Supplementary Material for: Association between Diabetes Mellitus and Contrast-Associated Acute Kidney Injury: A Systematic Review and Meta-Analysis of 1.1 Million Contrast Exposure Patients

<b><i>Background:</i></b> Although diabetes mellitus (DM) has been a common risk factor of contrast-associated acute kidney injury (CA-AKI) for a long time, several current studies showed that DM is not an independent risk factor. Due to this diverse finding, we aim to conduct a systematic review assessing the effect of DM on CA-AKI. <b><i>Methods:</i></b> We searched Ovid Medline, Embase, and Cochrane Database of Systematic Reviews (to June 1, 2020) for studies assessing the association between DM and CA-AKI. Random meta-analysis was performed to derive the pooled estimates of the adjusted odds ratio (OR) and corresponding 95% confidence intervals (CIs). <b><i>Results:</i></b> A total of 84 studies involving 1,136,827 participants were included in this meta-analysis. The presence of DM was associated with an higher risk of CA-AKI (pooled OR: 1.58, 95% CI: 1.48–1.70, <i>I</i>² = 64%). Furthermore, the predictive effect of elevated CA-AKI for was stronger in the subgroup of DM patients with chronic kidney disease (CKD) (OR: 2.33, 95% CI: 1.21–4.51), while the relationship between DM and CA-AKI was not significant in subgroup patients without CKD (OR: 1.12, 95% CI: 0.73–1.72). <b><i>Conclusion:</i></b> This is the first meta-analysis to prove that DM is an independent risk factor of CA-AKI in patients. While the predictive value of DM for CA-AKI in patients with normal kidney function was weakened, more protective treatments are needed in diabetic patients with kidney dysfunction to avoid the occurrence of CA-AKI.