“…Importantly, in heart failure patients with reduced ejection fraction on beta-blockers, VO 2 Peak retains its prognostic significance ( O’Neill et al, 2005 ), and is an important predictor of mortality in heart failure with preserved ejection fraction ( Haykowsky et al, 2011 ; Dhakal et al, 2015 ). This latter finding is particularly relevant to the renal population given that there is a disproportionate increase in heart failure with preserved ejection compared with reduced ejection fraction in CKD patients ( Loutradis et al, 2018 ). In addition to heart failure, VO 2 Peak has also been shown to be a predictor of survival in chronic lung disease ( Nixon et al, 1992 ; Gitt et al, 2002 ; Oga et al, 2003 ; Arena and Sietsema, 2011 ) and perioperative risk with major surgery ( Older et al, 1999 ; Wilson et al, 2010 ; Ting et al, 2013 ).…”