Transient Cognitive Impairment After Acute Stroke Has Little Long-Term Impact

Transient cognitive impairment during the acute phase of stroke is not associated with long-term outcome risk, according to study findings published in the journal BMC Neurology.

A common compilation of stroke is cognitive impairment, which can increase risk for institutionalization, disability, and mortality. However, transient cognitive impairment, which resolves during hospitalization, has not been sufficiently evaluated for its long-term implications.

This analysis was part of the PRospective Observational POLIsh Study (PROPOLIS) on post-stroke delirium conducted at Jagiellonian University Medical College in Poland. Adults (N=447) admitted within 48 hours of acute stroke or transient ischemic attack symptoms were evaluated for cognitive impairment using 2 Montreal Cognitive Assessment (MoCA) assessments at days 1-3 and 4-7. The outcomes of interest were discharge location, functional status, cognitive impairment, and mortality at 3 and 12 months. Transient cognitive impairment was defined by a decrease in MoCA scores by >2 points at the second assessment compared with the first.

The patients had the following characteristics:

• mean age, 69 (Interquartile range [IQR], 61-79);
• 51.45% were men;
• body mass index (BMI) was 26.67 (IQR, 23.88-29.74) kg/m²;
• duration of education was 11 (IQR, 10-13) years;
• 17.23% experienced delirium;
• 51.62% had another Trial of ORG 10172 in Acute Stroke Treatment (TOAST) etiology classification; and
• 46.53% had right hemisphere stroke.

Transient cognitive impairment was observed among 52.35% of patients; 30.20% were cognitively stable and 17.45% were cognitively impaired.

Compared with those in the cognitively stable group, predictors for transient cognitive impairment included in-hospital delirium (odds ratio [OR], 2.655; 95% CI, 1.284-5.494; P =.009), age (OR, 1.019; 95% CI, 1.003-1.036; P =.019), and education (OR, 0.928; 95% CI, 0.868-0.991; P =.026).

At 3 months, 23 patients had died and 21 were lost to follow-up, and at 12 months, 23 had died and 31 were lost to follow-up.

Transient cognitive impairment was associated with similar outcomes at 3 months compared with patients who were cognitively stable. Compared with those in the cognitively impaired cohort, patients with transient cognitive impairment were at lower risk for discharge to hospital or nursing home (adjusted OR [aOR], 0.410; 95% CI, 0.223-0.753; P =.004).

At the 12-month follow-up, no significant group differences were observed.

In a post-hoc analysis that excluded cases with delirium, transient cognitive impairment remained related with decreased risk for discharge to hospital or nursing home compared with the cognitively impaired group (OR, 0.473; P =.039).

In a second post-hoc analysis that stratified patients based on the first MoCA score, patients with transient cognitive impairment who had MoCA score >24 points were at lower risk for poor outcomes at 3 months compared with patients who were cognitively impaired (OR, 0.279; P =.041). Patients with MoCA <24 points were at lower risk for poor outcomes compared with patients who were cognitively stable (OR, 0.151; P =.012).

The major limitation of this study was that approximately 40% of the eligible patients were excluded primarily due to missing MoCA data.

Researchers concluded, “[T]ransient CI [cognitive impairment], which often occurs in the acute phase of stroke, does not increase the risk of long-term complications, regardless of the level of cognitive functioning in the acute stage of stroke. Differentiation between transient CI, delirium and permanent cognitive deficits seems important in clinical practice for proper assessment of long-term prognosis.”