After adding diuretics, insulin and angiotensin converting enzyme inhibitors to the to the statistical model (containing age, NIHSS score, atrial fibrillation, pre-stroke cognitive decline, pre-stroke disability and infections), the odds ratio of delirium in patients with higher apathy score was 1.80 (95% CI: 1.00–3.24, P = 0.049). This evidence concerns the gene ACE and delirium.