Impact of frailty and its inter-relationship with lean tissue wasting and malnutrition on kidney transplant waitlist candidacy and delisting

Modified creatinine index as a marker of skeletal muscle mass in peritoneal dialysis patients

Background

Sarcopenia is common in peritoneal dialysis (PD) patients. Modified creatinine index (MCrI) by the Canaud's formula and single-pool Kt/V value is an accurate surrogate marker for muscle mass in hemodialysis patients. However, the method of calculation and validity of MCrI has not been tested in PD.

Methods

In the exploratory cohort, we studied 138 consecutive patients converted from PD to hemodialysis. Their MCrI during PD, calculated by the Canaud's formula with total weekly Kt/V, and the conventional MCrI after conversion to HD, were compared by the Bland-Altman method. Their correlation with muscle mass as determined by bioimpedance spectroscopy and creatinine kinetic methods was explored. The result was then validated in a second cohort of 605 incident PD patients.

Results

In the exploratory cohort, the average bias of computing MCrI during PD and hemodialysis was 0.758 mg/kg/day (95%CI -4.356 to 5.873 mg/kg/day). The MCrI during PD significantly correlated with the muscle mass by creatinine kinetics (r = .684, P < .0001) and by bioimpedance spectroscopy (r = .641, P < .0001), but not with protein nitrogen appearance, overhydration, or adipose tissue mass, and the result was similar in the validation cohort. For incident PD patients, MCrI quartile was significantly associated with the risk of death from all cause in 12 months (Gray's test, P = .013) but not conversion to chronic hemodialysis (P = .14).

Conclusion

In PD patients, MCrI computed by the Canaud's formula and total weekly Kt/V is a simple and reliable marker of skeletal muscle mass and may serve as a short-term prognostic indicator.

Frailty in patients on dialysis

Frailty is a condition that is frequently observed among patients undergoing dialysis. Frailty is characterized by a decline in both physiological state and cognitive state, leading to a combination of symptoms, such as weight loss, exhaustion, low physical activity level, weakness, and slow walking speed. Frail patients not only experience a poor quality of life, but also are at higher risk of hospitalization, infection, cardiovascular events, dialysis-associated complications, and death. Frailty occurs as a result of a combination and interaction of various medical issues in patients who are on dialysis. Unfortunately, frailty has no cure. To address frailty, a multifaceted approach is necessary, involving coordinated efforts from nephrologists, geriatricians, nurses, allied health practitioners, and family members. Strategies such as optimizing nutrition and chronic kidney disease-related complications, reducing polypharmacy by deprescription, personalizing dialysis prescription, and considering home-based or assisted dialysis may help slow the decline of physical function over time in subjects with frailty. This review discusses the underlying causes of frailty in patients on dialysis and examines the methods and difficulties involved in managing frailty among this group.

Pretransplant Malnutrition, Particularly With Muscle Depletion Is Associated With Adverse Outcomes After Kidney Transplantation

Background

Kidney transplant centers lack consistent diagnostic malnutrition tools. The Academy of Nutrition and Dietetics and American Society of Parenteral Nutrition Adult Malnutrition Criteria (AMC) is the widely accepted and utilized tool by Registered Dietitian Nutritionists (RDNs) to diagnose malnutrition.

Methods

In this single-center, retrospective observational study, we evaluated the outcomes of prekidney transplant malnutrition based on Academy of Nutrition and Dietetics and American Society of Parenteral Nutrition AMC, as well as the individual components of the AMC, on posttransplant outcomes including length of stay, delayed graft function (DGF), early readmission, cardiovascular events, acute rejection, death-censored graft failure, and death. Bivariable and multivariable logistic regression models were used to assess the association of malnutrition or its components with outcomes of interest.

Results

A total of 367 recipients were included, of whom 36 (10%) were malnourished (23 moderately and 13 severely) at pretransplant evaluation. In adjusted models, pretransplant malnutrition was significantly associated with increased risk for early readmission (adjusted odds ratio 2.86; 95% confidence interval: 1.14-7.21; P = 0.03) and with DGF (adjusted odds ratio 8.33; 95% confidence interval: 1.07-64.6; P = 0.04). Muscle depletion was also associated with an increased risk for readmission and with DGF. Fat depletion and reduced functionality in the adjusted model were only associated with increased risk for readmission.

Conclusions

Malnutrition could be an important consideration for selecting kidney transplant recipients because it was associated with poor clinical outcomes. A multidisciplinary approach with the involvement of RDNs to outline a nutrition intervention plan may help mitigate some of the poor outcomes.

Latest advances in frailty in kidney transplantation: A narrative review

Frailty is a clinical syndrome that is characterised by decline in multiple systems with associated decreased physiological reserve and ability to respond to stressor events. It is associated with greater healthcare burden. It is common in patients with end-stage renal disease (ESRD). Kidney transplantation is considered the optimal form of renal replacement therapy for suitable patients with ESRD. However, surgery and immunosuppression are physiological stresses that can disproportionately affect frail individuals. Frailty is emerging as a potentially important risk factor in patients waitlisted for kidney transplantation. Most of the published research to date in this area comes from a single transplant centre in the USA. Frailty, as measured using the Physical Frailty Phenotype (FP), is prevalent in waitlisted patients and has been associated with early hospital re-admission, prolonged length of stay, delayed graft function and increased mortality after kidney transplantation. However, although kidney transplantation is a substantial physiological stress to a patient's reserve, by restoring kidney function, kidney transplantation has also been shown to improve a patient's frailty status. The FP is the most studied tool in patients waitlisted for transplantation, but it has not been able to distinguish those whose frailty is improved by kidney transplantation. In summary, there remain significant gaps in knowledge and uncertainties as to how to effectively use existing frailty measures to inform decision-making around kidney transplantation. Further research is needed to address these important gaps in the literature.

Narrative Review: Clinical Implications and Assessment of Frailty in Patients With Advanced CKD

Frailty is a multidimensional clinical syndrome characterized by low physical activity, reduced strength, accumulation of multiorgan deficits, decreased physiological reserve, and vulnerability to stressors. Frailty has key social, psychological, and cognitive implications. Frailty is accelerated by uremia, leading to a high prevalence of frailty in patients with advanced chronic kidney disease (CKD) and end-stage kidney disease (ESKD) as well as contributing to adverse outcomes in this patient population. Frailty assessment is not routine in patients with CKD; however, a number of validated clinical assessment tools can assist in prognostication. Frailty assessment in nephrology populations supports shared decision-making and advanced communication and should inform key medical transitions. Frailty screening and interventions in CKD or ESKD are a developing research priority with a rapidly expanding literature base.

Dietary Micronutrient Intake and Its Relationship with the Malnutrition-Inflammation-Frailty Complex in Patients Undergoing Peritoneal Dialysis

BACKGROUND

The relationship between dietary patterns and the malnutrition-inflammation-frailty complex in patients undergoing peritoneal dialysis (PD) is currently unknown. Our objective was to measure dietary nutrient intake and evaluate its association with malnutrition, inflammation, and frailty.

METHODS

We prospectively recruited adult PD patients. We assessed their dietary nutrient intake using a food frequency questionnaire. Frailty, malnutrition, and inflammation were evaluated by validated Frailty Score (FQ), Subjective Global Assessment (SGA), and Malnutrition-Inflammation Score (MIS).

RESULTS

A total of 209 patients were recruited for the study. Among them, 89 patients (42.6%) had an insufficient protein intake, and 104 patients (49.8%) had an insufficient energy intake. Additionally, 127 subjects were identified as frail, characterized by being older (61.9 ± 9.5 vs. 55.6 ± 12.8, p < 0.001), malnourished (SGA: 21.0 ± 2.7 vs. 22.7 ± 3.1, p < 0.001), and having a high inflammation burden (MIS: 10.55 ± 3.72 vs. 7.18 ± 3.61, p < 0.001). There was a significant correlation between dietary zinc intake and body mass index (r = 0.31, p < 0.001), SGA (r = 0.22, p = 0.01), and MIS (r = -0.22, p = 0.01). In the multivariate model, a higher dietary zinc intake predicted a higher SGA (beta 0.03, p = 0.003) and lower FQ (beta -0.38, p < 0.001) and MIS (beta -0.14, p < 0.001), indicating a better nutrition, less frail and inflamed state. A higher dietary zinc intake was also associated with a lower odds of being frail (adjusted odds ratio 0.96, p = 0.009).

CONCLUSION

Dietary inadequacy and micronutrient deficiency are common among the PD population. Dietary zinc intake is independently associated with an improved nutrition, physical condition, and reduced inflammatory state.

Malnutrition in solid organ transplant patients: A review of the literature

Screening for malnutrition is of vital importance for solid organ transplant candidates to optimize nutrition status before transplant, to improve clinical outcomes and to inform selection committees of nutritional contraindications and risks. There are multiple criteria and screening tools available for determining malnutrition diagnosis and risk. Registered Dietitian Nutritionists use these tools for nutrition assessments to quantify the severity of malnutrition, provide patient-centered interventions, and monitor progression. Many transplant centers in the United States utilize the American Society of Parenteral and Enteral Nutrition and the Academy of Nutrition and Dietetics' Adult Malnutrition Criteria, though there is limited research using these criteria specifically in the transplant population. Malnutrition, utilizing other diagnostic and screening tools, has been associated with important complications, including longer length of hospital stay, increased mortality, decreased quality of life, worsened end-stage organ progression, and decreased functional status. Malnutrition typically results from sarcopenia and cachexia, and can ultimately lead to frailty, causing further negative impacts on transplant outcomes. This literature review summarizes the current research on malnutrition in solid organ transplant candidates and provides recommendations for future research and current practice implications.

Interpretations of the Role of Plasma Albumin in Prognostic Indices: A Literature Review

This review assesses how publications interpret factors that influence the serum or plasma albumin (PA) level in prognostic indices, focusing on inflammation and nutrition. On PubMed, a search for "albumin AND prognosis" yielded 23,919 results. From these records, prognostic indices were retrieved, and their names were used as search strings on PubMed. Indices found in 10 or more original research articles were included. The same search strings, restricted to "Review" or "Systematic review", retrieved yielded on the indices. The data comprised the 10 latest original research articles and up to 10 of the latest reviews. Thirty indices had 294 original research articles (6 covering two indices) and 131 reviews, most of which were from recent years. A total of 106 articles related the PA level to inflammation, and 136 related the PA level to nutrition. For the reviews, the equivalent numbers were 54 and 65. In conclusion, more publications mention the PA level as a marker of nutrition rather than inflammation. This is in contrast to several general reviews on albumin and nutritional guidelines, which state that the PA level is a marker of inflammation but not nutrition. Hypoalbuminemia should prompt clinicians to focus on the inflammatory aspects in their patients.

Use of frailty assessment instruments in nephrology populations: a scoping review

BACKGROUND

Frailty is a clinical syndrome of accelerated aging associated with adverse outcomes. Frailty is prevalent among patients with chronic kidney disease but is infrequently assessed in clinical settings, due to lack of consensus regarding frailty definitions and diagnostic tools. This study aimed to review the practice of frailty assessment in nephrology populations and evaluate the context and timing of frailty assessment.

METHODS

The search included published reports of frailty assessment in patients with chronic kidney disease, undergoing dialysis or in receipt of a kidney transplant, published between January 2000 and November 2021. Medline, CINAHL, Embase, PsychINFO, PubMed and Cochrane Library databases were examined. A total of 164 articles were included for review.

RESULTS

We found that studies were most frequently set within developed nations. Overall, 161 studies were frailty assessments conducted as part of an observational study design, and 3 within an interventional study. Studies favoured assessment of participants with chronic kidney disease (CKD) and transplant candidates. A total of 40 different frailty metrics were used. The most frequently utilised tool was the Fried frailty phenotype. Frailty prevalence varied across populations and research settings from 2.8% among participants with CKD to 82% among patients undergoing haemodialysis. Studies of frailty in conservatively managed populations were infrequent (N = 4). We verified that frailty predicts higher rates of adverse patient outcomes. There is sufficient literature to justify future meta-analyses.

CONCLUSIONS

There is increasing recognition of frailty in nephrology populations and the value of assessment in informing prognostication and decision-making during transitions in care. The Fried frailty phenotype is the most frequently utilised assessment, reflecting the feasibility of incorporating objective measures of frailty and vulnerability into nephrology clinical assessment. Further research examining frailty in low and middle income countries as well as first nations people is required. Future work should focus on interventional strategies exploring frailty rehabilitation.

From MIA to FIFA: The vicious matrix of frailty, inflammation, fluid overload and atherosclerosis in peritoneal dialysis

Cardiovascular disease (CVD) is a major cause of mortality and morbidity in peritoneal dialysis (PD) patients. Two decades ago, the common co-existence of malnutrition and systemic inflammation PD patients with atherosclerosis and CVD led to the proposed terminology of 'malnutrition-inflammation-atherosclerosis (MIA) syndrome'. Although the importance of malnutrition is well accepted, frailty represents a more comprehensive assessment of the physical and functional capability of the patient and encompasses the contributions of sarcopenia (a key component of malnutrition), obesity, cardiopulmonary as well as neuropsychiatric impairment. In recent years, it is also increasingly recognized that fluid overload is not only the consequence but also play an important role in the pathogenesis of CVD. Moreover, fluid overload is closely linked with the systemic inflammatory status, presumably by gut oedema, gastrointestinal epithelial barrier dysfunction and leakage of bacterial fragments to the systemic circulation. There are now a wealth of published evidence to show intricate relations between frailty, inflammation, fluid overload and atherosclerotic disease in patients with chronic kidney disease (CKD) and those on PD, a phenomenon that we propose the term 'FIFA complex'. In this system, frailty and atherosclerotic disease may be regarded as two patient-oriented outcomes, while inflammation and fluid overload are two inter-connected pathogenic processes. However, there remain limited data on how the treatment of one component affect the others. It is also important to define how treatment of fluid overload affect the systemic inflammatory status and to develop effective anti-inflammatory strategies that could alleviate atherosclerotic disease and frailty.

Frailty and solid-organ transplant candidates: a scoping review

BACKGROUND

There is currently no consensus as to a standardized tool for frailty measurement in any patient population. In the solid-organ transplantation population, routinely identifying and quantifying frailty in potential transplant candidates would support patients and the multidisciplinary team to make well-informed, individualized, management decisions. The aim of this scoping review was to synthesise the literature regarding frailty measurement in solid-organ transplant (SOT) candidates.

METHODS

A search of four databases (Cochrane, Pubmed, EMBASE and CINAHL) yielded 3124 studies. 101 studies (including heart, kidney, liver, and lung transplant candidate populations) met the inclusion criteria.

RESULTS

We found that studies used a wide range of frailty tools (N = 22), including four 'established' frailty tools. The most commonly used tools were the Fried Frailty Phenotype and the Liver Frailty Index. Frailty prevalence estimates for this middle-aged, predominantly male, population varied between 2.7% and 100%. In the SOT candidate population, frailty was found to be associated with a range of adverse outcomes, with most evidence for increased mortality (including post-transplant and wait-list mortality), post-operative complications and prolonged hospitalisation. There is currently insufficient data to compare the predictive validity of frailty tools in the SOT population.

CONCLUSION

Overall, there is great variability in the approach to frailty measurement in this population. Preferably, a validated frailty measurement tool would be incorporated into SOT eligibility assessments internationally with a view to facilitating comparisons between patient sub-groups and national and international transplant services with the ultimate goal of improved patient care.

Kidney Organ Allocation System: How to Be Fair

Transplantation is a life-saving medical intervention that unfortunately is constrained by scarcity of available organs. An ideal system for allocating organs should seek to achieve the greatest good for the greatest number of people. It also must be fair and not disadvantage certain populations. However, policies aimed at reducing disparities also must be balanced with considerations of utility (graft outcomes), cost, efficiency, and any adverse effects on organ utilization. Here, we discuss the ethical challenges of creating a fair and equitable organ allocation system, focusing on the principles governing deceased donor kidney transplant waitlists around the world. The kidney organ allocation systems in the United States, Australia, and Hong Kong are used as illustrations.

Polypharmacy Predicts Onset and Transition of Frailty, Malnutrition, and Adverse Outcomes in Peritoneal Dialysis Patient

BACKGROUND

Polypharmacy, frailty and malnutrition are known predictors of adverse outcomes in dialysis patients. Little has reported about their interaction and composite prognostic values. We aimed to describe the interaction between polypharmacy, frailty, nutrition, hospitalization, and survival in peritoneal dialysis patients.

METHODS

In this prospective cohort study, we recruited 573 peritoneal dialysis patients. Drug burden was measured by medication number and daily pill load. Frailty and nutrition were assessed by the validated Frailty Score (FQ) and Subjective Global Assessment (SGA) respectively. All patients were followed for two years. Primary outcome was all-cause mortality. Secondary outcomes were fall and fracture episodes, hospitalization, change in FQ and SGA.

RESULTS

At baseline, each patient took 7.5 ± 2.6 medications with 15.5 ± 8.5 tablets per day. Medication number, but not daily pill load predicted baseline FQ (p = 0.004) and SGA (p = 0.03). Over 2 years, there were 69 fall and 1,606 hospitalization episodes. In addition, 148 (25.8%) patients died, while FQ and SGA changed by 0.73 ± 4.23 and -0.07 ± 1.06 respectively in survivors. Medication number (hospitalization: p = 0.02, survival: p = 0.005), FQ (hospitalization: p < 0.001; survival: p = 0.01) predicted hospitalization and survival. Medication number also predicted fall episodes (p = 0.02) and frailty progression (p = 0.002). Daily pill load did not predict any of these outcomes.

CONCLUSIONS

Drug burden is high in peritoneal dialysis patients, and it carries important prognostic implication. Medication number but not pill load significantly predicted onset and progression of frailty, malnutrition, fall, hospitalization, and mortality.