Correction: Do Optimal Prognostic Thresholds in Continuous Physiological Variables Really Exist? Analysis of Origin of Apparent Thresholds, with Systematic Review for Peak Oxygen Consumption, Ejection Fraction and BNP

Tables 1, 4, and 5 are incorrectly shaded, and the shading does not denote negative statistical significance. The correct versions of Tables 1, 4, and 5 can be viewed below, with lines typeset in boldface indicating negative statistical significance. The images for Figures 6 and 7 are incorrectly switched. The image that appears as Figure 6 should be Figure 7, and the image that appears as Figure 7 should be Figure 6. The figure legends appear in the correct order. The correct Figure 6 and Figure 7 can be viewed below. In the Discussion section, the third paragraph under the title ‘‘Two easily-confused but different types of ‘threshold,’’’ the first sentence states ‘‘That these two types of threshold differ is sketched in Figure 5, which imagines a situation where, with only medical therapy, mortality falls smoothly with rising peak VO2, while with transplantation mortality is at a fixed level.’’ This should refer to Figure 6, which can be seen below. Also in the Discussion section, under ‘‘Prognostic studies,’’ the second sentence of the first paragraph states ‘‘For example, a flexible nonlinear function can be fitted and displayed with confidence bands for incremental log odds over the whole span of the marker; seeking a point such that risk is flat on both sides of that point but the risk on one side is much different from the risk on the other side (Figure 6).’’ This should refer to Figure 7, which can be seen below.