Admission, discharge and length of stay¶

Admission and discharge are dates at 1-day resolution, so length of stay is a derived triangular distribution, and discharge days show a weekly pattern rather than rounding.

Data¶

• Admission and discharge dates for 6,388 cases. case 1563 (1900 dates) is excluded.

Method¶

• Checked that discharge minus admission is a whole number of days, and looked at admission lead time and discharge day.

Results¶

• Discharge minus admission is a whole number of days in every case.
• Most patients were admitted 1 day (41%) or 2 days (38%) before surgery; 171 (2.7%) were admitted on the day of surgery.
• Median length of stay is 7 days (IQR 4–11). Twenty-six patients went home on the day of surgery.
• Discharges peak on postoperative day 1 (832) and again on day 7 (669, against 459 on day 6 and 377 on day 8).
• Thirteen stays longer than 115 days (maximum 223 days) are plausible and kept.

Discussion¶

• The day-7 peak probably reflects a weekly discharge routine. It is a real pattern in the dates, not rounding.
• No latent fit is needed. Given a recorded difference of n days, the true length of stay lies anywhere from n − 1 to n + 1 days, a triangular distribution peaked at n.

Limitations¶

• The time of day of admission is unknown within the date.

Tags: from the resolution work