Abstract
BACKGROUND AND OBJECTIVES: The Avosentan on Time to Doubling of Serum Creatinine, End Stage Renal Disease or Death (ASCEND) trial tested the renoprotective effect of the endothelin receptor antagonist avosentan in patients with diabetes and nephropathy, but the study was terminated due to an excess of congestive heart failure (CHF) events in the avosentan arms, likely due to fluid retention. The aim of this study was to identify risk markers of CHF after treatment with avosentan. DESIGN, SETTING, PARTICIPANTS, & MEASUREMENTS: In a post hoc analysis of the ASCEND trial (N=1392 participants), we assessed which baseline characteristics predicted CHF risk during avosentan treatment. Furthermore, postrandomization changes between baseline and the first available measurement of body weight and hemoglobin were examined as potential clinical indicators of fluid retention for their relationship with CHF development. RESULTS: Relative to placebo, avosentan increased CHF risk (hazard ratio, 2.76; 95% confidence interval, 1.68 to 4.54). The avosentan-related CHF risk was higher with lower baseline cholesterol levels (P interaction=0.003) and concomitant statin use (P interaction=0.06), whereas it was lower with a lower estimated GFR (P interaction=0.04). Patients allocated to avosentan had a median body weight increase of 0.6 kg (interquartile range, 0.0 to 2.0 kg) and a median hemoglobin decrease of 1.4 g/dl (interquartile range, -2.1 to -0.7 g/dl) at the first postrandomization measurement. The body weight increase induced by avosentan was associated with CHF development (P interaction=0.04), whereas hemoglobin decrease was not (P interaction=0.64). The increase in body weight was particularly pronounced in patients with a cardiovascular disease history and in patients using statins. CONCLUSIONS: In avosentan-treated patients, body weight increase, but not hemoglobin decrease, was associated with CHF development, indicating that close body weight monitoring could provide an early signal of CHF development in future trials with endothelin receptor antagonists.