TABLE 5.
Significance testing of mixed‐effects model predictors with nocturnal heart rate (HR), standard deviation of the R–R interval (SDNN) and high frequency heart rate variability based on frequency bands from spectral analysis of HR variability (HF) ratio as primary outcome variables
| df n | df d | F | p | |
|---|---|---|---|---|
| Outcome variable: HR | ||||
| Intercept | 1 | 42,047 | 2,608.3 | <.0001 |
| Age | 1 | 38 | 0.83 | .37 |
| Gender | 1 | 38 | 8.82 | .01 |
| Group | 1 | 38 | 0.71 | .41 |
| Stage | 5 | 42,047 | 3,345.0 | <.0001 |
| Group: Stage | 5 | 42,047 | 63.90 | <.0001 |
| Outcome variable: SDNN | ||||
| Intercept | 1 | 156 | 383.84 | <.0001 |
| Group | 1 | 40 | 0.35 | .56 |
| Stage | 4 | 156 | 9.27 | <.0001 |
| Group: Stage | 4 | 156 | 0.25 | .91 |
| Outcome variable: HF | ||||
| Intercept | 1 | 4,110 | 183.36 | <.0001 |
| Age | 1 | 38 | 0.64 | .43 |
| Gender | 1 | 38 | 3.02 | .09 |
| Group | 1 | 38 | 2.18 | .15 |
| Stage | 5 | 4,110 | 170.80 | <.0001 |
| Group: Stage | 5 | 4,110 | 9.51 | <.0001 |
| Outcome variable: SDNN | ||||
| Intercept | 1 | 156 | 425.73 | <.0001 |
| Group (based on SE of 90%) | 1 | 40 | 5.00 | .03 |
| Stage | 4 | 156 | 9.19 | <.0001 |
| Group: Stage | 4 | 156 | 0.12 | .97 |
HF, high frequency heart rate variability (based on frequency bands from spectral analysis of HRV); HR, heart rate; SDNN, standard deviation of the R‐R interval.
df n and df d denote the numerator and denominator degrees of freedom, respectively. Model coefficients are in Table S1. p values below the significance threshold of .05 are in bold.