Table 6

Multivariable meta-regressions

ModeratorsP valueMarginal R2Within-articles varianceBetween-articles variance
τ2Adjusted I2τ2Adjusted I2
Without moderators3.6%56.6%2.8%42.9%
TMZ concentration and treatment duration<0.00142.1%1.7%
(1.5% to 1.9%)
30.9%3.7%
(2.7% to 5.2%)
68.5%
TMZ concentration, treatment duration and mediums’ glucose level<0.00145.4%1.7%
(1.5% to 1.9%)
31.9%3.5%
(2.6% to 5.0%)
67.4%
TMZ concentration, treatment duration and articles reporting quality<0.00144.1%1.7%
(1.5% to 1.9%)
31.6%3.6%
(2.6% to 5.0%)
67.8%
TMZ concentration, treatment duration, mediums’ glucose level and articles reporting quality<0.00145.9%1.7%
(1.5% to 1.9%)
32.0%3.5%
(2.5% to 5.0%)
67.4%
  • Multivariable random-effects three-level meta-regressions with the raw data the effects were calculated with as first level, the reported effects as second level and the articles the effects were reported in as third level. P value is given for the test of the moderator. Marginal R2 indicates the regression model fit;69 τ2: estimator of the variance of true effects; adjusted I2: proportion of within-articles and between-articles variance of true effects, respectively, of the total observed variance including sampling error with the indicated moderators. τ2 estimator: restricted-maximum likelihood. For all multivariable meta-regressions, 644 effects in 101 articles were included.

  • TMZ, temozolomide.