Circ Heart Fail 2011 Sep 24;4(5):578-88. Epub 2011 Jun 24.
Division of Cardiology, CardioVascular Center, Institute for Clinical Research and Health Policy Studies, Tufts Medical Center, Boston, MA, USA.
Background: Although peak oxygen consumption (peak VO(2)), 6-minute walk distance (6MW), and natriuretic peptides (BNP and NT-proBNP) are predictors of mortality in heart failure (HF) patients, it is not known whether therapy-induced changes in these measures can predict therapeutic effect on mortality. The objective of this analysis is to quantitatively assess the relationship between therapeutic effects on commonly proposed short-term markers in HF trials and therapeutic effects on long-term outcome in patients with HF and left ventricular dysfunction.
Methods And Results: We identified drug or device therapies for which there exists at least 1 randomized, controlled trial (RCT) assessing mortality over at least 6 months in at least 500 patients. For each of these therapies, we identified RCTs assessing the short-term changes in VO(2), 6MW, BNP, and NT-proBNP (few of the mortality RCTs assessed the short-term changes in markers). For each intervention, we calculated the odds ratio for mortality (using random effect meta-analysis when necessary), as well as the trial level average drug- or device-induced change in the markers. We assessed the correlation between the odds ratio for death with the placebo-corrected change in the functional parameter or biomarker across the interventions. We identified mortality RCTs of 27 distinct therapies (n=73 267 patients) with a median follow-up of 19 months, that directed the search for RCTs of the effect of those interventions on the functional markers and biomarkers. There were 54 peak VO(2) trials (n=4646 patients), 34 6MW trials (n=6995 patients), 15 BNP trials (n=7233), and 6 NT-proBNP trials (n=1946) included in this analysis. There was no significant correlation between the average therapy-induced placebo-corrected change in peak VO(2) and the odds ratio for mortality (r=0.158, P=0.26). Increased drug or device-induced average change in 6MW was correlated with increased odds ratio for mortality (r=0.373, P=0.036). There was no significant correlation between the average therapy-induced, placebo-corrected change in the natriuretic peptides and the odds ratio for mortality (BNP: r=-0.065, P=0.82, NT-proBNP: r=-0.667, P=0.15). There was no apparent relation between change in the functional parameter or biomarker and categorical effect on mortality.
Conclusions: This analysis, limited to trial level data from different therapeutic eras, suggests that drug- or device-induced effects on peak VO(2), 6MW, and natriuretic peptides found in short-term trials do not predict the corresponding average long-term therapeutic effects on mortality for patients with HF and left ventricular dysfunction.