• heart failure
• frailty
• older people
• deiodination
• outcomes

ABSTRACT:
Frailty syndrome is common in older patients with HF, and both frailty and heart failure share common mechanistic features, including strong relations with a high burden of comorbidities, inflammation, and sarcopenia. To date, however, there is no universally accepted definition of frailty. Various models have been proposed to identify and measure it, including some based on clinical criteria and phenotypes, but a simple, accurate biomarker associated with this syndrome has been not yet established. The current PhD thesis discusses the use of the FT3/FT4 ratio in determining frailty in elderly patients with acute heart failure. The study found that patients with a FT3/FT4 ratio lower than 1.7 had a significantly higher mortality risk compared to patients with higher levels, after accounting for confounding factors. These patients were found to be frailer, more cognitively and functionally impaired, and more likely to have sarcopenia. The FT3/FT4 ratio was also found to be linked to nutritional and inflammatory biomarkers as well as strength and functional capability. The findings suggest that peripheral thyroxine deiodination could be used as a hallmark of healthy or unhealthy aging. The study recommends the use of FT3/FT4 as a potential biomarker in stratifying elderly comorbid patients who are at risk of poor outcomes in order to optimize their care and management.