Systematic review and meta-analysis of the prevalence of cognitive impairment no dementia in the first year post-stroke

Introduction Increasing attention is being paid to interventions for cognitive impairment (CI) post-stroke, including for CI that does not meet dementia criteria. The aim of this paper was to conduct a systematic review and meta-analysis of the prevalence of cognitive impairment no dementia (CIND) within one year post-stroke. Patients and methods Pubmed, EMBASE and PsychInfo were searched for papers published in English in 1995–2017. Included studies were population or hospital-based cohort studies for first-ever/recurrent stroke, assessing CIND using standardised criteria at 1–12 months post-stroke. Abstracts were screened, followed by full text review of potentially relevant articles. Data were extracted using a standard form, and study quality was appraised using the Crowe Critical Appraisal Tool. A pooled prevalence of CIND with 95% confidence intervals (CI) was estimated using random-effects meta-analysis. Heterogeneity was measured using the I2 statistic. Results A total of 7000 abstracts were screened, followed by 1028 full text articles. Twenty-three articles were included in the systematic review, and 21 in the meta-analysis. The pooled CIND prevalence was 38% [95% CI = 32–43%] (I2=92.5%, p < 0.01). Study quality emerged as one source of heterogeneity. The five studies with the highest quality scores had no heterogeneity (I2=0%, p = 0.99), with a similar pooled prevalence (39%, 95%CI = 35–42%). Other sources of heterogeneity were stroke type, inclusion of pre-stroke CI, and age at assessment time. Discussion and conclusion: Meta-analysis of available studies indicates that in the first year post-stroke, 4 in 10 patients display a level of cognitive impairment that does not meet the criteria for dementia.