Cardiovascular outcomes in the outpatient kidney transplant clinic: the Framingham risk score revisited

Abstract

Background and objectives: Cardiovascular disease is an important cause of morbidity and death in kidney transplant recipients. This study examines the Framingham risk score's ability to predict cardiac and stroke events. Because cyclosporine and tacrolimus have different cardiovascular risk profiles, these agents were also examined.

Design, setting, participants, & measurements: A prospective cohort evaluation of 540 patients were followed for a median of 4.7 yr in an outpatient kidney transplant clinic. Baseline Framingham risk scores were calculated and all cardiovascular outcomes were collected.

Results: Rates per 100 patient-years were 1.79 for cardiac and 0.78 for stroke events. The ratio of observed-to-predicted cardiac events was 1.64-fold higher [95% confidence interval (CI) 1.19 to 2.94] for the cohort, 2.74-fold higher (95% CI 1.70 to 4.24) in patients age 45 to 60 with prior cardiac disease or diabetes mellitus, but not higher in other age subgroups. Stroke was not increased above predicted. Risk scores for cardiac (c = 0.65, P = 0.003) and stroke (c = 0.71, P = 0.004) events were modest predictors. 10-yr event scores for cardiac (9.3 versus 13.5%, P < 0.001) and stroke (7.1 versus 10.0%, P = 0.002) were lower for tacrolimus compared with cyclosporine-treated patients. However observed cardiac events were higher in tacrolimus recipients (2.50, 95% CI 1.09 to 5.90) in an adjusted Cox model.

Conclusions: Although risk scores are only modest predictors, patients with the highest event rates are easily identified. Treating high-risk patients with cardioprotective medications should remain a priority.

Figures

Figure 1.

(A) Distribution of 10-yr Framingham cardiac risk scores, and (B) distribution of 10-yr Framingham stroke risk scores.

Figure 2.

(A) Event-free survival stratified by calcineurin inhibitor use for major cardiac events. (B) Event-free survival stratified by calcineurin inhibitor use for all events (cardiac, stroke, peripheral vascular disease and congestive heart failure).