Determining the role of statins in Parkinson's disease risk reduction and disease modification: A comprehensive meta-analysis of 4 million participants' data.

BACKGROUND: Many observational studies have examined the association between statins and the incidence of Parkinson's disease (PD) in high-risk populations. On the other hand, clinical trials as well as other observational studies investigated the safety and efficacy of statins in slowing disease progression in PD patients. However, the evidence has been inconclusive in both questions. To that end, we conducted this systematic review and meta-analysis to synthesize evidence on the role of statins in decreasing the risk of PD among high-risk populations and as a possible disease-modifying agent for patients with PD. METHODS: A comprehensive literature search of electronic databases including PubMed, Scopus, Cochrane, and Web of Science has been performed. Relevant studies were chosen and data were extracted and analyzed using RevMan software version 5.4.1. RESULTS: Twenty-five studies (14 cohort, 9 case-control, and 2 randomized controlled trials) have been included in the present systematic review. Of them, 21 studies reported the association between statins and PD risk. Statins were found to significantly reduce the risk of developing PD (pooled RR 0.86, 95% CI [0.77-0.95], p < 0.005). Four studies investigated statins as a disease-modifying agent. The pooled mean difference (MD) in the UPDRS-III from baseline to endpoint did not differ significantly between the statin and control groups (MD -1.34 points, 95% CI [-3.81 to 1.14], p = 0.29). CONCLUSION: Although epidemiological observational studies showed that statin use was associated with a reduced risk of PD, current evidence is insufficient to support the role of statins in slowing the progression of PD. These findings are limited by the fact that most of the included studies are observational studies which carry a high risk of confounding bias which highlights the need for future well-designed RCTs.

Efficacy of intermittent theta burst stimulation (iTBS) on post-stroke cognitive impairment (PSCI): a systematic review and meta-analysis.

BACKGROUND: Stroke is a significant global cause of mortality and morbidity, and post-stroke cognitive impairment (PSCI) affects up to half of stroke patients. Despite the availability of pharmacological and non-pharmacological interventions, there is a lack of definitive effective treatments for PSCI. Non-invasive brain stimulation, particularly intermittent theta burst stimulation (iTBS), has emerged as a promising therapy for the treatment of PSCI. OBJECTIVE: This systematic review and meta-analysis aimed to evaluate the efficacy and safety of iTBS in enhancing cognitive function among patients with PSCI. METHODS: A comprehensive search was conducted across multiple databases, including PubMed, Web of Science, Scopus, Cochrane Library, and CNKI, to identify relevant randomized controlled trials published before April 2023. The primary outcome measured changes in global cognitive scales, while the secondary outcomes focused on improvements in attention, orientation, visual-spatial perception, and activities of daily living. RESULTS: The meta-analysis encompassed six studies involving 325 patients. The results demonstrated that iTBS led to a significant improvement in global cognitive scales (SMD = 1.12, 95% CI = [0.59 to 1.65], P < 0.0001), attention (SMD = 0.48, 95% CI [0.13 to 0.82], P = 0.007), visual perception (SMD = 0.99, 95% CI [0.13 to 1.86], P = 0.02), and activities of daily living (SMD = 0.82, 95% CI [0.55 to 1.08], P < 0.00001). However, there was no significant effect on orientation (SMD = 0.36, 95% CI [- 0.04 to 0.76], P = 0.07). Subgroup analysis based on the number of sessions was conducted, revealing a significant improvement in global cognition among patients with PSCI across the three categories (10 sessions, 20 sessions, and 30 sessions) with no between-group difference (P = 0.28). None of the included studies reported any serious adverse effects. CONCLUSION: In conclusion, iTBS appears to be a safe and effective non-invasive treatment that can enhance the cognitive abilities and daily living skills of patients with post-stroke cognitive impairment. However, our conclusion is constrained by the limited number of studies. Further high-quality, large-sample RCTs with extended follow-up periods are necessary to validate these findings. Integrating iTBS with brain imaging techniques, such as functional near-infrared spectroscopy and functional magnetic resonance, could aid in understanding the mechanism of iTBS action.