Decreased preoperative functional status is associated with increased mortality following coronary artery bypass graft surgery

OBJECTIVES: Functional status prior to coronary artery bypass graft surgery may be a risk factor for post-operative adverse events. We sought to examine the association between functional status in the 3 months prior to coronary artery bypass graft surgery and subsequent 180 day mortality. DESIGN, SETTING, AND PARTICIPANTS: We performed a single center retrospective cohort study in 718 adults who received coronary artery bypass graft surgery from 2002 to 2014. EXPOSURES: The exposure of interest was functional status determined within the 3 months preceding coronary artery bypass graft surgery. Functional status was measured and rated by a licensed physical therapist based on qualitative categories adapted from the Functional Independence Measure. MAIN OUTCOMES AND MEASURES: The main outcome was 180-day all-cause mortality. A categorical risk prediction score was derived based on a logistic regression model of the function grades for each assessment. RESULTS: In a logistic regression model adjusted for age, gender, New York Heart Association Class III/IV, chronic lung disease, hypertension, diabetes, cerebrovascular disease, and the Society of Thoracic Surgeons score, the lowest quartile of functional status was associated with an increased odds of 180-day mortality compared to patients with highest quartile of functional status [OR = 4.45 (95%CI 1.35, 14.69; P = 0.014)]. CONCLUSIONS: Lower functional status prior to coronary artery bypass graft surgery is associated with increased 180-day all-cause mortality.