3. Predictive Validity
The overall scores of modified GUSS and VFSS illustrated high negative
correlation (rs=-0.931, P<0.01), and the
overall severity rating of results of modified GUSS and VFSS achieved
excellent agreement (κ=0.848, P<0.01, P0=0.900). The modified
GUSS rater found 16 patients (40.0%) with severe dysphagia, but the
VFSS rater found 19 (47.5%) patients with severe dysphagia. Predictive
values of severe dysphagia by Modified GUSS: sensitivity 84.2%,
specificity 100.0%, positive predictive value 100.0% and negative
predictive value 87.5% when compared with VFSS (κ=0.848,
P<0.01, P0=0.925). The modified GUSS rater classified 18
(45.0%) patients as having severe and moderate dysphagia, whereas the
VFSS rater classified 20 (50.0%) patients. Predictive values of severe
and moderate dysphagia by Modified GUSS: sensitivity 90.0%, specificity
100.0%, positive predictive value 100.0% and negative predictive value
90.9% when compared with VFSS (κ=0.900, P<0.01, P0=0.950).
Both raters confirmed 7 (17.5%) patients having no dysphagia in the
sample. Predictive values of dysphagia by Modified GUSS:
sensitivity、specificity、positive predictive value and negative
predictive value were all 100.0% when compared with VFSS (κ=1,
P<0.01, P0=1.00) (Table. 3 and Table. 4). The results of
modified GUSS and the days from starting oral intake to removing gastric
tube were demonstrated to have substantially negative correlation
(rs= -0.664, P<0.01).