Brain and Heart Interactions Delineating Cardiac Dysfunction in Four Common Neurological Disorders: A Systematic Review and Meta-analysis.

Neurological and cardiovascular disorders are the leading causes of morbidity and mortality worldwide. While the effects of cardiovascular disease (CD) on the nervous system are well understood, understanding of the reciprocal relationship has only recently become clearer. Based on disability-adjusted life years, this systematic review and meta-analysis present the pooled incidence and association of CD in 4 selected common, noncommunicable neurological disorders: (1) migraine, (2) Alzheimer disease and other dementias, (3) epilepsy, and (4) head injury. Sixty-five studies, including over 4 and a half million patients, were identified for inclusion in this review. Among the 4 neurological disorders, the majority of patients (89.4%) had epilepsy, 9.6% had migraine, and 0.97% had head injury. Alzheimer disease and other dementias were reported in only 0.02% of patients. The pooled effect estimates (incidence and association) of CD in the 4 neurological disorders was 10% (95% CI: 5.8%-16.9%; I2 = 99.94%). When stratified by the neurological disorder, head injury was associated with the highest incidence of CD (28%). The 4 neurological disorders were associated with a 2-fold increased odds for developing CD in comparison to patients without neurological disorders. Epilepsy was associated with the greatest increased odds of developing CD (odds ratio: 2.25; 95% CI: 1.82-2.79; P = 0.04). In studies that reported this variable, the pooled hazard ratio was 1.64 (95% CI: 1.38-1.94), with head injury having the highest hazard ratio (2.17; 95% CI: 1.30-3.61). Large prospective database studies are required to understand the long-term consequences of CD in patients with neurological disorders.