Assessing the benefit of biological valve prostheses: cumulative incidence (actual) vs. Kaplan-Meier (actuarial) analysis

Objective: The standard method of analysing structural valve degeneration (SVD) of biological prostheses is the Kaplan-Meier method. In order to assess SVD with regard to competing risks (e.g. death particularly in elderly patients) cumulative incidence (actual analysis) was compared to Kaplan-Meier (actuarial analysis). Methods: We retrospectively analysed 257 patients older than 60 years, who underwent mitral valve replacement with different biological prostheses between 1974 and 2000. Reoperation-free survival was determined, both according to Kaplan-Meier and cumulative incidence analysis. Results: For the total group of patients older than 60 years, the 10- and 15-year freedom from reoperation was 79 +/- 5 and 55 +/- 8%, respectively, according to Kaplan-Meier and 90 +/- 2 and 83 +/- 3% according to cumulative incidence analysis. For patients older than 65 years of age (n = 170), Kaplan-Meier analysis revealed 85 +/- 7% freedom from reoperation at 10 years vs. 94 3% according to cumulative incidence analysis. For those, between 60 and 65 years of age (n = 87), Kaplan-Meier freedom from reoperation was 76 +/- 7% at 10 years and 48 +/- 9% at 15 years vs. 86 +/- 4 and 75 +/- 5% according to cumulative incidence analysis. Conclusions: Kaplan-Meier analysis overestimates the 10- and 15-year risk of SVD compared to cumulative incidence analysis, thus underestimating the benefit of biological valve replacement. Cumulative incidence analysis may lead to a more complete evaluation of risk and benefit and thus better patient management. (C) 2003 Elsevier Science B.V. All rights reserved.