Impact of Pre-Stroke Dementia or Mild Cognitive Impairment on Stroke Outcome: A Systematic Review and Meta-Analysis

Background and Objective: Pre-stroke dementia (PSD) and pre-stroke mild cognitive impairment (PSMCI) are important risk factors for stroke. The present meta-analysis aimed to investigate the impact of PSD or PSMCI on stroke outcomes. Methods: Electronic databases (PubMed, EMbase, Google Scholar, Cochrane Library, and TRIP) were screened for eligible studies published prior to March 31, 2021. Risk ratios (RR) and mean differences with 95% confidence intervals (CIs) using random or fixed effect models were used to calculate pooled estimates. Study quality was assessed using the Newcastle Ottawa Scale. Results: Fifteen studies were included in our meta-analysis. Pooled data from ten studies involving 3,107 PSD and 20,645 non-PSD subjects showed a higher risk of mortality in PSD patients (RR = 2.03; 95% CI: 1.40–2.91; I2 = 89%). Risk of recurrent stroke risk was observed more in patients with PSD compared to non-PSD patients (RR = 2.02; 95% CI: 1.40–2.91; I2 = 0%). Three studies involving 300 mild cognitive impairment (MCI) and 1,025 normal cognition subjects showed a significant increased risk of mortality in stroke patients with MCI (RR = 2.43; 95% CI: 1.81–3.27; I2 = 20%). However, elevated stroke severity was not observed in PSMCI patients. Conclusions: Our meta-analysis shows an increased risk of mortality in stroke patients with a history of PSD and PSMCI. Proper clinical management and increased attention are therefore required for the prevention and management of stroke in patients with cognitive deficits.