Abstract
The efficacy of stem cell therapy for ischemic stroke in terms of functional outcomes remains unclear. We conducted a systematic review and meta-analysis of randomized controlled trials (PROSPERO: CRD42024503763) to assess the efficacy and safety of stem cell therapy for acute/subacute ischemic stroke, focusing on long-term outcomes. Studies of patients undergoing stem cell transplantation within 1 month of stroke onset were included. We searched five databases for publications up to January 17, 2024. Summary data were extracted from published reports. The primary outcome was the modified Rankin Scale (mRS) score. Measures of effect were risk ratios (RRs) with 95% confidence intervals (CIs). A random-effects model was used when I(2) was > 25%; otherwise, a fixed-effects model was used. Common serious adverse events were epilepsy, gastrointestinal disorders, and cardiac disorders. The risk of bias was assessed using the Cochrane Risk of Bias tool version 2. In total, 13 trials involving 872 (519 men) patients were included. The 1-year incidence of mRS scores 0-1 was higher in the cell-therapy group (45/195) than that in the control group (23/179; RR = 1.74 [95% CI = 1.09-2.77]; p = 0.020; I(2) = 0%). The 90-day incidence of mRS scores 0-2 was also higher (RR = 1.31 [95% CI = 1.01-1.70]; p = 0.044; I(2) = 0%). No significant differences were observed in serious adverse events or mortality. Stem cell therapy for acute/subacute ischemic stroke within 1 month of onset is safe and significantly improves long-term functional outcomes, although the mechanisms of action need to be elucidated and treatment protocols standardized to establish stem cell therapy as a standard care option for ischemic stroke.