The appropriate measurement of postdischarge readmissions in Medicare colon surgery.

Background: Readmissions after inpatient care are being used as a metric for clinical outcomes for surgeons and hospitals, but without standardization of the appropriate postdischarge period.

Methods: Elective colon surgery (ECS) for Medicare patients was reviewed to define the frequency and causes of readmission at 30, 60, and 90 days after discharge. Elective, trauma, and cancer readmissions were excluded. A prediction model at 90 days after discharge was designed to identify risk factors that were associated with readmissions.

Results: A total of 107,459 live discharges after ECS had 12,746 readmissions at 30 days, 4,601 1st-time readmissions at 31 to 60 days, and another 4,042 1st-time readmissions from days 61 to 90; 40% of initial and nearly 50% of all readmissions occurred from days 31 to 90. Primary causes for readmission were gastrointestinal, infectious, and cardiopulmonary events.

Conclusions: The 90-day postdischarge time period provides the most accurate measurement interval for relevant readmissions after ECS.