GDF15 and Cachexia: Although the study utilized spot urine samples rather than a 24 h urine sample, our recent study using spot urine analysis showed that urinary creatinine concentrations were associated with smaller body dimensions (lower BMI, height, and weight) and an increased risk of (>5%) weight loss at 9 months.37 The inverse correlation of muscle mass and protein intake with GDF15 and raised GDF15 levels in patients with cachexia, support the concept that GDF15 plays a role in driving cardiac cachexia.