GDF15 and diabetes mellitus: Major determinants of GDF-15 were age, diabetes, NT-proBNP, renal function and hypertension, which are in keeping with the findings of previous studies.9–12 Additionally, myocardial fibrosis, measured using CMR ECV, was an independent determinant of GDF-15, which is in keeping with the study by Lok et al,31 who, in a small group of patients with advanced non-ischaemic cardiomyopathy, found GDF-15 to be moderately correlated with histological collagen volume (r=0.61, p=0.01).