Effect of Delirium and Other Major Complications on Outcomes After Elective Surgery in Older Adults.
OBJECTIVE
Major postoperative complications and delirium contribute independently to adverse outcomes and high resource use in patients who undergo major surgery; however, their interrelationship is not well examined.


OBJECTIVE
To evaluate the association of major postoperative complications and delirium, alone and combined, with adverse outcomes after surgery.


METHODS
Prospective cohort study in 2 large academic medical centers of 566 patients who were 70 years or older without recognized dementia or a history of delirium and underwent elective major orthopedic, vascular, or abdominal surgical procedures with a minimum 3-day hospitalization between June 18, 2010, and August 8, 2013. Data analysis took place from December 13, 2013, through May 1, 2015.


METHODS
Major postoperative complications, defined as life-altering or life-threatening events (Accordion Severity grade 2 or higher), were identified by expert-panel adjudication. Delirium was measured daily with the Confusion Assessment Method and a validated medical record review method. The following 4 subgroups were analyzed: (1) no complications or delirium; (2) complications only; (3) delirium only; and (4) complications and delirium. Adverse outcomes included a length of stay (LOS) of more than 5 days, institutional discharge, and rehospitalization within 30 days of discharge.


RESULTS
In the 566 participants, the mean (SD) age was 76.7 (5.2) years, 236 (41.7%) were male, and 523 (92.4%) were white. Forty-seven patients (8.3%) developed major complications and 135 (23.9%) developed delirium. Compared with no complications or delirium as the reference group, major complications only contributed to prolonged LOS only (relative risk [RR], 2.8; 95% CI, 1.9-4.0); by contrast, delirium only significantly increased all adverse outcomes, including prolonged LOS (RR, 1.9; 95% CI, 1.4-2.7), institutional discharge (RR, 1.5; 95% CI, 1.3-1.7), and 30-day readmission (RR, 2.3; 95% CI, 1.4-3.7). The subgroup with complications and delirium had the highest rates of all adverse outcomes, including prolonged LOS (RR, 3.4; 95% CI, 2.3-4.8), institutional discharge (RR, 1.8; 95% CI, 1.4-2.5), and 30-day readmission (RR, 3.0; 95% CI, 1.3-6.8). Delirium exerted the highest attributable risk at the population level (5.8%; 95% CI, 4.7-6.8) compared with all other adverse events (prolonged LOS, institutional discharge, or readmission).


CONCLUSIONS
Major postoperative complications and delirium are separately associated with adverse events and demonstrate a combined effect. Delirium occurs more frequently and has a greater effect at the population level than other major complications.
Department of Medicine, Beth Israel Deaconess Medical Center, Harvard Medical School, Boston, Massachusetts2Aging Brain Center, Institute for Aging Research, Hebrew SeniorLife, Boston, Massachusetts.
Lauren J
LJ
Gleason
Aging Brain Center, Institute for Aging Research, Hebrew SeniorLife, Boston, Massachusetts.
Eva M
EM
Schmitt
Aging Brain Center, Institute for Aging Research, Hebrew SeniorLife, Boston, Massachusetts.
Cyrus M
CM
Kosar
William F. Connell School of Nursing, Boston College, Boston, Massachusetts.
Patricia
P
Tabloski
Division of Geriatric Medicine and Meyers Primary Care Institute, University of Massachusetts Medical School, Worcester.
Jane S
JS
Saczynski
Department of Surgery, University of Colorado, Boulder.
Thomas
T
Robinson
Department of Surgery, Brigham and Women's Hospital, Harvard Medical School, Boston, Massachusetts.
Zara
Z
Cooper
Department of Surgery, University of Texas Medical Branch at Galveston, Galveston.
Selwyn O
SO
Rogers
Department of Psychiatry and Human Behavior, Warren Alpert Medical School, Brown University, Providence, Rhode Island.
Richard N
RN
Jones
Department of Medicine, Beth Israel Deaconess Medical Center, Harvard Medical School, Boston, Massachusetts.
Edward R
ER
Marcantonio
Department of Medicine, Beth Israel Deaconess Medical Center, Harvard Medical School, Boston, Massachusetts2Aging Brain Center, Institute for Aging Research, Hebrew SeniorLife, Boston, Massachusetts.
Sharon K
SK
Inouye
D000368:Aged; D003693:Delirium / Q000453:epidemiology* / Q000209:etiology; D017558:Elective Surgical Procedures / Q000009:adverse effects*; D005260:Female; D005500:Follow-Up Studies; D006801:Humans; D015994:Incidence; D008297:Male; D011183:Postoperative Complications / Q000453:epidemiology*; D011379:Prognosis; D011446:Prospective Studies; D018570:Risk Assessment / Q000379:methods*; D012307:Risk Factors; D014481:United States / Q000453:epidemiology