ACE and heart failure: AKI patients versus non-AKI ones were significantly older (median age 76.0 vs. 71.0, p < 0.001) and had more comorbidities, especially previous renal diseases, heart failure, coronary artery disease, and hypertension; they also significantly more often used diuretics, angiotensin receptor blockers (ARBs), and angiotensin-converting enzyme inhibitors (ACE-Is).