The Successful Aging after Elective Surgery (SAGES) Study: Cohort Description and Data Quality Procedures

Abstract

Background/objectives: Delirium is the most common complication of major elective surgery in older patients. The Successful Aging after Elective Surgery (SAGES) study was designed to examine novel risk factors and long-term outcomes associated with delirium. This report describes the cohort, quality assurance procedures, and results.

Design: Long-term prospective cohort study.

Setting: Three academic medical centers.

Participants: A total of 566 patients age 70 and older without recognized dementia scheduled for elective major surgery.

Measurements: Participants were assessed preoperatively, daily during hospitalization, and at variable monthly intervals for up to 36 months post-discharge. Delirium was assessed in hospital by trained study staff. Study outcomes included cognitive and physical function. Novel risk factors for delirium were assessed including genetic and plasma biomarkers, neuroimaging markers, and cognitive reserve markers. Interrater reliability (kappa and weighted kappa) was assessed for key variables in 119 of the patient interviews.

Results: Participants were an average of 77 years old and 58% were female. The majority of patients (81%) were undergoing orthopedic surgery and 24% developed delirium post-operatively. Over 95% of eligible patients were followed for 18 months. There was >99% capture of key study outcomes (cognitive and functional status) at every study interview and interrater reliability was high (weighted kappas for delirium = 0.92 and for overall cognitive and functional outcomes = 0.94 -1.0). Completion rates for plasma biomarkers (4 timepoints) were 95%-99% and for neuroimaging (one year follow-up) was 86%.

Conclusion: The SAGES study will contribute to the understanding of novel risk factors, pathophysiology and long-term outcomes of delirium. This manuscript describes the cohort and data quality procedures, and will serve as a reference source for future studies based on SAGES.

Keywords: Data Quality; Delirium; Longitudinal Study; Surgical Outcome.

Figure 1. Summary of SAGES Enrollment

Eligible participants were age 70 years and older, English speaking, scheduled to undergo elective surgery with an anticipated length of stay of at least 3 days. Exclusion criteria included evidence of dementia, delirium, hospitalization within 3 months, terminal condition, legal blindness, severe deafness, history of schizophrenia or psychosis, and history of alcohol abuse. Patients who would be out of the catchment area at time of follow-up were also excluded from enrollment.