Coefficients of different linear regression models and application to testing data
| Ross et al. [14] mean (r=0.82) | p-value | Ross et al. [14] (r=0.59) | p-value | Miyamoto et al. [16] (r=0.68) | p-value | Zapico et al. [17] (R2=0.48) | p-value | New model (R2=0.48) | p-value | |
| Observations n | 1038 | 1083 | 27 | 82 | 194 | |||||
| Intercept | 4.948 | 4.682 | 4.213 | −21.626 | 1.83 | 0.248 | ||||
| 6MWD, m | 0.023 | 0.025 | 0.026 | 0.026 | <0.001 | 0.031 | <0.001 | |||
| Sex | 4.103 | 0.002 | ||||||||
| Height, cm | 0.174 | 0.043 | ||||||||
| Weight, kg | −0.071 | 0.02 | −0.023 | 0.22 | ||||||
| HRR, bpm | −0.015 | 0.047 | ||||||||
| Applied to testing dataset | ||||||||||
| SEE, mL/min/kg | 3.03 | 3.22 | 4.36 | 3.08 | ||||||
| SEE% mean | 19% | 20% | 27% | 19% | ||||||
| Ability to classify to low risk (V′O2max >15 mL/min/kg) | ||||||||||
| Sensitivity | 0.96 | 0.96 | 0.91 | 0.69 | ||||||
| Specificity | 0.23 | 0.23 | 0.22 | 0.78 | ||||||
| PPV | 0.63 | 0.63 | 0.63 | 0.82 | ||||||
| NPV | 0.80 | 0.80 | 0.64 | 0.64 |
r from correlation between maxima oxygen uptake (V′O2max) and 6-min walk distance (6MWD); R2 from linear regression of V′O2max against 6MWD. HRR: heart rate response in 6-min walk test (heart rate at maximal exercise – heart rate at rest); NPV: negative predictive value; PPV: positive predictive value; SEE: standard error of the estimate; SEE% mean: SEE as percentage of mean peak oxygen uptake. All coefficients, p-values and R2 for Ross et al. [14], Miyamoto et al. [16] and Zapico et al. [17] are copied from the original publications.