Association Between Obesity, Age, and Functional Decline in Survivors of Cardiac Surgery

Little is known about the effect of obesity on functional decline after cardiac surgery, especially in elderly adults. Our goal was to determine the association between obesity and functional decline in the 2 years after cardiac surgery and the interaction between obesity and age.

Retrospective cohort study.

The Health and Retirement Study, 2004-2014.

U.S. adults aged 50 and older who indicated having cardiac surgery and had a body mass index (BMI) of 18.5 kg/m² or greater (N = 1,731).

BMI was classified as normal or overweight (18.5-29.9 kg/m² ) and obese (≥30 kg/m² ). Primary outcome was decline in ability to perform an activity of daily living (ADL) after surgery.

Respondents had a median age of 71, 59.3% were female, and 34.3% were obese. Obese respondents had a higher incidence of ADL decline (22.4%) than those who were not obese (17.1%) (P = .007). In the multivariable analysis of our full cohort, obesity was not associated with ADL decline (odds ratio (OR)=1.20, 95% confidence interval (CI)=0.90-1.59, P = .21) after cardiac surgery, although obese respondents aged 50 to 79 had greater odds of ADL decline (OR=1.45, 95% CI=1.06-2.00, P = .02). Obese respondents aged 80 and older had nonstatistically significantly lower odds of ADL decline (OR=0.61, 95% CI=0.30-1.24, P = .18) compared to non-obese respondents.

The association between obesity and postoperative functional decline in survivors of cardiac surgery differed according to age. Additional research is needed to identify interventions to improve outcomes in groups of older adults in whom obesity may increase the risk of postoperative functional decline.