Evolution of cognitive impairment after stroke and risk factors for delayed progression

Cognitive decline occurs in approximately 30% of stroke patients. Acute risk factors have been identified, but long-term risk has not been examined in large samples. The purpose of this research was to determine factors associated with the progression of cognitive impairment after stroke.

Consecutive stroke patients (193) without previous dementia were assessed 3 months after stroke with an extensive neuropsychological battery and diagnosed according to the Diagnostic and Statistical Manual of Mental Disorders Fourth Edition criteria and the Clinical Dementia Rating as normal (139), cognitive decline without dementia (18), or dementia (18 mild, 10 moderate, and 8 severe). After a 24-month follow-up, they were classified as stable, progressing, or improving, according to change in Clinical Dementia Rating score. The determinants of progression of cognitive decline were ascertained by logistic regression analysis of all clinical, neuroimaging, and complementary data.

Cognitive status at 24 months was stable in most cases (151; 78.2%), decline progressed in 27 (14%; 6 demented and 21 nondemented), and improved in 15 (7.8%; 7 demented and 8 nondemented). Seven nondemented patients became demented at 24 months, and 5 demented became nondemented. The age (odds ratio [OR], 1.05; 95% CI, 1.01 to 1.1), mental decline before stroke (OR, 1.14; 95% CI, 1.02 to 1.27), number of prescribed drugs (OR, 1.34; 95% CI, 1.05 to 1.72), diastolic blood pressure on admission (OR, 0.96; 95% CI, 0.93 to 0.99), and episodes of hypotension during admission (OR, 7.61; 95% CI, 1.11 to 52.1) were significantly associated with cognitive deterioration.

Cognition is rather stable for 2 years after stroke. Both progression and improvement of cognitive impairment are frequent in demented patients. Age, previous cognitive decline, polypharmacy, and hypotension during admission are risk factors for progression.