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Stratos LV/LV-T Technical Manual  57 
Table 15: Composite of Six Minute Walk Test and QOL 
(Effectiveness) 
Category 
Study Group 
(N = 74) 
Mean 
± SE 
Control Group 
(N = 38) 
Mean 
± SE 
P-value
*
 
Distance 
Walked at 
Baseline 
310.51 ± 10.89 
288.76 ± 15.37 
0.249 
Distance 
Walked at 
Six-Months 
340.77 ± 12.32 
301.84 ± 17.02 
0.067 
∆ Distance 
Walked 
30.26 ± 10.40 
17.27% ± 5.59% 
13.08 ± 13.05 
8.71% ± 5.26% 
0.322 
0.326 
QOL Score at 
Baseline 
44.39 ± 2.78  
45.53 ± 4.13  
0.817 
QOL Score at 
Six-Months 
28.68 ± 2.66  
33.95 ± 4.35  
0.279 
∆ in QOL 
Score† 
15.72± 2.83 
19.08% ± 12.21%  
11.58 ± 3.45 
-13.42% ± 
34.54% 
0.376 
0.281 
Composite 
Rate
 
18.18% ± 7.07%  -2.36% ± 17.73%
0.030 
 
                                                      
 
*
 The calculated p-values are associated with a Student's t-test (2-sided) of the 
equality of means in the two groups, except for the p-value of the composite rate, 
which is associated with a test of equivalence (non-inferiority). 
  ∆  in QOL Score is calculated as the average of the individual differences 
between Baseline and Six-Months for each patient. Negative values for mean ∆ 
QOL in percent are possible when positive mean values for absolute changes in 
QOL are recorded.  In some cases, small, negative changes in absolute QOL 
scores resulted in relatively large percentage changes. 
 The Composite Rate (=(∆ Distance Walked (%) + ∆ QOL Score (%)) / 2) is 
calculated for each patient and then averaged to obtain the Composite Rates.  
For all calculations, a positive number represents improvement from Baseline to 
Six-Months.