Usefulness of the Informant Questionnaire on Cognitive Decline in the Elderly for Predicting Postoperative Delirium in Elderly Patients: A Pilot Study

ABSTRACT

BACKGROUND AND PURPOSE: Preexisting cognitive impairment is the strongest risk factor for delirium. We performed a pilot study to investigate whether the Informant Questionnaire on Cognitive Decline in the Elderly (IQCODE), which is a good complement to direct cognitive testing, could be useful for predicting postoperative delirium in elderly patients. METHODS: Between June 2013 and May 2014, 37 patients aged 70 years or older underwent the Korean version of the Mini-Mental State Examination (K-MMSE) and completed the IQCODE (IQCODE-K) before elective spine surgery in the Spine Center at the Seoul National University Bundang Hospital. Delirium was assessed daily from the day after surgery until discharge. A Mann-Whitney U test was used to compare the K-MMSE scores and the IQCODE-K scores between the groups with and without postoperative delirium. RESULTS: A total of three of 37 (8.1%) patients developed delirium during their hospital stay. The K-MMSE scores were not different between the two groups (p=0.105), whereas the IQCODE-K scores of patients with delirium were significantly higher than those of patients without delirium (p=0.021), indicating greater cognitive and functional decline over the previous 10 years. CONCLUSION: The IQCODE may be a suitable tool for assessing preoperative cognitive function and predicting postoperative delirium in elderly patients.