Left ventricular hypertrophy in association with cognitive impairment: a systematic review and meta-analysis

Left ventricular hypertrophy (LVH) is a marker of prolonged exposure to high blood pressure and a predictor of cardiovascular disease risk. The objective of the current study was to investigate its association with cognitive function. Following standard guidelines, pairs of independent reviewers screened 2359 articles to search for studies that addressed the research question, extracted data and evaluated the quality of the studies using the Newcastle-Ottawa scale; authors were contacted for additional data. A random-effects meta-analysis and a meta-regression analysis were performed. Eighteen eligible studies using various methodologies and of varying quality were identified. However, both cross-sectional and prospective studies were indicative of a positive association between LVH and cognitive impairment or cognitive performance and decline in both population-based and patient-based subjects. The meta-analysis showed an increased risk of cognitive impairment among subjects with LVH in population-based studies (9 studies; 28 648 subjects; odds ratio (OR): 1.40, 95% confidence interval (CI): 1.18-1.66) and studies exclusively on hypertensive subjects (3 studies; 1262 subjects; OR: 2.14, 95% CI: 1.39-3.30). The effect was stronger when assessing LVH by echocardiography rather than electrocardiogram and was retained in the sensitivity analyses of prospective and highest quality studies and studies adjusting for hypertension or blood pressure levels. No heterogeneity or publication bias was documented, whereas the presence of hypertension seemed to reinforce the reported association, as derived from the meta-regression analysis. There is evidence suggesting an independent association of LVH with cognitive impairment. Because of the highly heterogeneous methodologies, future large prospective studies with clinically defined dementia outcomes are needed to replicate the findings.