Table 2.

Sensitivity Analysis for Primary Outcome, Mean Difference in Change in Creatinine

Subgroups of Studies	Studies Included	Estimated Mean Difference in ΔCr (mg/dl)	95% CI	P Homogeneity*
Studies included in meta-analysis	1–4,6–9	−0.27	−0.43 to −0.11	<.01
High baseline Cr (Cr ≥2.0)	3,4,8,9	−0.36	−0.63 to −0.09	<.01
Low baseline Cr (Cr<2.0)	1,2,6,7	−0.18	−0.36 to 0.00	.02
High mean contrast volume (vol ≥150 ml)	2,6,7	−0.20	−0.45 to 0.06	.01
Low mean contrast volume (vol<150 ml)	1,3,4,9	−0.38	−0.62 to −0.14	<.01
High mean percentage with diabetes (≥50%)	3,6	−0.46	−0.59 to −0.33	.29
Low mean percentage with diabetes (<50%)	1,2,7–9	−0.20	−0.40 to 0.00	<.01
Studies using 0.9 NS for hydration	1,2	−0.15	−0.31 to 0.01	.96
Studies using 0.45 NS for hydration	3,4,6–9	−0.31	−0.51 to −0.10	<.01
All studies reporting mean difference†	1–4,6–10,12,15	−0.28	−0.43 to −0.13	<.01
Randomized, placebo-controlled†	1,3,4,6,9	−0.39	−0.56 to −0.22	.01
Studies using oral NAC formulation	1,3–9	−0.29	−0.46 to −0.11	<.01
Studies using intra-arterial contrast	1–8	−0.22	−0.38 to −0.06	<.01

^*Heterogeneity is present when P<.1.

^†Analysis includes excluded studies.

Cr, creatinine; NAC, N-acetylcysteine; NS, normal saline; CI, confidence interval.

Mean difference change in creatinine, NAC versus placebo. Calculations were done using a random effects model. Study numbers are referenced from Table 1. The quality of studies was not included in the sensitivity analysis because only 1 study fit criteria for high quality. Studies using high doses of oral NAC were not analyzed because only 1 study fit criteria for high-dose oral NAC.