Table 4

 Association between characteristics of the analysis and the assessment of publication bias

VariableTotal (n = 225)Assessment of publication bias n (%)RR (95% CI)
Heterogeneity ascertainment
    Yes18724 (12.8)4.88 (0.68 to 35.0)
    No381 (2.6)1(ref)
Presence of heterogeneity
    Yes12820 (15.6)3.03 (1.18 to 7.79)
    No975 (5.2)1(ref)
Justification of heterogeneity
    Yes21123 (10.9)0.76 (0.20 to 2.91)
    No142 (14.3)1(ref)
Discussion of heterogeneity
    Yes18919 (10.0)0.60 (0.26 to 1.41)
    No366 (16.7)1(ref)
Statistical significance of the pooled estimate
    Yes15120 (13.2)1.96 (0.77 to 5.02)
    No745 (6.8)1(ref)
Specification of the statistical model (random or fixed effects)
    Yes17122 (12.9)2.32 (0.72 to 7.44)
    No543 (5.6)1(ref)