Preoperative Alzheimer’s Disease and Related Dementias Influence Outcomes of Colorectal Surgery

In general, Alzheimer’s disease and related dementias (ADRD) result in poor outcomes for patients undergoing surgery: functional decline, postoperative delirium, and poor rehabilitation potential. However, it hadn’t been determined how cognitive impairment specifically affects recovery after colorectal surgery.

Joel S. Weissman, PhD, deputy director and chief scientific officer of the Center for Surgery and Public Health at Brigham and Women’s Hospital, Clancy J. Clark, MD, a surgical oncologist at Wake Forest Baptist Health, and colleagues have completed the first large, multicenter study of this issue that included both elective and emergent colorectal procedures.

In The American Journal of Surgery, they say patients with ADRD required longer postoperative hospital stays, were more likely to be readmitted, and were more likely to have postoperative complications than patients with normal cognitive function.


The study included 5,925 patients over age 65 with at least one inpatient colon or rectal surgery at Mass General Brigham or Wake Forest between January 1, 2007, and October 1, 2017. Patients with ADRD were identified using a validated algorithm developed at Mass General Brigham that considers diagnosis codes from all prior inpatient and outpatient encounters and the current hospitalization.

Characteristics of the Cohort

The cohort’s median age was 74, and 58% of patients were female. 285 (4.8%) had a diagnosis of ADRD.

Nearly all patients, 97%, had at least one comorbidity. Patients with ADRD were more likely to have multiple comorbidities, and the median Elixhauser comorbidity index was slightly but significantly higher for patients with ADRD than those without (14.0 vs. 11.2; P=0.008).

As shown in previous research on surgery in general, emergent colorectal operations were significantly more common for patients with ADRD (28% vs. 14% for those without; P<0.001).

Cancer and diverticulitis were the most common indications for surgery in both subgroups. However, prolapse, bleeding, vascular disease, and obstruction were more common among ADRD patients, probably explaining that group’s higher rate of emergent surgery.

Unadjusted Results

Several outcomes differed significantly between patients with ADRD and those without:

  • Mortality (primary outcome)—The 90-day mortality rate was 14% for patients with ADRD vs. 8% for those without (P=0.001); in-hospital and 30-day mortality rates were borderline significantly higher in patients with ADRD
  • Complications—61% of patients with ADRD had at least one in-hospital complication, compared with 48% without ADRD (P<0.001); 74% vs. 64% had a complication within 90 days after surgery (P<0.001)
  • Average length of hospital stay—7.1 days for patients with ADRD vs. 6.1 days for patients without (P=0.001)
  • Discharge to a facility—30% of patients with ADRD vs. 29% of those without (P<0.001)
  • Readmission—30-day readmission rate, 23% of patients with ADRD vs. 15% of those without (P<0.001); 90-day readmission rate, 29% vs. 23% (P=0.027)

Adjusted Results

In multivariable analyses adjusted for sex, age, Elixhauser comorbidity score, and emergency operation, ADRD was associated with:

  • Prolonged length of stay (>6 days)—OR, 1.50 (P=0.004)
  • Increased risk of postoperative complication—OR, 1.32 (P=0.049)
  • Increased risk of 30-day readmission—OR 1.57 (P=0.004)

In-hospital, 30-day, and 90-day mortality were similar for patients with and without ADRD.

Improved Preoperative Care Needed

Patients with ADRD need careful preoperative optimization that includes management of comorbidities, preoperative discussion of discharge destination, and education about the prospect of substantially longer hospitalization. Post-discharge telemedicine and in-home assessments may help prevent readmissions in this high-risk population.

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