MET-PREVENT: metformin to improve physical performance in older people with sarcopenia and physical prefrailty/frailty - protocol for a double-blind, randomised controlled proof-of-concept trial

The Current Landscape of Pharmacotherapies for Sarcopenia

Sarcopenia is a skeletal muscle disorder characterized by progressive and generalized decline in muscle mass and function. Although it is mostly known as an age-related disorder, it can also occur secondary to systemic diseases such as malignancy or organ failure. It has demonstrated a significant relationship with adverse outcomes, e.g., falls, disabilities, and even mortality. Several breakthroughs have been made to find a pharmaceutical therapy for sarcopenia over the years, and some have come up with promising findings. Yet still no drug has been approved for its treatment. The key factor that makes finding an effective pharmacotherapy so challenging is the general paradigm of standalone/single diseases, traditionally adopted in medicine. Today, it is well known that sarcopenia is a complex disorder caused by multiple factors, e.g., imbalance in protein turnover, satellite cell and mitochondrial dysfunction, hormonal changes, low-grade inflammation, senescence, anorexia of aging, and behavioral factors such as low physical activity. Therefore, pharmaceuticals, either alone or combined, that exhibit multiple actions on these factors simultaneously will likely be the drug of choice to manage sarcopenia. Among various drug options explored throughout the years, testosterone still has the most cumulated evidence regarding its effects on muscle health and its safety. A mas receptor agonist, BIO101, stands out as a recent promising pharmaceutical. In addition to the conventional strategies (i.e., nutritional support and physical exercise), therapeutics with multiple targets of action or combination of multiple therapeutics with different targets/modes of action appear to promise greater benefit for the prevention and treatment of sarcopenia.

[Therapy of physical frailty]

As an overarching geriatric syndrome, frailty describes a potentially reversible transitional stage between functional autonomy and irreversible disability. Thus, frailty addresses a "window of opportunity" in which functional limitations can be successfully treated. This article provides an overview of the therapeutic approaches and their scientific evidence.

Repurposing Drugs for Diabetes Mellitus as Potential Pharmacological Treatments for Sarcopenia - A Narrative Review

Sarcopenia, the age-related loss of muscle strength and mass or quality, is a common condition with major adverse consequences. Although the pathophysiology is incompletely understood, there are common mechanisms between sarcopenia and the phenomenon of accelerated ageing seen in diabetes mellitus. Drugs currently used to treat type 2 diabetes mellitus may have mechanisms of action that are relevant to the prevention and treatment of sarcopenia, for those with type 2 diabetes and those without diabetes. This review summarises shared pathophysiology between sarcopenia and diabetes mellitus, including the effects of advanced glycation end products, mitochondrial dysfunction, chronic inflammation and changes to the insulin signalling pathway. Cellular and animal models have generated intriguing, albeit mixed, evidence that supports possible beneficial effects on skeletal muscle function for some classes of drugs used to treat diabetes, including metformin and SGLT2 inhibitors. Most human observational and intervention evidence for the effects of these drugs has been derived from populations with type 2 diabetes mellitus, and there is a need for intervention studies for older people with, and at risk of, sarcopenia to further investigate the balance of benefit and risk in these target populations. Not all diabetes treatments will be safe to use in those without diabetes because of variable side effects across classes. However, some agents [including glucagon-like peptide (GLP)-1 receptor agonists and SGLT2 inhibitors] have already demonstrated benefits in populations without diabetes, and it is these agents, along with metformin, that hold out the most promise for further investigation in sarcopenia.

Association of metformin exposure with low risks of frailty and adverse outcomes in patients with diabetes

BACKGROUND

Diabetes is an independent risk factor of frailty, which increases adverse outcomes in patients with diabetes. Metformin is a common antidiabetic drug in clinical practice. Insulin resistance and chronic inflammation are the two common mechanisms of diabetes and frailty, as well as the main targets of metformin. Research suggested that metformin has anti-aging potential. However, few studies focus on the relationship between metformin and frailty. Thus, we aimed to explore whether metformin was associated with a low risk of frailty and other adverse outcomes in diabetic patients.

METHODS

A total of 422 patients (≥ 40 years old) with type 2 diabetes were recruited. Frailty was defined by the Fried phenotype. General information and metformin exposure data were collected, and comprehensive geriatric assessment and laboratory tests were performed. Follow-up was conducted after 4.5 years. The primary outcome was the combined endpoint of cardiovascular events, cerebrovascular events, readmission, and death. Binary logistic regression analysis was used to analyze the association of metformin with frailty. Survival analysis was performed using Cox proportional hazards models.

RESULTS

The total prevalence of frailty was 19.4% among the participants with diabetes. 13.1% of patients in the metformin group and 28.2% in the non-metformin group had frailty. Metformin was inversely associated with frailty after adjusting for age, sex, duration, blood glucose levels, target organ damage, comorbidities, and polypharmacy. Further longitudinal analysis showed that metformin was also independently associated with a low risk of combined primary outcomes after adjusting for multiple covariables, while frailty was related to an increased risk of the combined primary outcomes. In the non-frail group, metformin was associated with a decreased risk of combined primary outcomes after adjustment for age and sex. However, the protective effect of metformin on adverse outcomes was not found in frail participants with diabetes.

CONCLUSIONS

Metformin use is associated with a reduced risk of frailty. In addition, frailty may attenuate the protective effects of metformin on adverse outcomes in diabetic patients. The early identification and prevention of frailty progression may help enhance the benefits of metformin in patients with diabetes.