Motoric cognitive risk syndrome as a predictor of adverse health outcomes: A systematic review and meta-analysis

Introduction: Motoric cognitive risk syndrome (MCR) is a newly proposed pre-dementia syndrome characterized by subjective cognitive complaints (SCC) and slow gait (SG). Increasing evidence links MCR to several adverse health outcomes, but the specific relationship between MCR and the risk of frailty, Alzheimer’s disease (AD) and vascular dementia (VaD) remains unclear. Additionally, literature lacks analysis of MCR’s components and associated health outcomes, complicating risk identification. This systematic review and meta-analysis aim to provide a comprehensive overview of MCR’s predictive value for adverse health outcomes. Methods: Relevant cross-sectional, cohort, and longitudinal studies examining the association between MCR and adverse health outcomes were extracted from seven electronic databases. The Newcastle Ottawa Scale (NOS) and modified NOS were used to assess the risk of bias in studies included in the analysis. Relative ratios (RRs) and 95% confidence intervals (CIs) were pooled for outcomes associated with MCR. Results: Twenty-eight longitudinal or cohort studies and four cross-sectional studies with 1,224,569 participants were included in the final analysis. The risk of bias in all included studies was rated as low or moderate. Pooled analysis of RR indicated that MCR had a greater probability of increased the risk of dementia (adjusted RR=2.02; 95%CI=1.94-2.11), cognitive impairment (adjusted RR=1.72; 95%CI=1.49-1.99), falls (adjusted RR=1.32; 95%CI=1.17-1.50), mortality (adjusted RR=1.66; 95%CI=1.32-2.10); MCR had more prominent predictive efficacy for AD (adjusted RR=2.23; 95%CI=1.81-2.76) compared to VaD (adjusted RR=3.78; 95%CI=0.49-28.95), while excluding analyses from the study that utilized the Timed-up-and-go test and one-leg-standing to evaluate gait speed. One study examined the association between MCR and disability (HR=1.69; 95%CI=1.08-2.02) and frailty (OR=5.53; 95%CI=1.46-20.89). SG was a stronger predictor of the risk for dementia and falls than SCC (adjusted RR=1.22; 95%CI=1.11-1.34 vs. adjusted RR=1.19; 95%CI= 1.03-1.38). Conclusion: MCR increases the risk of developing any discussed adverse health outcomes and the predictive value for AD is superior to VaD. Additionally, SG is a stronger predictor of dementia and falls than SCC. Therefore, MCR should be routinely assessed among adults to prevent poor prognosis, and provide evidence to support future targeted interventions.