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. 2021 Dec 13;11:23904. doi: 10.1038/s41598-021-03456-9

Table 4.

Receiver operating characteristic (ROC) analysis of salivary redox biomarkers of patients with Alzheimer’s disease and the control group.

Biomarker Saliva
AUC 95%Cl P-value Cut off Sensitivity% 95%Cl Specificity% 95%Cl
Antioxidant barrier
SOD (mU/mg protein) 0.7774 0.6292 to 0.9256 0.001  < 1.028 69.57 49.13 to 84.40% 68.00 48.41 to 82.79%
CAT (nmol H2O2/min/mg protein) 0.9183 0.8267 to 1.000  < 0.0001  < 0.4197 82.61 62.86 to 93.02% 84.00 65.35 to 93.60%
GPx (mU/mg protein) 0.7409 0.5841 to 0.8976 0.0043  < 0.07697 73.91 53.53 to 87.45% 72.00 52.42 to 85.72%
UA (μg/mg protein) 0.5739 0.3950 to 0.7528 0.3804  < 66.40 52.17 32.96 to 70.76% 52.00 33.50 to 69.97%
GSH (ng/mg protein) 0.6836 0.5258 to 0.8415 0.0313  < 2.276 72.73 51.85 to 86.85% 72.00 52.42 to 85.72%
Redox status
TAC (μmol/mg protein) 0.5183 0.3442 to 0.6923 0.8284  > 5.999 52.17 32.96 to 70.76% 52.00 33.50 to 69.97%
TOS (nmol/mg protein) 0.92 0.8137 to 1.000  < 0.0001  > 367.6 91.30 73.20 to 98.45% 92.00 75.03 to 98.58%
OSI (TOS/TAC ratio) 0.936 0.8473 to 1.000  < 0.0001  > 59.10 90.00 69.90 to 98.22% 92.00 75.03 to 98.58%
Oxidative and nitrosative stress
AGE (AFU/mg protein) 0.9357 0.8505 to 1.000  < 0.0001  > 0.9610 86.96 67.87 to 95.46% 88.00 70.04 to 95.83%
AOPP (nmol/mg protein) 0.68 0.5307 to 0.8293 0.029  > 20.19 56.00 37.07 to 73.33% 56.00 37.07 to 73.33%
MDA(μg/mg protein) 0.6876 0.5075 to 0.8677 0.0298  > 243.7 66.67 45.37 to 82.81% 68.00 48.41 to 82.79%
NO (ng/mg protein) 0.672 0.5229 to 0.8211 0.037  > 0.1961 56.00 37.07 to 73.33% 56.00 37.07 to 73.33%
Peroxynitrite (nmol/mg protein) 0.8163 0.6927 to 0.9398 0.0002  > 16.74 63.64 42.95 to 80.27% 79.17 59.53 to 90.76%
Nitrotyrosine (pmol/mg protein) 0.7018 0.5405 to 0.8631 0.018  > 2107 63.64 42.95 to 80.27% 64.00 44.52 to 79.75%
Others
Aβ (AFU/mg protein) 0.9491 0.8941 to 1.000  < 0.0001  > 5861 86.36 66.67 to 95.25% 84.00 65.35 to 93.60%
LF (μg/mg protein) 0.6896 0.5368 to 0.8424 0.0215  < 26.36 64.00 44.52 to 79.75% 64.00 44.52 to 79.75%
IL-1β (ng/mg protein) 0.8528 0.7420 to 0.9636  < 0.0001  > 76.95 84.00 65.35 to 93.60% 84.00 65.35 to 93.60%

AUC—area under curve; SOD—superoxide dismutase; CAT—catalase; GPx—glutathione peroxidase; UA—uric acid; GSH—glutathione; TAC—mean total antioxidant capacity; TOS—mean total oxidant status; OSI—oxidative stress index; AGE—advanced glycation end products; AOPP—advanced oxidation protein products; MDA—malondialdehyde; NO—nitric oxide, Aβ—amyloid beta, LF—lactoferrin; IL-1β—Interleukin 1 Beta.