Previous some small studies also supported the evidences that COX-2 inhibitors spared more renal hemodynamic function than nonselective NSAIDs did,17–19 although some studies did not.20,21 Nevertheless, our results from 6199 AKI cases did provide a more robust basis for clarifying the controversy about whether COX-2 inhibitors were responsible for AKI events on a national scale. Here, PTGS2 is linked to acute kidney injury.