Table 5.
AUCs of Cardiovascular Mortality Prediction Before and After Adding DFAα1 and MSE Area 1 to 5 to Linear and Nonlinear Variables in NRI and IDI Models
| Variables | AUC (95% CI) | P Value, DeLong test | cNRI (95% CI) | P Value, cNRI | IDI (95% CI) | P Value, IDI |
|---|---|---|---|---|---|---|
| Area 1–5 | 0.674 (0.564–0.783) | ··· | ··· | ··· | ··· | ··· |
| Plus DFAα1 | 0.787 (0.709–0.864) | 0.0144 | 0.75 (0.326–1.174) | 0.0016 | 0.103 (0.043–0.163) | 0.0008 |
| SDRR | 0.519 (0.408–0.631) | ··· | ··· | ··· | ··· | ··· |
| Plus DFAα1 | 0.757 (0.672–0.841) | 0.003 | 0.821 (0.399–1.244) | <0.001 | 0.097 (0.041–0.154) | 0.0007 |
| Plus Area 1–5 | 0.792 (0.715–0.869) | 0.0004 | 0.952 (0.551–1.353) | <0.001 | 0.176 (0.075–0.277) | 0.0006 |
| VLF | 0.632 (0.505–0.760) | ··· | ··· | ··· | ··· | ··· |
| Plus DFAα1 | 0.758 (0.675–0.840) | 0.0029 | 0.416 (−0.037 to 0.870) | 0.0797 | 0.057 (0.017–0.097) | 0.0056 |
| Plus Area 1–5 | 0.787 (0.709–0.864) | 0.0008 | 0.75 (0.326–1.174) | 0.0007 | 0.124 (0.042–0.206) | 0.0029 |
| LF | 0.662 (0.533–0.791) | ··· | ··· | ··· | ··· | ··· |
| Plus DFAα1 | 0.755 (0.672–0.839) | 0.0099 | 0.553 (0.125–0.981) | 0.0199 | 0.058 (0.017–0.100) | 0.0057 |
| Plus Area 1–5 | 0.788 (0.712–0.865) | 0.0053 | 0.720 (0.313–1.127) | 0.0025 | 0.118 (0.032–0.203) | 0.0068 |
| HF | 0.544 (0.399–0.689) | ··· | ··· | ··· | ··· | ··· |
| Plus DFAα1 | 0.764 (0.684–0.845) | 0.0002 | 0.785 (0.362–1.209) | 0.001 | 0.101 (0.045–0.158) | 0.0004 |
| Plus Area 1–5 | 0.790 (0.713–0.868) | 0.0001 | 0.839 (0.417–1.26) | 0.0004 | 0.175 (0.071–0.280) | 0.001 |
| LF/HF ratio | 0.725 (0.613–0.838) | ··· | ··· | ··· | ··· | ··· |
| Plus DFAα1 | 0.739 (0.635–0.843) | 0.2597 | −0.012 (−0.477 to 0.453) | 0.9601 | 0.003 (−0.014 to 0.021) | 0.7149 |
| Plus Area 1–5 | 0.775 (0.682–0.867) | 0.0824 | 0.232 (−0.229 to 0.693) | 0.329 | 0.074 (0.005–0.142) | 0.0345 |
AUC indicates area under the curve; cNRI, category‐free (continuous) net reclassification improvement; DFA, detrended fluctuation analysis; DFAα1, short‐term DFA; HF, high frequency; IDI, integrated discrimination improvement; LF, low frequency; MSE, multiscale entropy; NRI, net reclassification improvement; SDRR, standard deviation of normal R‐R intervals; VLF, very low frequency.