Table 4

Representativeness of the pooled effects of studies providing data for the IPD study and those not providing data. Two stage analysis; SMT vs recommended therapies

Representativeness Number of studies Difference in effect (CI 95%) Test of heterogeneity Prediction Interval
Outcome I2 P-value
Pain Mean difference
Combined pain score one month
All eligible studies 16 -2.4 (-4.9; 0.1)
 66%
 <0.001 -2.4 (-11.6; 6.9)
Studies providing data 10
 -2.5 (-5.9; 0.9)
 75%
 <0.001 -2.7 (-13.8;8.8)
Studies not providing data 6
 -2.2 (-6.1; 1.7) 55%
 0.02
 -2.218 (-12.9; 8.5)
Combined pain score three months
All eligible studies 14 -3.1 (-7.0; 0.8)
 80%
 <0.001 -3.1 (-18.6; 12.4)
Studies providing data 9
 -5.9 (-11.4; -0.5) 86%
 <0.001 -5.9 (-25.0; 13.0)
Studies not providing data 5
 1.1 (-2.7; 4.9) 29%
 0.196
 1.1 (-7.4; 9.6)
Combined pain score six months
All eligible studies 13
 -4.1 (-6.7;-1.6)
 66%
 <0.001 -4.1 (-13.5; 5.2)
Studies providing data 8
 -4.8 (-8.9; -0.6)
 72%
 0.001
 -4.8 (-17.8;8.3)
Studies not providing data 5
 -3.5 (-7.0; -0.1) 61%
 0.009
 -3.5 (-13.8; -6.4)
Combined pain score twelve months
All eligible studies 12
 -1.8 (-4.8; 1.3)
 71%
 <0.001 -1.8 (-12.5; 9.0)
Studies providing data 10
 -2.1 (-6.5; 2.2)
 79%
 <0.001 -2.1 (-16.8; 12.5)
Studies not providing data 2
 -0.9 (-3.5; 1.8) 0%
 0.6
 -0.9 (-6.7; 5.0)
Functional status Difference in Z-score
Combined Functional Status
One month
All eligible studies 13 -0.2 (-0.3; -0.0) 49% 0.014 -0.2 (-0.6; 0.3)
Studies providing data 9 -0.3 (-0.5; -0.0) 65% 0.003 -0.3 (-1.0; 0.4)
Studies not providing data 4 -0.1 (-0.2; 0.0) 0% 0.739 -0.1 (-0.2; 0.1)
Combined Functional Status three months
All eligible studies 15 -0.1 (-0.2; 0.1) 75% <0.001 -0.1 (-0.8; 0.7)
Studies providing data 11 -0.2 (-0.4; 0.0) 79% <0.001 -0.2 (-0.9;0.6)
Studies not providing data 4 0.2 (-0.1; 0.4) 45% 0.089 0.2 (-0.5; 0.8)
Combined Functional Status six months
All eligible studies 13 -0.1 (-0.2; 0.0) 56% 0.002 -0.1 (-0.6; 0.4)
Studies providing data 9 -0.2 (-0.4; -0.0) 69% 0.001 -0.2 (-0.9; 0.5)
Studies not providing data 4 0.0 (-0.1; 0.1) 0% 0.778 0.0 (-0.1; 0.2)
Combined Functional Status twelve months
All eligible studies 13 -0.2 (-0.3; 0.1) 72% <0.001 -0.2 (-0.7; 0.4)
Studies providing data 10 -0.2 (-0.4; 0.1) 79% <0.001 -0.2 (-0.9; 0.6)
Studies not providing data 3 -0.1 (-0.3; 0.1) 43% 0.132 -0.1 (-0.7; 0.5)

CI = confidence interval; I2 = I2 statistic, which is the percentage of total variance that can be explained by heterogeneity, and 25% is considered low, 50% moderate, and 75% high heterogeneity.