This prospective observational study aims to compare days alive and out of hospital at 30 days (DAOH-30) in patients with poor or good functional capacity undergoing gastrointestinal surgeries. The investigators are testing the hypothesis that patients with good functional capacity will have longer days alive and out of hospital than those with poor.

Days Alive and Out of Hospital (DAOH) is a composite patient-centered outcome that integrates three critical clinical outcomes: death, hospital length of stay, and hospital readmission. It is associated with patient comorbidities, surgical complexity, and postoperative complications.

Evaluation of functional capacity before noncardiac surgery is recommended to identify the perioperative risks. Duke Activity Status Index (DASI) is one of the tools for determining functional capacity; the scores are between 0 and 58,2, and high scores are related to improved capacity. A DASI score of 34 and below was found to be a risk for moderate to severe complications and new disability.

The primary aim is to compare days alive and out of the hospital at 30 days in patients ≤ 34 and above 34 DASI scores. The secondary aims are to evaluate intensive care unit (ICU) need and duration, length of hospital stay, rehospitalization, postoperative complications, morbidity, and mortality in patients with DASI scores ≤ 34 and above 34. Days alive and out of hospital at 90 days will be compared in both groups as a secondary outcome. The investigators will also analyze the possible perioperative factors affecting the days alive and out of the hospital outcome.

Before the operation, the patients will answer the DASI questionnaire in the waiting area of the operating theatres. The patients will be divided into two groups according to the DASI score (Poor functional capacity: ≤ 34 points, good functional capacity: above 34 points).

Patient and surgical characteristics (comorbidities, American Society of Anesthesiologists physical status classification, laboratory values before the operation, frailty index value, American College of Surgeons Risk Calculator outcomes, surgery type, length of operation, intraoperative complications), ICU need and duration will be recorded. Postoperative complications ( cardiovascular, pulmonary, renal, neurologic, surgical, infectious, and wound ), the Postoperative Morbidity Survey (POMS) related morbidity and mortality on the 30th day will be investigated. Length of hospital stay starting with index surgery, rehospitalization and duration of further stays will be recorded. Days Alive and Out of Hospital at 30 days (DAOH-30) will be calculated using mortality, hospital length of stay, and readmissions between the date of the index surgery and the 30th postoperative day. 90th-day mortality and Days Alive and Out of Hospital at 90 days (DAOH-90) will also be investigated.

Inclusion Criteria:

• Patients undergoing intermediate and major upper or lower gastrointestinal surgeries (small intestine, colon, rectal, gastric, esophagus) with a predicted hospital stay of more than 24 hours
• Patients aged 18 and above
• Signed written informed consent
• Reaching all perioperative data

Exclusion Criteria:

• Day case/ambulatory or one overnight hospital stay for minor gastrointestinal and perianal surgeries (hernia repair, hemorrhoidectomy, perianal abscess and fistula, appendectomy)
• Hepatobiliary surgeries (hepatectomy, pancreas and gallbladder surgeries)
• Patients aged below 18
• Not signed written informed consent
• Missing perioperative data

Patients undergoing gastrointestinal surgeries at Istanbul Medical Faculty in Istanbul-Turkey will be selected for the study population. Istanbul Medical Faculty is a tertiary center university hospital with approximately 25.000 surgeries annually.