Intensive BP Control May Raise Heart Risk in Those with Low Muscle Mass: Study
Researchers have discovered that tight blood pressure (BP) control can enhance cardiovascular risks in those with low muscle mass, but continues to provide protection to the brain. This was inferred from a new analysis of the Systolic Blood Pressure Intervention Trial (SPRINT), a groundbreaking study that sought to learn about how aggressive BP goals influence health outcomes. A recent study was conducted by Wei-Hua and fellow researchers which was published in the American Journal of Hypertension. Although tight BP control has been linked to cardiovascular and cerebral benefits in the general population, its safety profile in those with low muscle mass was not previously well understood.
The research assessed cardiovascular and cognitive outcomes in individuals with differing muscle mass. It made an important and somewhat surprising finding: for individuals with low muscle mass, very aggressive BP control might actually harm the heart. The cognitive effects of aggressive BP control were preserved, independent of muscle mass.
The authors analyzed data from 6,367 subjects who were included in the SPRINT trial. Muscle mass levels were assessed at baseline to determine those with low muscle mass, representing 7.4% of the overall sample (469 subjects). The major aim was to examine how muscle mass status affects the effects of intensive BP control, specifically cardiovascular events and cognitive impairment.
For this purpose, Cox proportional hazard models and generalized linear models were employed to compare relative and absolute risks. Landmark analyses with cutoffs at 3.4 and 2 years were used to determine the time-dependent effects of intensive BP lowering on outcomes.
Key Findings
Cardiovascular Outcomes:
• In subjects with normal muscle mass, intensive BP control lowered the absolute risk of primary cardiovascular events by 5.2 events per 1,000 person-years (Hazard Ratio [HR]: 0.71; 95% Confidence Interval [CI]: 0.58–0.89).
• Subjects with low muscle mass had an increase in cardiovascular events by 11.1 per 1,000 person-years (HR: 1.72; 95% CI: 0.89–3.34), suggesting potential harm (P for interaction = 0.013).
• The higher CV risk in the low muscle mass group became statistically significant with 3.4 years of intensive BP control (P = 0.043).
Cognitive Outcomes:
• Irrespective of muscle mass, intensive BP control lowered relative and absolute risks for cognitive decline, without significant interaction between muscle mass status and cognitive gains (all P values for interaction > 0.05).
The research determines that strict BP control enhances cardiovascular risk among individuals with low muscle mass, regardless of its beneficial impact on cognition. This information highlights the need for personalized hypertension treatment strategies, particularly in older or frail individuals whose muscle mass could be reduced.
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