Comparison between preterm and full-term
The first analysis for comparison included all studies with a full-term control group (18 studies) and a preterm group. The sample size was 28557 preterm children and 183414 full-term children. The preterm group is more likely to have DCD with an overall risk ratio of 2.2 (95% CI 1.77 – 2.79) than full-term controls. High heterogeneity was observed between the studies (I2 = 90%). The analyses are presented in Figure 5.
When comparing the groups by gestational age (extremely, very, and moderate/late preterm) with full-term, the results showed an increased risk as gestational age decreased. Extremely preterm children are at 3.78 (95% CI 2.38 – 6.02) more likely to have DCD compared to full-term; very preterm are at risk 2.72 (95% CI 1.90 – 3.91); and moderate/late preterm are at risk 1.58 (95% CI 1.27 – 1.96). The analyses are presented in Figure 6.
Analyses from comparison were also performed by assessment tool and different cut-off criteria for DCD; we still found that premature children are more likely to have DCD. Six studies had a control group and used 5th percentile cut-off criteria with MABC; the risk ratio in the meta-analysis was 3.74 (95% CI 2.07 – 6.76). Four studies used 15th percentile cut-off criteria with MABC, and the risk ratio was 2.67 (95% CI 1.64 – 4.37). Six studies with a control group used DCDQ, and the risk ratio was 1.58 (95% CI 1.16 – 2.15). Results are presented in Figure 7. Only one study with a control group used another cut-off criteria and then was excluded from this analysis.47 Further, 4 studies used different tool assessments and were also excluded from this analysis.22,25,30,43