Weight loss is the hallmark of any progressive acute or chronic disease state. In its extreme form of significant lean body mass (including skeletal muscle) and fat loss, it is referred to as cachexia. It has been known for millennia that muscle and fat wasting leads to poor outcomes including death. On one hand, conditions and risk factors that lead to cachexia and inadequate nutrition may independently lead to increased mortality. Additionaly, cachexia per se, withdrawal of nutritional support in progressive cachexia, and advanced age may lead to death via cachexia-specific pathways. Despite the strong and consistent association of cachexia with mortality, no unifying mechanism has yet been suggested as to why wasting conditions are associated with an exceptionally high mortality risk. Hence, the causality of the cachexia-death association, even though it is biologically plausible, is widely unknown. This century-long uncertainty may have played a role as to why the field of cachexia treatment development has not shown major advances over the past decades. We suggest that cachexia-associated relative thrombocytosis and platelet activation may play a causal role in cachexia-related death, while other mechanisms may also contribute including arrhythmia-associated sudden deaths, endocrine disorders such as hypothyroidism, and immune system compromise leading to infectious events and deaths. Multidimensional research including examining biologically plausible models is urgently needed to investigate the causality of the cachexia-death association.

Currently, there are 5 million individuals with chronic heart failure (CHF) in the United States who have poor clinical outcomes, including high death rates. Observational studies have indicated a reverse epidemiology of traditional cardiovascular risk factors in CHF; in contrast to trends seen in the general population, obesity and hypercholesterolemia are associated with improved survival. The temporal discordance between the overnutrition (long-term killer) and undernutrition (short-term killer) not only can explain some of the observed paradoxes but also may indicate that malnutrition, inflammation, and oxidative stress may play a role that results in protein-energy wasting contributing to poor survival in CHF. Diminished appetite or anorexia and nutritional deficiencies may be both a cause and a consequence of this so-called malnutrition-inflammation-cachexia (MIC) or wasting syndrome in CHF. Neurohumoral activation, insulin resistance, cytokine activation, and survival selection-resultant genetic polymorphisms also may contribute to the prominent inflammatory and oxidative characteristics of this population. In patients with CHF and wasting, nutritional strategies including amino acid supplementation may represent a promising therapeutic approach, especially if the provision of additional amino acids, protein, and energy includes nutrients with anti-inflammatory and antioxidant properties. Regardless of the etiology of anorexia, appetite-stimulating agents, especially those with anti-inflammatory properties such as megesterol acetate or pentoxyphylline, may be appropriate adjuncts to dietary supplementation. Understanding the factors that modulate MIC and body wasting and their associations with clinical outcomes in CHF may lead to the development of nutritional strategies that alter the pathophysiology of CHF and improve outcomes.

Sarcopenia or muscle wasting is a progressive and generalized skeletal muscle disorder involving the accelerated loss of muscle mass and function, often associated with muscle weakness (dynapenia) and frailty. Whereas primary sarcopenia is related to ageing, secondary sarcopenia happens independent of age in the context of chronic disease states such as chronic kidney disease (CKD). Sarcopenia has become a major focus of research and public policy debate due to its impact on patient's health-related quality of life, health-care expenditure, morbidity, and mortality. The development of sarcopenia in patients with CKD is multifactorial and it may occur independently of weight loss or cachexia including under obese sarcopenia. Hormonal imbalances can facilitate the development of sarcopenia in the general population and is a common finding in CKD. Hormones that may influence the development of sarcopenia are testosterone, growth hormone, insulin, thyroid hormones, and vitamin D. Although the relationship between free testosterone level that is low in uraemic patients and sarcopenia in CKD is not well-defined, functional improvement may be seen. Unlike testosterone, it is known that vitamin D is associated with muscle strength, muscle size, and physical performance in patients with CKD. Outcomes after vitamin D replacement therapy are still controversial. The half-life of growth hormone (GH) is prolonged in patients with CKD. Besides, IGF-1 levels are normal in patients with Stage 4 CKD-a minimal reduction is seen in the end-stage renal disease. Unresponsiveness or resistance of IGF-1 and changes in the GH/IGF-1 axis are the main causes of sarcopenia in CKD. Low serum T3 level is frequent in CKD, but the net effect on sarcopenia is not well-studied. CKD patients develop insulin resistance (IR) from the earliest period even before GFR decline begins. IR reduces glucose utilization as an energy source by hepatic gluconeogenesis, decreasing muscle glucose uptake, impairing intracellular glucose metabolism. This cascade results in muscle protein breakdown. IR and sarcopenia might also be a new pathway for targeting. Ghrelin, oestrogen, cortisol, and dehydroepiandrosterone may be other players in the setting of sarcopenia. In this review, we mainly examine the effects of hormonal changes on the occurrence of sarcopenia in patients with CKD via the available data.

Perception of healthy body size and composition differs considerably across the globe, ethnic groups, cultures, and even inside medical community. Although the concept of ideal body weight has evolved over the past decades, the observation that weight loss can have more deleterious effects within a short-term period than weight gain has remained rather consistent. Weight loss, as a prelude to cachexia, occurs frequently in a variety of disease states and meets the requirements of a global public health problem. Consequently, interventions to prevent and control chronic diseases require a comprehensive approach that targets a population as a whole and includes both prevention and treatment strategies. Around the globe, cachexia awareness campaigns and expanding the current public health priorities to highlight the cachexia magnitude and areas of interventions is necessary. Simultaneously, scientific efforts should provide us with more reliable estimates of body wasting and cachexia as well as pathophysiology of cachexia-associated death. As certain proportion of patients will, irrespective of preventive measures, eventually develop cachexia, a quest for effective remedy remains vital.

Cachexia, in the form of unintentional weight loss >5% in 12 months or less, and secondary sarcopenia in the form of muscle wasting are serious conditions that affect clinical outcomes. A chronic disease state such as chronic kidney disease (CKD) often contributes to these wasting disorders. The purpose of this review is to summarize the prevalence of cachexia and sarcopenia, their relationship with kidney function, and indicators for evaluating kidney function in patients with CKD. It is estimated that approximately half of all persons with CKD will develop cachexia with an estimated annual mortality rate of 20%, but few studies have been conducted on cachexia in CKD. Hence, the true prevalence of cachexia in CKD and its effects on kidney function and patient outcomes remain unclear. Some studies have highlighted the concept of protein-energy wasting (PEW) which usually include sarcopenia and cachexia. Several studies have examined kidney function and CKD progression in patients with sarcopenia. Most studies use serum creatinine levels to estimate kidney function. However, creatinine may be influenced by muscle mass, and creatinine-based glomerular filtration rate may overestimate kidney function in patients with reduced muscle mass or muscle wasting. Cystatin C, which is least affected by muscle mass, has been used in some studies, and creatinine-to-cystatin-C ratio has emerged as an important prognostic marker. A previous study incorporating 428 320 participants reported that participants with CKD and sarcopenia had a 33% higher hazard of mortality compared with those without (7% to 66%, P = 0.011), and that those with sarcopenia were twice as likely to develop end-stage kidney disease (hazard ratio: 1.98; 1.45 to 2.70, P < 0.001). Future studies on cachexia and sarcopenia in patients with CKD are needed to report rigorously defined cachexia concerning kidney function. Moreover, in studies on sarcopenia with CKD, it is desirable to accumulate studies using cystatin C to accurately estimate kidney function.

BACKGROUND: Initiation and up-titration of guideline-directed medical therapies (GDMTs) for heart failure with reduced ejection fraction (HFrEF) remains suboptimal, in part because of concerns regarding tolerability and adverse events (AEs). OBJECTIVES: The authors sought to compare rates of AE in patients randomized to GDMT medication vs placebo in a meta-analysis of landmark cardiovascular outcomes trials. METHODS: The authors assessed rates of reported AE in 17 landmark HFrEF clinical trials across each class of GDMT in the placebo and intervention arms. The overall rates of AE for each drug class, the absolute difference in frequency in AEs between the placebo and intervention arms, and the odds of each AE according based on randomization strata were calculated. RESULTS: AE were reported commonly in trials across each class of GDMT, with 75% to 85% of participants reporting at least 1 AE. There was no significant difference in the frequency of AE between the intervention and placebo arms, except for angiotensin-converting enzyme inhibitors (87.0% [95% CI: 85.0%-88.8%] vs 82.0% [95% CI: 79.8%-84.0%], absolute difference: +5% with intervention; P < 0.001). There was no significant difference in drug discontinuation because of AE between placebo and intervention arms in angiotensin-converting enzyme inhibitors, mineralocorticoid receptor antagonists, sodium glucose cotransporter 2 inhibitors, or angiotensin receptor neprilysin inhibitor/angiotensin II receptor blocker trials. Patients randomized to beta-blocker were significantly less likely to stop study drug because of AE than placebo (11.3% [95% CI: 10.3%-12.3%] vs 13.7% [95% CI: 12.5%-14.9%], absolute difference: -1.1%; P = 0.015). When individual types of AE were assessed, the initiation of an intervention vs placebo resulted in small differences in absolute frequency of AE that were largely not statistically significant. CONCLUSIONS: In clinical trials of GDMT for HFrEF, AEs are observed frequently. However, rates of AE are similar between active medication and control, suggesting these may reflect the high risk nature of the heart failure disease state rather than be attributive to a specific therapy.