Table 3.
abcd Intercorrelation of the measurements for t1, t2, differences (Δ) and t2 + Δ
| (a) Spearman correlations (rho) for t1; n = 395 | ||||||
| t1 | FTF-CROM | EQ-VAS | EQ5D TTO | NPRS | HAQ | ODI |
| FTF-CROM | – | |||||
| EQ5D health (EQ-VAS) | −0.16** | – | ||||
| EQ5D TTO | −0.19** | 0.39** | – | |||
| NPRS | 0.18** | −0.36** | −0.58** | – | ||
| HAQ | 0.30** | −0.37** | −0.66** | 0.44** | – | |
| ODI | 0.22** | −0.43** | −0.68** | 0.58** | 0.69** | – |
| Mean PROMs | 0.27** | 0.64** | 0.83** | 0.77** | 0.77** | 0.85** |
| Overall MQO | 0.86** | 0.44** | 0.55** | 0.52** | 0.62** | 0.59** |
| Linear regression with constant (beta coefficients) for t1 scores (predictor FTF t1; R2 = 0.098; p = 0.000***; c = 18.371): −0.073*EQ-VAS t1 + −0.029*EQ5D TTO t1 + 0.074*NPRS t1 + 0.252*HAQ t1 + −0.036*ODI t1 | ||||||
| (b) Spearman correlations (rho) for t2; n = 395 | ||||||
| t2 | FTF-CROM | EQ-VAS | EQ5D TTO | NPRS | HAQ | ODI |
| FTF-CROM | – | |||||
| EQ5D health (EQ-VAS) | −0.17** | – | ||||
| EQ5D TTO | −0.29** | 0.45** | – | |||
| NPRS | 0.21** | −0.42** | −0.67** | – | ||
| HAQ | 0.36** | −0.41** | −0.73** | 0.55** | – | |
| ODI | 0.27** | −0.46** | −0.77** | 0.64** | 0.73** | – |
| Mean PROMs | 0.32** | 0.73** | 0.84** | 0.80** | 0.80** | 0.85** |
| Overall MQO | 0.84** | 0.53** | 0.65** | 0.57** | 0.68** | 0.65** |
| Linear regression with constant (beta coefficients) for t2 scores (predictor FTF t2; R2 = 0.139; p = 0.000***; c = 16.653): −0.029*EQ-VAS t2 + −0.082*EQ5D TTO t2 + 0.022*NPRS t2 + 0.254*HAQ t2 + 0.037*ODI t2 | ||||||
| (c) Spearman correlations (rho) for differences (t2 − t1; Δ); n = 395 | ||||||
| Difference; Δ (D = t2 − t1) | FTF-CROM | EQ-VAS | EQ5D TTO | NPRS | HAQ | ODI |
| FTF-CROM | – | |||||
| EQ5D health (EQ-VAS) | 0.01 | – | ||||
| EQ5D TTO | 0.02 | 0.11* | – | |||
| NPRS | 0.05 | −0.12* | −0.38** | – | ||
| HAQ | −0.00 | −0.08 | −0.34** | 0.24** | – | |
| ODI | 0.02 | −0.17** | −0.40** | 0.37** | 0.34** | – |
| Mean PROMs | 0.05 | 0.54** | 0.67** | 0.66** | 0.49** | 0.62** |
| Overall MQO | 0.60** | 0.42** | 0.49** | 0.55** | 0.36** | 0.49** |
| Linear regression with constant (beta coefficients) for difference scores (predictor FTF difference; R2 = 0.003; p = 0.964; c = −4.528): −0.006*EQ-VAS D + 0.026 EQ5D TTO D + 0.023*NPRS D + 0.006*HAQ D + 0.037*ODI D | ||||||
| (d) Spearman correlations (rho) for performance score (t2 + Δ; t2D); n = 395 | ||||||
| Performance scores | FTF-CROM | EQ-VAS | EQ5D TTO | NPRS | HAQ | ODI |
| FTF-CROM | – | |||||
| EQ5D health (EQ-VAS) | −0.11* | – | ||||
| EQ5D TTO | −0.15** | 0.22** | – | |||
| NPRS | 0.13** | −0.26** | −0.48** | – | ||
| HAQ | 0.28** | −0.26** | −0.36** | 0.40** | ||
| ODI | 0.23** | −0.33** | −0.50** | 0.53** | 0.24** | – |
| Mean PROMs | 0.23** | 0.68** | 0.64** | 0.73** | 0.63** | 0.75** |
| Overall MQO | 0.74** | 0.52** | 0.51** | 0.56** | 0.56** | 0.63** |
| Linear regression with constant (beta co + B2:H48ficients) for perf. scores (predictor FTF t2D; R2 = 0.093; p = 0.000***; c = 7.709): 0.001*EQ-VAS t2D + −0.028*EQ5D TTO t2D + −0.020*NPRS t2D + 0.191*HAQ t2D + 0.140*ODI t2D | ||||||
CROM-FTF, mean of PROMs and the overall medical outcome (MQO; mean of PROMs and CROM-FTF) are highlighted in bold
Although the level of significant correlations (*, ** or bold) was reached for multiple measures (all p < 0.05*)—with the exception of the difference values—the Spearman’s rho of the FTF with the PROMs was very weak to weak (rho = 0.00–0.36). A rho = 0.10 corresponds to a small effect, rho of 0.30 correspond to a middle effect, and rho values > 0.50, to a large effect size [36]