The association between skeletal muscle mass and blood pressure in the adult population: A systematic review

Problem

Cardiovascular disease (CVD) is the leading cause of premature mortality worldwide. Hypertension is a major risk factor for developing CVD. Early identification of CVD risk factors is essential to improve health outcomes. Skeletal muscle mass (SMM) is a promising predictor of CVD outcomes. There is conflicting evidence about the strength and the direction of the association between SMM and blood pressure (BP). Therefore, this review aims to assess the association between SMM and BP in adults

Approach

This systematic review undertook a multi-database search of MEDLINE, PubMed, and Embase from the date of inception until the 19th of July 2023. It included observational and interventional studies which assessed the association between SMM (using clinically validated methods) and BP in adults with or without hypertension in any clinical setting. Muscular dystrophies and secondary sarcopenia studies were excluded. Full paper screening, data extraction and assessment of quality were independently undertaken by two reviewers. Due to the heterogeneity of included studies a vote counting, and narrative synthesis method were employed. Before commencing, this systematic review was registered on PROSPERO (project ID: CRD42023485314).

Findings

“After duplicate removal, 3,091 studies were identified of which 12 studies were included. Out of the eight studies which reported an association between sarcopenia and BP; two found a positive association with hypertension, one found a positive association with systolic BP variability, one found a positive association with orthostatic hypotension, one found no association with hypertension, two found a negative association with hypertension and one found a negative association with systolic BP. Out of the four studies which measured the association between SMM and BP (one study assessed both systolic and diastolic BP); one reported a negative association with hypertension, one reported a positive association with hypertension, one found a negative association with systolic BP and two found a positive association with diastolic BP.In conclusion, there are no established reference values for SMM. The studies used different methods to measure and report their findings. It was also unclear whether all moderating factors have been considered, making it difficult to establish a consistent association”.

Consequences

The exact relationship between SMM and BP remains unclear. Few theories suggest that low SMM can cause insulin resistance and high arterial stiffness which contributes to raised BP (negative association). Others suggest that increased SMM causes left ventricular hypertrophy and activates the sympathetic nervous system, leading to elevated BP (positive association). Further research is needed to determine whether there is a link between SMM and BP, considering the wide variety of confounding factors that could influence the strength or direction of this relationship. Additionally, there is a need to establish benchmark SMM values and to validate these values across different adult populations based on age, gender and ethnicity.