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

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. ConclusionsThe IQCODE may be a suitable tool for assessing preoperative cognitive function and predicting postoperative delirium in elderly patients.