Table 4.

Results of Meta-analysis of medical cost

Study	| SMD	[95% Conf. Interval]		% Weight
Gallagher (2016) [33]	|-2.2e+ 03	−4.7e+ 03	310.072	16.28
Shen (2011) [18]	|-287.300	−439.475	− 135.125	28.23
Gums (1999) [10]	| − 3.1e+ 03	-3.4e+ 03	−2.7e+ 03	27.83
Carter (1997) [8]	|-420.000	− 868.487	28.487	27.66
D + L pooled WMD	|-1.4e+ 03	−3.0e+ 03	155.203	100.00

Heterogeneity chi-squared = 175.82 (d.f. = 3) p = 0.000.

I-squared (variation in WMD attributable to heterogeneity) =98.3%.

Estimate of between-study variance Tau-squared = 2.2e+ 06.

Test of WMD = 0: z = 1.77 p = 0.078.

The significance level of the combined effect quantity test: 0.05.

The significance level of the heterogeneity test: 0.1.

Heterogeneity test: p > 0.1, no heterogeneity was considered; p < 0.1, heterogeneity was considered.