Abstract 293: Predictors Of Repeat Cardiovascular Testing In Patients Who Receive An Index Negative Stress Echocardiography

Abstract

Background: Repeat cardiovascular imaging in most situations is of indeterminate appropriateness. We sought to identify baseline characteristics associated with repeat testing in patients who had an initial negative test result. Methods: Medicare beneficiaries who had a negative index stress echo (SE) between 2002-2008 were linked to corresponding Medicare claim data. We identified the nature and date of claims for repeat cardiac testing (exercise stress test, SE, cardiac PET, cardiac SPECT, or angiography). Kaplan-Meier analysis and Cox proportional hazards (CPH) analysis were used to determine the association of baseline covariates on the risk of a repeat test. The pre-defined outcome endpoint included time to first repeat test. Results: Of 3,113 Medicare beneficiaries with a negative SE (mean follow-up, 2.6 ± 1.9 years), 1553 (50%) received subsequent imaging [1411 (91%) white, 85 (5.5%) African-American, 55 (3.5%) Hispanic, Asian, or other origin]. Kaplan-Meier analysis stratified by race was associated with repeat cardiovascular imaging (p <0.0001). CPH analysis revealed that race, hyperlipidemia, CAD, T-wave changes after stress, resting diastolic blood pressure, maximum rate pressure product, percent peak maximum heart rate, and patients using aspirin and beta blockers were independently associated with repeat testing (χ 2 =242.3, P<0.0001). After risk-adjustment, African-American patients were half as likely to have a repeat test compared to white patients (HR 0.52 [0.40-0.70], p<.001) independent of other variables. Conclusions: Although some repeat testing in patients with negative studies reflects risk level, the presence of racial differences suggests that nonmedical factors may have an important role.