Interrelationship of postoperative delirium and cognitive impairment and their impact on the functional status in older patients undergoing orthopaedic surgery: a prospective cohort study

Chih-Kuang Liang; Chin-Liang Chu; Ming-Yueh Chou; Yu-Te Lin; Ti Lu; Chien-Jen Hsu; Liang-Kung Chen

doi:10.1371/journal.pone.0110339

Interrelationship of postoperative delirium and cognitive impairment and their impact on the functional status in older patients undergoing orthopaedic surgery: a prospective cohort study

PLoS One. 2014 Nov 17;9(11):e110339. doi: 10.1371/journal.pone.0110339. eCollection 2014.

Authors

Chih-Kuang Liang¹, Chin-Liang Chu², Ming-Yueh Chou³, Yu-Te Lin¹, Ti Lu⁴, Chien-Jen Hsu⁵, Liang-Kung Chen⁶

Affiliations

¹ Center for Geriatrics and Gerontology, Kaohsiung Veterans General Hospital, Kaohsiung, Taiwan; Division of Neurology, Department of Medicine, Kaohsiung Veterans General Hospital Kaohsiung, Taiwan; Aging and Health Research Center, National Yang Ming University, Taipei, Taiwan.
² Center for Geriatrics and Gerontology, Kaohsiung Veterans General Hospital, Kaohsiung, Taiwan; Aging and Health Research Center, National Yang Ming University, Taipei, Taiwan; Department of Psychiatry, Kaohsiung Veterans General Hospital, Kaohsiung, Taiwan.
³ Center for Geriatrics and Gerontology, Kaohsiung Veterans General Hospital, Kaohsiung, Taiwan; Aging and Health Research Center, National Yang Ming University, Taipei, Taiwan; Department of Family Medicine, Kaohsiung Veterans General Hospital, Kaohsiung, Taiwan.
⁴ Department of Psychiatry, Kaohsiung Veterans General Hospital, Kaohsiung, Taiwan.
⁵ Department of Orthopaedics, Kaohsiung Veterans General Hospital, Kaohsiung, Taiwan.
⁶ Aging and Health Research Center, National Yang Ming University, Taipei, Taiwan; Center for Geriatrics and Gerontology, Taipei Veterans General Hospital, Taipei, Taiwan.

Abstract

Background: The impact of postoperative delirium on post-discharge functional status of older patients remains unclear, and little is known regarding the interrelationship between cognitive impairment and post-operative delirium. Therefore, the main purpose was to evaluate the post-discharge functional status of patients who experience delirium after undergoing orthopaedic surgery and the interrelationship of postoperative delirium with underlying cognitive impairment.

Method: This prospective cohort study, conducted at a tertiary care medical center from April 2011 to March 2012, enrolled all subjects aged over 60 years who were admitted for orthopaedic surgery. The baseline characteristics (age, gender, BMI, and living arrangement), surgery-related factors (ASA class, admission type, type of surgery, and length of hospital stay), results of geriatric assessment (postoperative delirium, cognition, depressive mood, comorbidity, pain, malnutrition, polypharmacy, ADL, and instrumental [I]ADL) and 1-12-month postoperative ADL and IADL functional status were collected for analysis.

Results: Overall, 9.1% of 232 patients (mean age: 74.7 ± 7.8 years) experienced postoperative delirium, which was significantly associated with IADL decline at only 6 and 12 months postoperatively (RR: 6.22, 95% CI: 1.08-35.70 and RR: 12.54, 95% CI: 1.88-83.71, respectively). Delirium superimposed on cognitive impairment was a significant predictor for poor functional status at 6 and 12 months postoperatively (RR: 12.80, 95% CI: 1.65-99.40 for ADL at the 6th month, and RR: 7.96, 95% CI: 1.35-46.99 at the 12th month; RR: 13.68, 95% CI: 1.94-96.55 for IADL at the 6th month, and RR: 30.61, 95% CI: 2.94-318.54 at the 12th month, respectively).

Conclusion: Postoperative delirium is predictive of IADL decline in older patients undergoing orthopaedic surgery, and delirium superimposed on cognitive impairment is an independent risk factor for deterioration of ADL and IADL functional status. Early identification of cognitive function and to prevent delirium are needed to improve functional status following orthopaedic surgery.

Publication types

Research Support, U.S. Gov't, Non-P.H.S.

MeSH terms

Aged
Aged, 80 and over
Cognition Disorders / epidemiology
Cognition Disorders / etiology*
Delirium / epidemiology
Delirium / etiology*
Female
Follow-Up Studies
Geriatric Assessment*
Humans
Male
Orthopedic Procedures / adverse effects*
Population Surveillance
Postoperative Complications*
Prospective Studies
Risk Factors
Taiwan / epidemiology
Time Factors

Grants and funding

This work was supported by grants from the Veteran Affairs Commission of Taiwan. The funders had no role in study design, data collection and analysis, decision to publish, or preparation of the manuscript.