Table 2. Subgroup analysis serum creatinine.

	Δ baseline studies					Control group studies
subgroup	n	MD	95% CI	P-value	I2%	n	MD	95% CI	P-value	I2%
overall	11	0.43	[0.18, 0.68]	0.001	99	18	0.33	[0.17, 0.48]	0.000	96
species
dog	0	NA	NA	NA	NA	0	NA	NA	NA	NA
pig	6	0.53	[0.33, 0.73]†	0.000	94	5	0.41	[0.16, 0.66]	0.001	74
rabbit	2	NA	NA	NA	NA	2	NA	NA	NA	NA
rat	3	0.06	[-0.20, 0.32]†	0.654	93	11	0.20	[0.04, 0.36]	0.015	76
sex
female	3	0.68	[0.29, 1.07]	0.001	97	2	NA	NA	NA	NA
male	4	0.25	[-0.08, 0.59]	0.134	79	6	0.09	[-0.12, 0.31]	0.384	26
mixed	2	NA	NA	NA	NA	8	0.29	[0.10, 0.48]	0.003	96
NR	2	NA	NA	NA	NA	2	NA	NA	NA	NA
pnp pressure
low	0	NA	NA	NA	NA	1	-0.01	[-0.69, 0.67]	0.977	0
medium	7	0.32	[-0.06, 0.70]	0.097	99	9	0.26	[0.03, 0.50]	0.024	96
high	4	0.62	[0.12, 1.12]	0.015	99	8	0.45	[0.19, 0.71]	0.001	97
gas type
CO2	9	0.44	[0.10, 0.77]	0.011	99	10	0.35	[0.13, 0.58]	0.002	96
other	2	NA	NA	NA	NA	8	0.29	[0.06, 0.53]	0.016	96
pnp duration
1–30 min	2	NA	NA	NA	NA	0	NA	NA	NA	NA
31–60 min	2	NA	NA	NA	NA	9	0.86	[0.22, 1.49]	0.008	85
61–120 min	4	0.66	[-0.17, 1.49]	0.120	72	6	0.74	[-0.07, 1.56]	0.075	70
121–240 min	5	1.21	[0.43, 1.99]	0.002	81	5	0.59	[-0.30, 1.47]	0.195	79
>240 min	4	1.61	[0.82, 2.40]	0.000	87	4	1.17	[0.28, 2.06]	0.010	71

After correction for multiple testing of 4 variables, P<0.012 was considered significant for Δ baseline studies. After correction for multiple testing of 5 variables, P<0.010 was considered significant for control group studies.

^†significant difference between these two subgroups;

n = number of comparisons in analysis; CI = confidence interval; pnp = pneumoperitoneum; NA = not analyzed due to insufficient data