Overall, there was a non-linear U-shaped change in the proportion of respiratory-related conditions (red) as the readmission diagnosis with an inflection point at day 8 after discharge. The proportion of cardiac-related conditions (yellow) had a similar non-linear pattern with inflection points at day 6 and day 22. By contrast, the proportion of the other conditions (blue) had a different pattern with an inflection point at day 6. Compared to patients aged 65-84 years, those aged ≥85 years appeared to have a greater magnitude of changes, with delayed inflection points for the other conditions (at days 3 and 12).
Marks (×) indicate the infliction points.