Predicting cognitive sequelae in survivors of critical illness with cognitive screening tests

Abstract

Rationale: Survivors of critical illness have a high rate of cognitive impairments that may persist years after hospital discharge. Data are lacking regarding whether cognitive screening tests administered at hospital discharge can be used to predict which critically ill patients are likely to have long-term cognitive sequelae.

Objectives: This prospective study assessed whether two cognitive screening tests, the Mini-Mental State Examination (MMSE) and Mini-Cog, administered at hospital discharge, predict cognitive sequelae in survivors of critical illness 6 months after hospital discharge.

Methods: Seventy critically ill patients completed the MMSE and Mini-Cog just before hospital discharge. Of these 70 patients, 53 completed a neuropsychological battery 6 months after hospital discharge.

Measurements and main results: At hospital discharge, 45 patients (64%) had impaired performance on the MMSE (score < 27, mean = 24.4) and 32 (45%) on the Mini-Cog. Twenty-seven patients (39%) were impaired on both the MMSE and Mini-Cog, whereas only 20 patients (28%) had scores in the normal range on both tests. Cognitive sequelae occurred in 57% of survivors (30 of 53) at 6 months, with predominant dysfunction in the memory (38%) and executive (36%) domains. Logistic regression analyses showed that neither the MMSE nor the Mini-Cog predicted cognitive sequelae at 6 months.

Conclusions: A large number of critically ill survivors had cognitive impairments, as assessed by the MMSE and Mini-Cog, at hospital discharge. However, the MMSE and Mini-Cog scores did not predict long-term cognitive sequelae at 6-month follow-up and cannot be used as surrogate endpoints for long-term cognitive impairment.