Outcome

Subgroup

Studylevel covariate(s) included into the metaregression

Heterogeneity assessment


Covariate(s) selected

pvalue*

Cochran’s Q (df)

pvalue (Q test)

I^{2} (%)

Betweenstudy variance^{e}

R^{2} (%)^{f}


DMD prevalence

Males only (15 studies)

None (randomeffects MA)

–

856.4531 (df = 14)

< 0.0001

98.46%

0.4741

–

Continent^{a}

0.2027

450.7452 (df = 12)

< 0.0001

97.90%

0.3857

18.65%

Study year (begin) + Study duration

0.4195

632.8951 (df = 12)

< 0.0001

97.89%

0.4227

10.84%

Study design^{c}

0.6429

572.9228 (df = 12)

< 0.0001

98.40%

0.4452

6.10%

DMD birth prevalence

All (27 studies)

None (randomeffects MA)

–

82.0309 (df = 26)

< 0.0001

89.79%

0.1646

–

Continent^{b}

0.9308

74.7046 (df = 23)

< 0.0001

88.90%

0.1619

1.64%

Study year (begin) + Study duration

0.0012

60.8329 (df = 23)

< 0.0001

83.13%

0.0905

45.02%

Study design^{d}

0.3189

78.8714 (df = 24)

< 0.0001

87.51%

0.1483

9.90%

 MA Metaanalysis, I^{2} Measure of inconsistency, df Degrees of freedom referred to the Cochran’s Q test
 *Pvalues from omnibus Waldtype test of parameters (i.e. studylevel covariates included into the model)
 ^{a}Continents were regrouped as follows: America North (US and Canada) (4 studies), Europe North/Centre/East (8 studies), Others (Asia East and Africa South) (3 studies)
 ^{b}Continents were regrouped as follows: America North (US and Canada) (4 studies), Asia East and Australia/NewZealand (4 studies), Europe Centre/East/South (13 studies), Europe North (6 studies)
 ^{c}Study designs were regrouped as follows: Observational cohort (3 studies), Retrospective cohort/chartreview/crosssectional (9 studies), epidemiological survey (3 studies)
 ^{d}Study designs were regrouped as follows: Crosssectional (10 studies), Prospective cohort and survey (8 studies), Retrospective cohort/chartreview (9 studies)
 ^{e}Total and residual betweenstudy variance: the overall heterogeneity corresponds to the total betweenstudy variance estimated from randomeffects MA whereas the residual heterogeneity corresponds to between studyvariance explained by the studylevel covariates included into metaregression model
 ^{f}R^{2} is the proportion of the overall heterogeneity (i.e. the total betweenstudy variance) which is “explained” (i.e. reduced) by the effect of the included studylevel covariate