Impact of perioperative inflammation on days alive and at home after surgery.

Background: Perioperative inflammation is associated with perioperative complications, including delirium, that are associated with a reduced number of postoperative days alive and at home at 90 days (DAH90). We tested whether inflammation was associated with DAH90 even when adjusting for perioperative factors, and whether inflammation independently was associated with DAH90 when adjusting for delirium. Methods: We conducted a prospective cohort study of major, non-intracranial surgical patients who were older than 65 yr (n=134). We measured postoperative delirium incidence and severity, and changes in interleukin (IL)-8 and IL-10 in blood plasma. Our primary outcome, DAH90, was analysed using quantile regression. Results: Before adjusting for delirium, a postoperative day 1 increased IL-8 was associated with fewer DAH90 at the 0.75 quantile (ß=-0.082; 95% confidence interval [CI], -0.19 to -0.006) after adjusting for demographic (age and sex) and perioperative factors (cardiovascular surgery, National Surgical Quality Improvement Program risk of death, and operative time). IL-10 was similarly associated with DAH90 at the 0.5 (ß=-0.026; 95% CI, -0.19 to -0.001) and 0.75 (ß= -0.035; 95% CI, -0.07 to -0.006) quantiles. Neither cytokine was significantly associated with DAH90 once delirium and baseline Trail Making Test B were added to the models. Conclusions: Perioperative inflammation predicts DAH90, but when delirium is added to the model inflammation loses significance as a predictor, whereas delirium is significant. Targeting perioperative inflammation may reduce delirium and moderate hospital readmission and mortality. Clinical trial registration: NCT03124303.