This study provides a direct comparison of the impact of maintained versus down-titrated or discontinued RAASi regimens (including, angiotensin-converting enzyme [ACE] inhibitors, angiotensin receptor blockers [ARBs], angiotensin receptor-neprilysin inhibitors [ARNis], and mineralocorticoid receptor antagonists [MRAs]) on cardiorenal risk following an episode of HK in patients with HF and/or CKD stage 3 or 4, in contemporary routine clinical practice in the US and Japan. This evidence concerns the gene ACE and hydrops fetalis.