Table 3.
Bivariate associations between the maximum value of steps and demographic and clinical variables, both objectively detected and reported by the patient. The heatmap (below) graphically depicts the direction of the correlation, with red tones trending towards a stronger association, negative or positive (± 1). Correlations are computed using the Spearman’s q.
| Sex | Age | EDSS | MWD | T25FW | PDDS | FSS | PHQ9 | PRIMUS | 2MW | MaxSteps | |
|---|---|---|---|---|---|---|---|---|---|---|---|
| Sex | 1 | ||||||||||
| Age | −0.302 | 1 | |||||||||
| EDSS | −0.088 | 0.568 | 1 | ||||||||
| MWD | 0.0320 | −0.458 | −0.912 | 1 | |||||||
| T25FW | 0.0557 | 0.665 | 0.466 | −0.402 | 1 | ||||||
| PDDS | −0.198 | 0.608 | 0.398 | −0.307 | 0.647 | 1 | |||||
| FSS | −0.2944 | 0.306 | 0.187 | −0.250 | 0.264 | 0.419 | 1 | ||||
| PHQ9 | −0.008 | 0.064 | 0.010 | −0.228 | −0.045 | 0.014 | 0.743 | 1 | |||
| PRIMUS | −0.208 | 0.027 | 0.167 | −0.276 | 0.110 | 0.252 | 0.831 | 0.830 | 1 | ||
| 2MW | 0.213 | −0.635 | −0.535 | 0.578 | −0.669 | −0.459 | −0.112 | 0.158 | 0.043 | 1 | |
| MaxSteps | 0.301 | −0.539 | −0.270 | 0.267 | −0.400 | −0.650 | −0.473 | −0.237 | −0.357 | 0.429 | 1 |
| Heatmap | |||||||||||
| 0–0.1 Absent |
0.2–0.3 Low |
0.4–0.5 Moderate |
0.6–0.7 Strong |
0.8–0.9 Very strong |
1 Perfect |
||||||
| 0–(−0.1) Absent |
(−0.2)–(−0.3) Low |
(−0.4)–(−0.5) Moderate |
(−0.6)–(−0.7) Strong |
(−0.8)–(−0.9) Very strong |
−1 Perfect |
||||||
PRIMUS: patient-reported outcome indices for multiple sclerosis, EDSS: expanded disability status scale, FSS: fatigue severity scale, MaxSteps: maximum daily steps, MWD: maximum walking distance, PDDS: patient-determined disease steps, PHQ9: nine-item patient health questionnaire, 2MW: two-minute walking test; T25FWT: timed 25-foot walk test. Bold characters are statistically significant.