Table 2.
Construct Validity: Cross-sectional association1 of 4-meter gait speed (m/sec) with mobility and physical function (convergent validity) and mental health measures (discriminant validity)
| Convergent Validity: Correlation with Measures of Physical Function | ||||||||
|
Follow-up, in months |
Study | N |
6 minute walk test |
FPI Survey |
No. ADL dependencies |
No. IADL dependencies |
SF-36 PF domain2 |
EQ-5D Mobility3 |
| Pooled† | ALTOS | 296–310 | 0.62 (<0.001) | 0.50 (<0.001) | -- | -- | 0.58 (<0.001) | −0.44 (<0.001) |
| 6 mo. | ALTOS | 153–158 | 0.56 (<0.001)4 | 0.49 (<0.001) | 0.58 (<0.001) | −0.41 (<0.001) | ||
| 12 mo. | ALTOS | 143–152 | 0.67 (<0.001)4 | 0.50 (<0.001) | 0.58 (<0.001) | −0.45 (<0.001) | ||
| Pooled† | ICAP | 293–313 | 0.37 (<0.001) | -- | −0.27 (<0.001) | −0.43 (<0.001) | 0.57 (<0.001) | −0.42 (<0.001) |
| 36 mo. | ICAP | 92–96 | 0.37 (<0.001) | −0.19 (0.059) | −0.35 (<0.001) | 0.55 (<0.001) | −0.30 (0.003) | |
| 48 mo. | ICAP | 98–107 | 0.47 (<0.001) | −0.30 (0.002) | −0.38 (<0.001) | 0.54 (<0.001) | −0.43 (<0.001) | |
| 60 mo. | ICAP | 103–110 | 0.28 (0.005) | −0.39 (<0.001) | −0.57 (<0.001) | 0.64 (<0.001) | −0.51 (<0.001) | |
| Discriminant Validity: Correlation with Measures of Mental Health | ||||||||
|
Follow-up, in months |
Study | N |
HADS Anxiety Symptoms |
IES-R PTSD Symptoms |
SF-36 MH domain2 |
EQ-5D Anxiety3 |
||
| Pooled† | ALTOS | 309–310 | −0.17 (0.003) | −0.23 (<0.001) | 0.20 (<0.001) | −0.18 (0.002) | ||
| 6 mo. | ALTOS | 157–158 | −0.18 (0.022) | −0.24 (0.003) | 0.24 (0.002) | −0.22 (0.005) | ||
| 12 mo. | ALTOS | 150–152 | −0.15 (0.060) | −0.22 (0.006) | 0.15 (0.093) | −0.16 (0.053) | ||
| Pooled† | ICAP | 311–313 | −0.25 (<0.001) | −0.29 (<0.001) | 0.26 (<0.001) | −0.19 (<0.001) | ||
| 36 mo. | ICAP | 95–96 | −0.19 (0.066) | −0.27 (0.008) | 0.20 (0.050) | −0.13 (0.201) | ||
| 48 mo. | ICAP | 107 | −0.20 (0.044) | −0.22 (0.026) | 0.25 (0.011) | −0.09 (0.371) | ||
| 60 mo. | ICAP | 109–110 | −0.36 (<0.001) | −0.39 (<0.001) | 0.34 (<0.001) | −0.34 (<0.001) | ||
Abbreviations: FPI: Functional Performance Inventory; ADL: Activities of Daily Living; IADL: Instrumental Activities of Daily Living, SF-36: Short Form-36.
Clustered robust standard errors were calculated for data pooled across time points to account for repeated measures.
Based on Pearson correlations except for EQ-5D subscales, which used Spearman correlations. Moderate-to-strong associations with physical health measures (r >0.40) expected for convergent validity; weak associations with mental health measures (r ≤0.30) expected for discriminant validity.
SF-36 physical function (PF) and mental health (MH) subscales (transformed version, score range:0–100, higher = better functioning).
EQ-5D subscales (Likert rating scales of 0, 1, and 2, higher = worse health).
Previously reported in Chan et al.(2015)24