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Table 6 Average correlations between reference variables and PMMSA scores across time points

From: Psychometric performance of the Primary Mitochondrial Myopathy Symptom Assessment (PMMSA) in a randomized, double-blind, placebo-controlled crossover study in subjects with mitochondrial disease

 

4FS

Item 1

Tiredness at rest

Item 2

Tiredness during activities

Item 3

Muscle weakness at rest

Item 4

Muscle weakness during activities

Item 5

Balance problems

Item 6

Vision problems

Item 7

Abdominal discomfort

Item 8

Muscle pain

Item 9

Numbness

Item 10

Headache

Height

− 0.15

− 0.28

− 0.03

− 0.18

− 0.01

0.07

0.02

− 0.05

− 0.06

0.18

− 0.17

Weight

− 0.01

− 0.04

0.11

− 0.07

0.02

− 0.04

− 0.03

0.00

0.41

0.39

0.00

BMI

0.05

0.06

0.08

0.01

0.03

− 0.06

0.01

0.02

0.41

0.29

0.09

Reference measures

Neuro-QoL Fatigue

0.69

0.63

0.67

0.62

0.67

0.35

0.01

0.36

0.31

0.14

0.25

PhGA

0.28

0.36

0.32

0.38

0.41

0.34

0.16

0.36

0.25

0.16

0.26

PGA

0.39

0.27

0.27

0.29

0.33

0.30

0.02

0.03

0.11

0.20

− 0.03

6MWT PRO fatigue (pre)

0.43

0.43

0.39

0.44

0.43

0.15

− 0.15

0.30

0.43

0.22

0.14

6MWT PRO dyspnea (pre)

0.26

0.30

0.19

0.32

0.18

0.21

0.02

0.04

0.11

0.06

− 0.13

6MWT distance

− 0.13

− 0.06

− 0.08

− 0.14

− 0.19

− 0.32

− 0.17

0.16

0.00

− 0.18

0.19

6MWT PRO fatigue (post)

0.33

0.35

0.30

0.32

0.33

0.09

0.02

0.05

0.18

− 0.05

0.08

6MWT PRO dyspnea (post)

0.24

0.27

0.18

0.24

0.22

0.26

0.12

− 0.12

− 0.04

− 0.16

− 0.02

3TUG time to completion

0.11

0.01

0.08

0.08

0.21

0.39

0.39

− 0.03

0.11

0.39

− 0.11

SARA

0.25

0.22

0.18

0.30

0.27

0.50

0.15

− 0.04

− 0.12

0.22

− 0.14

  1. All correlations except those involving the Neuro-QoL fatigue scale are based on the average of coefficients generated across five time points including Study Visits 2 (N = 30), 3 (N = 29), 4 (N = 30), 5 (N = 28) and 6 (N = 28). For correlations involving the Neuro-QoL fatigue scale, scores were generated from an additional nurse home visit at Week 6 (N = 27). In each instance, PMMSA scores are based on weekly averages
  2. 3TUG = Triple Timed Up and Go test; 6MWT = six-minute walk test; Neuro-QoL = Quality of Life in Neurological Disorders; PGA = Patient Global Assessment; PhGA = Physician Global Assessment; PMMSA = Primary Mitochondrial Myopathy Symptom Assessment; SARA = Scale for the Assessment and Rating of Ataxia. PhGA, PGA, and 6MWT PRO Borg items are assessed using Spearman’s correlations; all other reported correlations are Pearson’s