities had 37% lower risk-adjusted odds of HCH. Cardiovascular process measures were not associated with adverse outcomes. CONCLUSION: KT patients presenting with CVD events had similar risk-adjusted mortality at transplant and non-transplant hospitals, but high cost care was less likely in transplant hospitals. Transplant hospitals may provide better value in cardiovascular care for transplant patients. These data have significant implications for patients, transplant and non-transplant providers, and payers.

Cardiorespiratory Fitness (Peak Oxygen Uptake): Safe and Effective Measure for Cardiovascular Screening Before Kidney Transplant.

BACKGROUND: Significant heterogeneity exists in practice patterns and algorithms used for cardiac screening before kidney transplant. Cardiorespiratory fitness, as measured by peak oxygen uptake (VO2peak), is an established validated predictor of future cardiovascular morbidity and mortality in both healthy and diseased populations. The literature supports its use among asymptomatic patients in abrogating the need for further cardiac testing. METHODS AND RESULTS: We outlined a pre-renal transplant screening algorithm to incorporate VO2peak testing among a population of asymptomatic high-risk patients (with diabetes mellitus and/or >50 years of age). Only those with VO2peak <17 mL/kg per minute (equivalent to <5 metabolic equivalents) underwent further noninvasive cardiac screening tests. We conducted a retrospective study of the a priori dichotomization of the VO2peak <17 versus ≥17 mL/kg per minute to determine negative and positive predictive value of future cardiac events and all-cause mortality. We report a high (>90%) negative predictive value, indicating that VO2peak ≥17 mL/kg per minute is effective to rule out future cardiac events and all-cause mortality. However, lower VO2peak had low positive predictive value and should not be used as a reliable metric to predict future cardiac events and/or mortality. In addition, a simple mathematical calculation documented a cost savings of ≈$272 600 in the cardiac screening among our study cohort of 637 patients undergoing evaluation for kidney and/or pancreas transplant. CONCLUSIONS: We conclude that incorporating an objective measure of cardiorespiratory fitness with VO2peak is safe and allows for a cost savings in the cardiovascular screening protocol among higher-risk phenotype (with diabetes mellitus and >50 years of age) being evaluated for kidney transplant.