GDF15 and atrial fibrillation: Future research should includeYouden index to determine optimal cutoff values, balancing sensitivity andspecificity, to enhance the clinical utility of GDF-15 in risk stratification.Fourth, this study analyzed GDF-15 as a predictor of all-cause mortality,cardiovascular death, atrial fibrillation, AKI, and spontaneous MI as adverseoutcomes [16].