Validation of days at home as an outcome measure after surgery: a prospective cohort study in Australia

OBJECTIVE: To evaluate ‘days at home up to 30 days after surgery’ (DAH(30)) as a patient-centred outcome measure. DESIGN: Prospective cohort study. DATA SOURCE: Using clinical trial data (seven trials, 2109 patients) we calculated DAH(30) from length of stay, readmission, discharge destination and death up to 30 days after surgery. MAIN OUTCOME: The association between DAH(30) and serious complications after surgery. RESULTS: One or more complications occurred in 263 of 1846 (14.2%) patients, including 19 (1.0%) deaths within 30 days of surgery; 245 (11.6%) patients were discharged to a rehabilitation facility and 150 (7.1%) were readmitted to hospital within 30 days of surgery. The median DAH(30) was significantly less in older patients (p<0.001), those with poorer physical functioning (p<0.001) and in those undergoing longer operations (p<0.001). Patients with serious complications had less days at home than patients without serious complications (20.5 (95% CI 19.1 to 21.9) vs 23.9 (95% CI 23.8 to 23.9) p<0.001), and had higher rates of readmission (16.0% vs 5.9%; p<0.001). After adjusting for patient age, sex, physical status and duration of surgery, the occurrence of postoperative complications was associated with fewer days at home after surgery (difference 3.0(95% CI 2.1 to 4.0) days; p<0.001). CONCLUSIONS: DAH(30) has construct validity and is a readily obtainable generic patient-centred outcome measure. It is a pragmatic outcome measure for perioperative clinical trials.