In a model adjusted for clinical variables, baseline GDF-15 (SHR, 1.32; 95% CI, 1.02–1.69), MMP-8 (SHR, 1.14; 95% CI, 1.01–1.30) and CRP (SHR, 1.16; 95% CI, 1.06–1.27) remained significant predictors of pneumonia (Figure 2c). Here, GDF15 is linked to susceptibility to pneumonia measurement.