Validity of the IQCODE-CA: An informant questionnaire on cognitive decline modified for a cardiac arrest population

Erik Blennow Nordström; Gisela Lilja; Kristofer Årestedt; Hans Friberg; Niklas Nielsen; Susanna Vestberg; Tobias Cronberg

doi:10.1016/j.resuscitation.2017.06.012

Validity of the IQCODE-CA: An informant questionnaire on cognitive decline modified for a cardiac arrest population

Resuscitation. 2017 Sep:118:8-14. doi: 10.1016/j.resuscitation.2017.06.012. Epub 2017 Jun 24.

Authors

Erik Blennow Nordström¹, Gisela Lilja², Kristofer Årestedt³, Hans Friberg⁴, Niklas Nielsen⁵, Susanna Vestberg⁶, Tobias Cronberg²

Affiliations

¹ Lund University, Skane University Hospital, Department of Clinical Sciences Lund, Neurology, Lund, Sweden. Electronic address: erik.blennow_nordstrom@med.lu.se.
² Lund University, Skane University Hospital, Department of Clinical Sciences Lund, Neurology, Lund, Sweden.
³ Linnaeus University, Faculty of Health and Life Sciences, Kalmar, Sweden; Kalmar County Hospital, Department of Research, Kalmar, Sweden.
⁴ Lund University, Skane University Hospital, Department of Clinical Sciences Lund, Intensive and Perioperative Care, Lund, Sweden.
⁵ Lund University, Helsingborg Hospital, Department of Clinical Sciences Lund, Anesthesiology and Intensive Care, Lund, Sweden.
⁶ Lund University, Faculty of Social Sciences, Department of Psychology, Lund, Sweden.

PMID: 28655624
DOI: 10.1016/j.resuscitation.2017.06.012

Abstract

Aim: To examine the psychometric properties of a modified version of the Informant Questionnaire on Cognitive Decline in the Elderly (IQCODE), for a cardiac arrest population (IQCODE-CA).

Methods: The IQCODE-CA, a 26-item observer-reported questionnaire, was completed by informants, defined as relatives or close friends, of 268 out-of-hospital cardiac arrest (OHCA) survivors who participated in the Target Temperature Management trial in a scheduled follow-up 180±14days after OHCA. Survivors completed the Mini Mental State Examination (MMSE), the Rivermead Behavioural Memory Test (RBMT) and the Hospital Anxiety and Depression Scale (HADS). An exploratory factor analysis was performed. Associations between IQCODE-CA results and demographic variables along with other instruments were calculated. Area under the curve (AUC) ratios were evaluated to examine discrimination.

Results: The IQCODE-CA measured one factor, global cognitive decline, with high internal consistency (ordinal α=0.95). Age, gender or education did not influence the IQCODE-CA score. Associations with performance-based measures of global cognitive function as well as anxiety and depression ranged from small to moderate (r_s=-0.29 to 0.38). AUC ratios ranged from fair to good (0.72-0.81). According to the MMSE and RBMT, the optimal cut-off score to identify cognitive decline on the IQCODE-CA was 3.04. Using this value, 53% of the survivors were under the cut-off.

Conclusions: The IQCODE-CA identified a large amount of survivors with possible cognitive problems, making it useful when screening for cognitive decline post-CA. Due to lower AUC ratios than desired, additional performance-based measures should be used to improve the overall screening methodology.

Keywords: Cardiac arrest; Cognitive screening; Outcome; Psychometrics; Reliability; Validity.

Publication types

Validation Study

MeSH terms

Aged
Anxiety / diagnosis
Cardiopulmonary Resuscitation / statistics & numerical data
Cognitive Dysfunction / diagnosis*
Depression / diagnosis
Factor Analysis, Statistical
Female
Health Surveys / standards*
Humans
Linear Models
Male
Mental Status and Dementia Tests*
Middle Aged
Out-of-Hospital Cardiac Arrest / complications*
Psychometrics