There was also a significant correlation with GDF-15 at follow-up (r = 0.504, p = 0.011); after correction for confounder (GFR, underlying cardiomyopathy, atrial fibrillation, and diabetes), we found an improvement in the correlation coefficient (r = 0.782, p = 0.08). This evidence concerns the gene GDF15 and atrial fibrillation.