Frailty, but not cognitive impairment, improves mortality risk prediction among those with chronic kidney disease-a nationally representative study.

BACKGROUND: Though older adults with chronic kidney disease (CKD) have a greater mortality risk than those without CKD, traditional risk factors poorly predict mortality in this population. Therefore, we tested our hypothesis that two common geriatric risk factors, frailty and cognitive impairment, and their co-occurrence, might improve mortality risk prediction in CKD. METHODS: Among participants aged ≥ 60 years from National Health and Nutrition Examination Survey (2011-2014), we quantified associations between frailty (physical frailty phenotype) and global/domain-specific cognitive function (immediate-recall [CERAD-WL], delayed-recall [CERAD-DL], verbal fluency [AF], executive function/processing speed [DSST], and global [standardized-average of 4 domain-specific tests]) using linear regression, and tested whether associations differed by CKD using a Wald test. We then tested whether frailty, global cognitive impairment (1.5SD below the mean), or their combination improved prediction of mortality (Cox models, c-statistics) compared to base models (likelihood-ratios) among those with and without CKD. RESULTS: Among 3,211 participants, 1.4% were cognitively impaired, and 10.0% were frail; frailty and cognitive impairment co-occurrence was greater among those with CKD versus those without (1.2%vs.0.1%). Frailty was associated with worse global cognitive function (Cohen's d = -0.26SD,95%CI -0.36,-0.17), and worse cognitive function across all domains; these associations did not differ by CKD (pinteractions > 0.05). Mortality risk prediction improved only among those with CKD when accounting for frailty (p[likelihood ratio test] < 0.001) but not cognitive impairment. CONCLUSIONS: Frailty is associated with worse cognitive function regardless of CKD status. While CKD and frailty improved mortality prediction, cognitive impairment did not. Risk prediction tools should incorporate frailty to improve mortality prediction among those with CKD.

Sleep duration and cognitive function among older adults with chronic kidney disease: results from the National Health and Nutrition Examination Survey (2011-2014).

BACKGROUND: Short and long sleep durations are associated with cognitive dysfunction. Given the increased prevalence of sleep abnormalities in the chronic kidney disease (CKD) population, we tested whether the association between sleep duration and cognitive function differed between older adults with and without CKD. METHODS: This was a study of 3215 older adults (age ≥60 years) enrolled in the National Health and Nutrition Examination Survey (2011-14) evaluating sleep duration, cognitive function (immediate recall, delayed recall, verbal fluency, executive function and processing speed and global cognition) and kidney function. We quantified the association between sleep duration and cognitive function using linear regression and tested whether the associations differed among those with CKD and without using a Wald test for interaction. RESULTS: Among 3215 participants, 13.3% reported 2-5 hours of sleep/day, 75.2% reported 6-8 hours, and 11.5% reported ≥9 hours. Persons with CKD were more likely to sleep ≥9 hours [odds ratio 1.73 (95% confidence interval 1.22-2.46)]. Among participants with CKD, those with a sleep duration ≥9 hours demonstrated worse global cognitive function (P for interaction = .01), immediate recall (P for interaction = .01) and verbal fluency (P for interaction = .004) than those with a sleep duration of 6-8 h; no differences were observed for participants with CKD who slept 2-5 hours. Among participants without CKD, sleep was not associated with any measures of cognitive function. CONCLUSIONS: Longer sleep duration is associated with worse cognitive function only among persons with CKD, and global cognition, delayed recall and verbal fluency are particularly affected. Studies should identify interventions to improve sleep patterns and quality in this population.

Delirium, changes in cognitive function, and risk of diagnosed dementia after kidney transplantation.

Kidney transplant (KT) recipients with delirium, a preventable surgical complication, are likely to reap cognitive benefits from restored kidney function, but may be more vulnerable to longer-term neurotoxic stressors post-KT (i.e., aging, immunosuppression). In this prospective cohort study, we measured delirium (chart-based), global cognitive function (3MS), and executive function (Trail Making Test Part B minus Part A) in 894 recipients (2009-2021) at KT, 1/3/6-months, 1-year, and annually post-KT. Dementia was ascertained using linked Medicare claims. We described repeated measures of cognitive performance (mixed effects model) and quantified dementia risk (Fine & Gray competing risk) by post-KT delirium. Of 894 recipients, 43(4.8%) had post-KT delirium. Delirium was not associated with global cognitive function at KT (difference = -3.2 points, 95%CI: -6.7, 0.4) or trajectories post-KT (0.03 points/month, 95%CI: -0.27, 0.33). Delirium was associated with worse executive function at KT (55.1 s, 95%CI: 25.6, 84.5), greater improvements in executive function <2 years post-KT (-2.73 s/month, 95%CI: -4.46,-0.99), and greater decline in executive function >2 years post-KT (1.72 s/month, 95%CI: 0.22, 3.21). Post-KT delirium was associated with over 7-fold greater risk of dementia post-KT (adjusted subdistribution hazard ratio = 7.84, 95%CI: 1.22, 50.40). Transplant centers should be aware of cognitive risks associated with post-KT delirium and implement available preventative interventions to reduce delirium risk.

Domains for a Comprehensive Geriatric Assessment of Older Adults with Chronic Kidney Disease: Results from the CRIC Study.

INTRODUCTION: A comprehensive geriatric assessment (CGA) tailored to the chronic kidney disease (CKD) population would yield a more targeted approach to assessment and care. We aimed to identify domains of a CKD-specific CGA (CKD-CGA), characterize patterns of these domains, and evaluate their predictive utility on adverse health outcomes. METHODS: We used data from 864 participants in the Chronic Renal Insufficiency Cohort aged ≥55 years and not on dialysis. Constituents of the CKD-CGA were selected a priori. Latent class analysis informed the selection of domains and identified classes of participants based on their domain patterns. The predictive utility of class membership on mortality, dialysis initiation, and hospitalization was examined. Model discrimination was assessed with C-statistics. RESULTS: The CKD-CGA included 16 domains: cardiovascular disease, diabetes, five frailty phenotype components, depressive symptoms, cognition, five kidney disease quality-of-life components, health literacy, and medication use. A two-class latent class model fit the data best, with 34.7% and 65.3% in the high- and low-burden of geriatric conditions classes, respectively. Relative to the low-burden class, participants in the high-burden class were at increased risk of mortality (aHR = 2.09; 95% CI: 1.56, 2.78), dialysis initiation (aHR = 1.63; 95% CI: 1.06, 2.52), and hospitalization (aOR = 2.00; 95% CI: 1.38, 2.88). Model discrimination was the strongest for dialysis initiation (C-statistics = 0.86) and moderate for mortality and hospitalization (C-statistics = 0.70 and 0.66, respectively). CONCLUSION: With further validation in an external cohort, the CKD-CGA has the potential to be used in nephrology practices for assessing and managing geriatric conditions in older adults with CKD.

Secondary hyperparathyroidism (CKD-MBD) treatment and the risk of dementia.

BACKGROUND: Elevated parathyroid hormone (PTH) levels have been reported as a potential risk factor for cognitive impairment. Compared with the general population, older adults with end-stage renal disease (ESRD) who are frequently affected by secondary hyperparathyroidism (SHPT) are at increased risk of developing dementia. The main objective of our study was to evaluate if the risk of dementia in older (age ≥66 years) ESRD patients differed if they were treated for SHPT. METHODS: Using the United States Renal Data System and Medicare claims, we identified 189 433 older adults without a diagnosis of dementia, who initiated dialysis between 2006 and 2016. SHPT treatment was defined as the use of vitamin D analogs, phosphate binders, calcimimetics or parathyroidectomy. We quantified the association between treated SHPT and incident dementia during dialysis using a multivariable Cox proportional hazards model with inverse probability weighting, considering SHPT treatment as a time-varying exposure. RESULTS: Of 189 433 older ESRD adults, 92% had a claims diagnosis code of SHPT and 123 388 (65%) were treated for SHPT. The rate of incident dementia was 6 cases per 100 person-years among SHPT treated patients compared with 11 cases per 100 person-years among untreated patients. Compared with untreated SHPT patients, the risk of dementia was 42% lower [adjusted hazard ratio (aHR) = 0.58, 95% confidence interval (CI): 0.56-0.59] among SHPT treated patients. The magnitude of the beneficial effect of SHPT treatment differed by sex (Pinteraction = .02) and race (Pinteraction ≤ .01), with females (aHR = 0.56, 95% CI: 0.54-0.58) and those of Asian (aHR = 0.51, 95% CI: 0.46-0.57) or Black race (aHR = 0.51, 95% CI: 0.48-0.53) having a greatest reduction in dementia risk. CONCLUSION: Receiving treatment for SHPT was associated with a lower risk of incident dementia among older patients with ESRD. This work provides additional support for the treatment of SHPT in older ESRD patients.

Chronic kidney disease, physical activity and cognitive function in older adults-results from the National Health and Nutrition Examination Survey (2011-2014).

BACKGROUND: Cognitive impairment is common among persons with chronic kidney disease (CKD), due in part to reduced kidney function. Given that physical activity (PA) is known to mitigate cognitive decline, we examined whether associations between CKD stage and global/domain-specific cognitive function differ by PA. METHODS: We leveraged 3223 participants (≥60 years of age) enrolled in National Health and Nutrition Examination Survey (NHANES, 2011-2014), with at least one measure of objective cognitive function [immediate recall (CERAD-WL), delayed recall (CERAD-DR), verbal fluency (AF), executive function/processing speed (DSST), global (average of four tests) or self-perceived memory decline (SCD)]. We quantified the association between CKD stage {no CKD: estimated glomerular filtration rate [eGFR] ≥60 mL/min/1.73 m2 and albuminuria [albumin:creatinine ratio (ACR)] <30 mg/g; stages G1-G3: eGFR ≥60 mL/min/1.73 m2 and ACR ≥30 mg/g or eGFR 30-59 mL/min/1.73 m2; stages G4 and G5: eGFR <30 mL/min/1.73 m2} and cognitive function using linear regression (objective measures) and logistic regression (SCD), accounting for sampling weights for nationally representative estimates. We tested whether associations differed by PA [Global Physical Activity Questionnaire, high PA ≥600 metabolic equivalent of task (MET) · min/week versus low PA <600 MET · min/week] using a Wald test. RESULTS: Among NHANES participants, 34.9% had CKD stages G1-G3, 2.6% had stages G4 and G5 and 50.7% had low PA. CKD stages G4 and G5 were associated with lower global cognitive function {difference = -0.38 standard deviation [SD] [95% confidence interval (CI) -0.62 to -0.15]}. This association differed by PA (Pinteraction = 0.01). Specifically, among participants with low PA, those with CKD stages G4 and G5 had lower global cognitive function [difference = -0.57 SD (95% CI -0.82 to -0.31)] compared with those without CKD. Among those with high PA, no difference was found [difference = 0.10 SD (95% CI -0.29-0.49)]. Similarly, the CKD stage was only associated with immediate recall, verbal fluency, executive function and processing speed among those with low PA; no associations were observed for delayed recall or self-perceived memory decline. CONCLUSIONS: CKD is associated with lower objective cognitive function among those with low but not high PA. Clinicians should consider screening older patients with CKD who have low PA for cognitive impairment and encourage them to meet PA guidelines.

Transplant centers that assess frailty as part of clinical practice have better outcomes.

BACKGROUND: Frailty predicts adverse post-kidney transplant (KT) outcomes, yet the impact of frailty assessment on center-level outcomes remains unclear. We sought to test whether transplant centers assessing frailty as part of clinical practice have better pre- and post-KT outcomes in all adult patients (≥18 years) and older patients (≥65 years). METHODS: In a survey of US transplant centers (11/2017-4/2018), 132 (response rate = 65.3%) centers reported their frailty assessment practices (frequency and specific tool) at KT evaluation and admission. Assessment frequency was categorized as never, sometime, and always; type of assessment tool was categorized as none, validated (for post-KT risk prediction), and any other tool. Center characteristics and clinical outcomes for adult patients during 2017-2019 were gleaned from the transplant national registry (Scientific Registry of Transplant Recipients). Poisson regression was used to estimate incidence rate ratios (IRRs) of waitlist outcomes (waitlist mortality, transplantation) in candidates and IRRs of post-KT outcomes (all-cause mortality, death-censored graft loss) in recipients by frailty assessment frequency. We also estimated IRRs of waitlist outcomes by type of assessment tool at evaluation. All models were adjusted for case mix and center characteristics. RESULTS: Assessing frailty at evaluation was associated with lower waitlist mortality rate (always IRR = 0.91,95%CI:0.84-0.99; sometimes = 0.89,95%CI:0.83-0.96) and KT rate (always = 0.94,95%CI:0.91-0.97; sometimes = 0.88,95%CI:0.85-0.90); the associations with waitlist mortality rate (always = 0.86,95%CI:0.74-0.99; sometimes = 0.83,95%CI:0.73-0.94) and KT rate (always = 0.82,95%CI:0.77-0.88; sometimes = 0.92,95%CI:0.87-0.98) were stronger in older patients. Furthermore, using validated (IRR = 0.90,95%CI:0.88-0.92) or any other tool (IRR = 0.90,95%CI:0.87-0.93) at evaluation was associated lower KT rate, while only using a validated tool was associated with lower waitlist mortality rate (IRR = 0.89,95%CI:0.83-0.96), especially in older patients (IRR = 0.82,95%CI:0.72-0.93). At admission for KT, always assessing frailty was associated with a lower graft loss rate (IRR = 0.71,95%CI:0.54-0.92) but not with mortality (IRR = 0.93,95%CI:0.76-1.13). CONCLUSIONS: Assessing frailty at evaluation is associated with lower KT rate, while only using a validated frailty assessment tool is associated with better survival, particularly in older candidates. Centers always assessing frailty at admission are likely to have better graft survival rates. Transplant centers may utilize validated frailty assessment tools to secure KT access for appropriate candidates and to better allocate health care resources for patients identified as frail, particularly for older patients.

Ambient Air Pollution and Mortality among Older Patients Initiating Maintenance Dialysis.

BACKGROUND: Fine particulate matter (particulate matter with diameter <2.5 µm [PM2.5]) is associated with CKD progression and may impact the health of patients living with kidney failure. While older (aged ≥65 years) adults are most vulnerable to the impact of PM2.5, it is unclear whether older patients on dialysis are at elevated risk of mortality when exposed to fine particulate matter. METHODS: Older adults initiating dialysis (2010-2016) were identified from US Renal Data System (USRDS). PM2.5 concentrations were obtained from NASA's Socioeconomic Data and Application Center (SEDAC) Global Annual PM2.5 Grids. We investigated the association between PM2.5 and all-cause mortality using Cox proportional hazard models with linear splines [knot at the current Environmental Protection Agency (EPA) National Ambient Air Quality Standard for PM2.5 of 12 µg/m3] and robust variance. RESULTS: For older dialysis patients who resided in areas with high PM2.5, a 10 µg/m3 increase in PM2.5 was associated with 1.16-fold (95% CI: 1.08-1.25) increased risk of mortality; furthermore, those who were female (aHR = 1.26, 95% CI: 1.13-1.42), Black (aHR = 1.31, 95% CI: 1.09-1.59), or had diabetes as a primary cause of kidney failure (aHR = 1.25, 95% CI: 1.13-1.38) were most vulnerable to high PM2.5. While the mortality risk associated with PM2.5 was stronger at higher levels (aHR = 1.19, 95% CI: 1.08-1.32), at lower levels (≤12 µg/m3), PM2.5 was significantly associated with mortality risk (aHR = 1.04, 95% CI: 1.00-1.07) among patients aged ≥75 years (Pslope difference = 0.006). CONCLUSIONS: Older adults initiating dialysis who resided in ZIP codes with PM2.5 levels >12 µg/m3 are at increased risk of mortality. Those aged >75 were at elevated risk even at levels below the EPA Standard for PM2.5.

Pre-kidney transplant unintentional weight loss leads to worse post-kidney transplant outcomes.

BACKGROUND: Weight loss before kidney transplant (KT) is a known risk factor for weight gain and mortality, however, while unintentional weight loss is a marker of vulnerability, intentional weight loss might improve health. We tested whether pre-KT unintentional and intentional weight loss have differing associations with post-KT weight gain, graft loss and mortality. METHODS: Among 919 KT recipients from a prospective cohort study, we used adjusted mixed-effects models to estimate post-KT BMI trajectories, and Cox models to estimate death-uncensored graft loss, death-censored graft loss and all-cause mortality by 1-year pre-KT weight change category [stable weight (change ≤ 5%), intentional weight loss (loss > 5%), unintentional weight loss (loss > 5%) and weight gain (gain > 5%)]. RESULTS: The mean age was 53 years, 38% were Black and 40% were female. In the pre-KT year, 62% of recipients had stable weight, 15% had weight gain, 14% had unintentional weight loss and 10% had intentional weight loss. In the first 3 years post-KT, BMI increases were similar among those with pre-KT weight gain and intentional weight loss and lower compared with those with unintentional weight loss {difference +0.79 kg/m2/year [95% confidence interval (CI) 0.50-1.08], P < 0.001}. Only unintentional weight loss was independently associated with higher death-uncensored graft loss [adjusted hazard ratio (aHR) 1.80 (95% CI 1.23-2.62)], death-censored graft loss [aHR 1.91 (95% CI 1.12-3.26)] and mortality [aHR 1.72 (95% CI 1.06-2.79)] relative to stable pre-KT weight. CONCLUSIONS: This study suggests that unintentional, but not intentional, pre-KT weight loss is an independent risk factor for adverse post-KT outcomes.

Cognitive impairment burden in older and younger adults across the kidney transplant care continuum.

BACKGROUND: Younger kidney transplant (KT) candidates and recipients may have cognitive impairment due to chronic diseases and reliance on dialysis. METHODS: To quantify cognitive impairment burden by age across the KT care continuum, we leveraged a two-center cohort study of 3854 KT candidates at evaluation, 1114 recipients at admission, and 405 recipients at 1-year post-KT with measured global cognitive performance (3MS) or executive function (Trail Making Test). We also estimated burden of severe cognitive impairment that affects functional dependence (activities of daily living [ADL] < 6 or instrumental activities of daily living [IADL] < 8). RESULTS: Among KT candidates, global cognitive impairment (18-34 years: 11.1%; 35-49 years: 14.0%; 50-64 years: 19.5%; ≥65 years: 22.0%) and severe cognitive impairment burden (18-34 years: 1.1%; 35-49 years: 3.0%; 50-64 years: 6.2%; ≥65 years: 7.7%) increased linearly with age. Among KT recipients at admission, global cognitive impairment (18-34 years: 9.1%; 35-49 years: 6.1%; 50-64 years: 9.3%; ≥65 years: 15.7%) and severe cognitive impairment burden (18-34 years: 1.4%; 35-49 years: 1.4%; 50-64 years: 2.2%; ≥65 years: 4.6%) was lower. Despite lowest burden of cognitive impairment among KT recipients at 1-year post-KT across all ages (18-34 years: 1.7%; 35-49 years: 3.4%; 50-64 years: 4.3%; ≥65 years: 6.5%), many still exhibited severe cognitive impairment (18-34 years: .0%; 35-49 years: 1.9%; 50-64 years: 2.4%; ≥65 years: 3.5%). CONCLUSION: Findings were consistent for executive function impairment. While cognitive impairment increases with age, younger KT candidates have a high burden comparable to community-dwelling older adults, with some potentially suffering from severe forms. Transplant centers should consider routinely screening patients during clinical care encounters regardless of age.

Frailty-a risk factor of global and domain-specific cognitive decline among a nationally representative sample of community-dwelling older adult U.S. Medicare beneficiaries.

OBJECTIVES: frail older adults may be more vulnerable to stressors, resulting in steeper declines in cognitive function. Whether the frailty-cognition link differs by cognitive domain remains unclear; however, it could lend insight into underlying mechanisms. METHODS: we tested whether domain-specific cognitive trajectories (clock-drawing test, (CDT), immediate and delayed recall, orientation to date, time, president and vice-president naming) measured annually (2011-2016) differ by baseline frailty (physical frailty phenotype) in the National Health and Aging Trends Study (n = 7,439), a nationally representative sample of older adult U.S. Medicare beneficiaries, using mixed effects models to describe repeated measures of each cognitive outcome. To determine if the association between frailty and subsequent cognitive change differed by education, we tested for interaction using the Wald test. RESULTS: we observed steeper declines for frail compared to non-frail participants in each domain-specific outcome, except for immediate recall. Largest differences in slope were observed for CDT (difference = -0.12 (standard deviations) SD/year, 95%CI: -0.15, -0.08). By 2016, mean CDT scores for frail participants were 1.8 SD below the mean (95%CI: -1.99, -1.67); for non-frail participants, scores were 0.8 SD below the mean (95%CI: -0.89, -0.69). Associations differed by education for global cognitive function (Pinteraction < 0.001) and for each domain-specific outcome: CDT (Pinteraction < 0.001), orientation (Pinteraction < 0.001), immediate (Pinteraction < 0.001) and delayed (Pinteraction < 0.001) word recalls. CONCLUSION: frailty is associated with lower levels and steeper declines in cognitive function, with strongest associations for executive function. These findings suggest that aetiologies are multifactorial, though primarily vascular related; further research into its association with dementia sub-types and related pathologies is critical.

Prevalence of frailty among kidney transplant candidates and recipients in the United States: Estimates from a National Registry and Multicenter Cohort Study.

Frailty, a measure of physiologic reserve, is associated with poor outcomes and mortality among kidney transplant (KT) candidates and recipients. There are no national estimates of frailty in this population, which may help patient counseling and resource allocation at transplant centers. We studied 4616 KT candidates and 1763 recipients in our multicenter prospective cohort of frailty from 2008-2018 with Fried frailty measurements. Using Scientific Registry of Transplant Recipients (SRTR) data (KT candidates = 560 143 and recipients = 243 508), we projected the national prevalence of frailty (for KT candidates and recipients separately) using standardization through inverse probability weighting, accounting for candidate/recipient, donor, and transplant factors. In our multicenter cohort, 13.3% of KT candidates were frail at evaluation; 8.2% of LDKT recipients and 17.8% of DDKT recipients were frail at transplantation. Projected nationally, our modeling strategy estimated 91 738 KT candidates or 16.4% (95% confidence interval [CI] 14.4%-18.4%) of all KT candidates during the study period were frail, and that 34 822 KT recipients or 14.3% (95% CI 12.3%-16.3%) of all KT recipients were frail (LDKT = 8.2%; DDKT = 17.8%). Given the estimated national prevalence of frailty, transplant programs should consider assessing the condition during KT evaluation to improve patient counseling and resource allocation along with identification of recipients at risk for poor outcomes.

Cognitive Function, Access to Kidney Transplantation, and Waitlist Mortality Among Kidney Transplant Candidates With or Without Diabetes.

RATIONALE & OBJECTIVE: Intact cognition is generally a prerequisite for navigating through and completing evaluation for kidney transplantation. Despite kidney transplantation being contraindicated for those with severe dementia, screening for more mild forms of cognitive impairment before referral is rare. Candidates may have unrecognized cognitive impairment, which may prolong evaluation, elevate mortality risk, and hinder access to kidney transplantation. We estimated the burden of cognitive impairment and its association with access to kidney transplantation and waitlist mortality. STUDY DESIGN: Prospective cohort study. SETTING & PARTICIPANTS: 3,630 participants (January 2009 to June 2018) with cognitive function measured (by the Modified Mini-Mental State Examination [3MS]) at kidney transplantation evaluation at 1 of 2 transplantation centers. PREDICTORS: Cognitive impairment (3MS score<80). OUTCOMES: Listing, waitlist mortality, and kidney transplantation. ANALYTICAL APPROACH: We estimated the adjusted chance of listing (Cox regression), risk for waitlist mortality (competing-risks regression), and kidney transplantation rate (Poisson regression) by cognitive impairment. Given potential differences in cause of cognitive impairment among those with and without diabetes, we tested whether these associations differed by diabetes status using a Wald test. RESULTS: At evaluation, 6.4% of participants had cognitive impairment, which was independently associated with 25% lower chance of listing (adjusted HR, 0.75; 95% CI, 0.61-0.91); this association did not differ by diabetes status (Pinteraction=0.07). There was a nominal difference by diabetes status for the association between cognitive impairment and kidney transplantation rate (Pinteraction=0.05), while the association between cognitive impairment and waitlist mortality differed by diabetes status kidney transplantation rates (Pinteraction=0.02). Among candidates without diabetes, those with cognitive impairment were at 2.47 (95% CI, 1.31-4.66) times greater risk for waitlist mortality; cognitive impairment was not associated with this outcome among candidates with diabetes. LIMITATIONS: Single measure of cognitive impairment. CONCLUSIONS: Cognitive impairment is associated with a lower chance of being placed on the waitlist, and among patients without diabetes, with increased mortality on the waitlist. Future studies should investigate whether implementation of screening for cognitive impairment improves these outcomes.

Frailty Prevalence in Younger End-Stage Kidney Disease Patients Undergoing Dialysis and Transplantation.

BACKGROUND: Frailty, originally characterized in community-dwelling older adults, is increasingly being studied and implemented for adult patients with end-stage kidney disease (ESKD) of all ages (>18 years). Frailty prevalence and manifestation are unclear in younger adults (18-64 years) with ESKD; differences likely exist based on whether the patients are treated with hemodialysis (HD) or kidney transplantation (KT). METHODS: We leveraged 3 cohorts: 378 adults initiating HD (2008-2012), 4,304 adult KT candidates (2009-2019), and 1,396 KT recipients (2008-2019). The frailty phenotype was measured within 6 months of dialysis initiation, at KT evaluation, and KT admission. Prevalence of frailty and its components was estimated by age (≥65 vs. <65 years). A Wald test for interactions was used to test whether risk factors for frailty differed by age. RESULTS: In all 3 cohorts, frailty prevalence was higher among older than younger adults (HD: 71.4 vs. 47.3%; candidates: 25.4 vs. 18.8%; recipients: 20.8 vs. 14.3%). In all cohorts, older patients were more likely to have slowness and weakness but less likely to report exhaustion. Among candidates, older age (odds ratio [OR] = 1.79, 95% CI: 1.47-2.17), non-Hispanic black race (OR = 1.30, 95% CI: 1.08-1.57), and dialysis type (HD vs. no dialysis: OR = 2.06, 95% CI: 1.61-2.64; peritoneal dialysis vs. no dialysis: OR = 1.78, 95% CI: 1.28-2.48) were associated with frailty prevalence, but sex and Hispanic ethnicity were not. These associations did not differ by age (pinteractions > 0.1). Similar results were observed for recipients and HD patients. CONCLUSIONS: Although frailty prevalence increases with age, younger patients have a high burden. Clinicians caring for this vulnerable population should recognize that younger patients may experience frailty and screen all age groups.

Kidney transplant outcomes in recipients with visual, hearing, physical and walking impairments: a prospective cohort study.

BACKGROUND: Disability in general has been associated with poor outcomes in kidney transplant (KT) recipients. However, disability can be derived from various components, specifically visual, hearing, physical and walking impairments. Different impairments may compromise the patient through different mechanisms and might impact different aspects of KT outcomes. METHODS: In our prospective cohort study (June 2013-June 2017), 465 recipients reported hearing, visual, physical and walking impairments before KT. We used hybrid registry-augmented Cox regression, adjusting for confounders using the US KT population (Scientific Registry of Transplant Recipients, N = 66 891), to assess the independent association between impairments and post-KT outcomes [death-censored graft failure (DCGF) and mortality]. RESULTS: In our cohort of 465 recipients, 31.6% reported one or more impairments (hearing 9.3%, visual 16.6%, physical 9.1%, walking 12.1%). Visual impairment was associated with a 3.36-fold [95% confidence interval (CI) 1.17-9.65] higher DCGF risk, however, hearing [2.77 (95% CI 0.78-9.82)], physical [0.67 (95% CI 0.08-3.35)] and walking [0.50 (95% CI 0.06-3.89)] impairments were not. Walking impairment was associated with a 3.13-fold (95% CI 1.32-7.48) higher mortality risk, however, visual [1.20 (95% CI 0.48-2.98)], hearing [1.01 (95% CI 0.29-3.47)] and physical [1.16 (95% CI 0.34-3.94)] impairments were not. CONCLUSIONS: Impairments are common among KT recipients, yet only visual impairment and walking impairment are associated with adverse post-KT outcomes. Referring nephrologists and KT centers should identify recipients with visual and walking impairments who might benefit from targeted interventions pre-KT, additional supportive care and close post-KT monitoring.

Functional independence, access to kidney transplantation and waitlist mortality.

BACKGROUND: Approximately half of the patients who progress to end-stage kidney disease (ESKD) and undergo dialysis develop difficulties carrying out essential self-care activities, leading to institutionalization and mortality. It is unclear what percentage of kidney transplant (KT) candidates, a group of ESKD patients selected to be healthy enough to withstand transplantation, are functionally independent and whether independence is associated with better access to KT and reduced waitlist mortality. METHODS: We studied a prospective cohort of 3168 ESKD participants (January 2009 to June 2018) who self-reported functional independence in more basic self-care Activities of Daily Living (ADL) (needing help with eating, dressing, walking, grooming, toileting and bathing) and more complex instrumental ADL (IADL) (needing help using a phone, shopping, cooking, housework, washing, using transportation, managing medications and managing money). We estimated adjusted associations between functional independence (separately) and listing (Cox), waitlist mortality (competing risks) and transplant rates (Poisson). RESULTS: At KT evaluation, 92.4% were independent in ADLs, but only 68.5% were independent in IADLs. Functionally independent participants had a higher chance of listing for KT [ADL: adjusted hazard ratio (aHR) = 1.55, 95% confidence interval (CI) 1.30-1.87; IADL: aHR = 1.39, 95% CI 1.26-1.52]. Among KT candidates, ADL independence was associated with lower waitlist mortality risk [adjusted subdistribution HR (aSHR) = 0.66, 95% CI 0.44-0.98] and higher rate of KT [adjusted incidence rate ratio (aIRR) = 1.58, 95% CI 1.12-2.22]; the same was not observed for IADL independence (aSHR = 0.86, 95% CI 0.65-1.12; aIRR = 1.01, 95% CI 0.97-1.19). CONCLUSIONS: Functional independence in more basic self-care ADL was associated with better KT access and lower waitlist mortality. Nephrologists, geriatricians and transplant surgeons should screen KT candidates for ADLs, and identify interventions to promote independence and improve waitlist outcomes.

Projected 20- and 30-Year Outcomes for Pediatric Liver Transplant Recipients in the United States.

BACKGROUND: Observed long-term outcomes no longer reflect the survival trajectory facing pediatric liver transplant (LT) recipients today. We aimed to use national registry data and parametric models to project 20- and 30-year post-transplant outcomes for recently transplanted pediatric LT recipients. METHODS: We conducted a retrospective cohort study of 13,442 first-time pediatric (age <18) LT recipients using 1987 to 2018 Scientific Registry of Transplant Recipients data. We validated the proposed method (ie, to project long-term patient and graft survival using parametric survival models and short-term data) in 2 historic cohorts (1987-1996 and 1997-2006) and estimated long-term projections among patients transplanted between 2007 and 2018. Projections were stratified by raft type, recipient age, and indication for transplant. RESULTS: Parsimonious parametric models with Weibull distribution can be applied to post-transplant data and used to project long-term outcomes for pediatric LT recipients beyond observed data. Projected 20-year patient survival for pediatric LT recipients transplanted in 2007 to 2018 was 84.0% (95% confidence interval 81.5-85.8), compared to observed 20-year survival of 72.8% and 63.6% among those transplanted in 1997 to 2006 and 1987 to 1996, respectively. Projected 30-year survival for pediatric LT recipients in 2007 to 2018 was 80.1% (75.2-82.7), compared to projected 30-year survival of 68.6% (66.1-70.9) in the 1997 to 2006 cohort and observed 30-year survival of 57.5% in the 1987 to 1996 cohort. Twenty- and 30-year patient and graft survival varied slightly by recipient age, graft type, and indication for transplant. CONCLUSIONS: Projected long-term outcomes for recently transplanted pediatric LT recipients are excellent, reflective of substantial improvements in medical care, and informative for physician-patient education and decision making in the current era.

Interventions Made to Preserve Cognitive Function Trial (IMPCT) study protocol: a multi-dialysis center 2x2 factorial randomized controlled trial of intradialytic cognitive and exercise training to preserve cognitive function.

BACKGROUND: Kidney disease and dialysis significantly impact cognitive function across the age spectrum. Cognitive training (CT) and/or exercise training (ET) are promising approaches to preserve cognitive function among community-dwelling older adults, but have not been tested for cognition preservation in hemodialysis patients of all ages. In this manuscript, we summarize the protocol for the Interventions Made to Preserve Cognitive Function Trial (IMPCT). METHODS: We will perform a 2 × 2 factorial randomized controlled trial (RCT) of eligible adult (≥18 years) hemodialysis initiates (n = 200) to test whether intradialytic CT (brain games on a tablet PC), ET (foot peddlers) and combined CT + ET while undergoing hemodialysis preserves executive function compared to standard of care (SC). Participants will engage in the interventions to which they are randomized for 6 months. The primary objective is to compare, among interventions, the 3-month change in executive function measured using the Trail Making Test A (TMTA) and B (TMTB); specifically, executive function is calculated as TMTB-TMTA to account for psychomotor speed. This primary outcome was selected based on findings from our pilot study. The secondary objectives are to compare the risk of secondary cognitive outcomes, ESKD-specific clinical outcomes, and patient-centered outcomes at 3-months and 6-months. All data collection and interventions are conducted in the dialysis center. DISCUSSION: We hypothesize that receiving intradialytic CT or ET will better preserve executive function than SC but receiving combined CT + ET, will be the most effective intervention. The current trial will be an important step in understanding how intradialytic interventions might preserve cognitive health. TRIAL REGISTRATION: Clinicaltrials.Gov (Date: 8/6/18): # NCT03616535 . Protocol Version: 10 (April 2020). FUNDING: NIDDK R01DK114074.

Frailty and Changes in Cognitive Function after Kidney Transplantation.

BACKGROUND: Restoration of kidney function after kidney transplant generally improves cognitive function. It is unclear whether frail recipients, with higher susceptibility to surgical stressors, achieve such post-transplant cognitive improvements or whether they experience subsequent cognitive decline as they age with a functioning graft. METHODS: In this two-center cohort study, we assessed pretransplant frailty (Fried physical frailty phenotype) and cognitive function (Modified Mini-Mental State Examination) in adult kidney transplant recipients. To investigate potential short- and medium-term effects of frailty on post-transplant cognitive trajectories, we measured cognitive function up to 4 years post-transplant. Using an adjusted mixed effects model with a random slope (time) and intercept (person), we characterized post-transplant cognitive trajectories by pretransplant frailty, accounting for nonlinear trajectories. RESULTS: Of 665 recipients (mean age 52.0 years) followed for a median of 1.5 years, 15.0% were frail. After adjustment, pretransplant cognitive scores were significantly lower among frail patients compared with nonfrail patients (89.0 versus 90.8 points). By 3 months post-transplant, cognitive performance improved for both frail (slope =0.22 points per week) and nonfrail (slope =0.14 points per week) recipients. Between 1 and 4 years post-transplant, improvements plateaued among nonfrail recipients (slope =0.005 points per week), whereas cognitive function declined among frail recipients (slope =-0.04 points per week). At 4 years post-transplant, cognitive scores were 5.8 points lower for frail recipients compared with nonfrail recipients. CONCLUSIONS: On average, both frail and nonfrail recipients experience short-term cognitive improvement post-transplant. However, frailty is associated with medium-term cognitive decline post-transplant. Interventions to prevent cognitive decline among frail recipients should be identified.

Comorbidity, Frailty, and Waitlist Mortality among Kidney Transplant Candidates of All Ages.

BACKGROUND: Kidney transplantation (KT) candidates often present with multiple comorbidities. These patients also have a substantial burden of frailty, which is also associated with increased mortality. However, it is unknown if frailty is merely a surrogate for comorbidity, itself an independent domain of risk, or if frailty and comorbidity have differential effects. Better understanding the interplay between these 2 constructs will improve clinical decision making in KT candidates. OBJECTIVE: To test whether comorbidity is equally associated with waitlist mortality among frail and nonfrail KT candidates and to test whether measuring both comorbidity burden and frailty improves mortality risk prediction. METHODS: We studied 2,086 candidates on the KT waitlist (November 2009 - October 2017) in a multicenter cohort study, in whom frailty and comorbidity were measured at evaluation. We quantified the association between Charlson comorbidity index (CCI) adapted for end-stage renal disease and waitlist mortality using an adjusted Cox proportional hazards model and tested whether this association differed between frail and nonfrail candidates. RESULTS: At evaluation, 18.1% of KT candidates were frail and 51% had a high comorbidity burden (CCI score ≥2). Candidates with a high comorbidity burden were at 1.38-fold (95% CI 1.01-1.89) increased risk of waitlist mortality. However, this association differed by frailty status (p for interaction = 0.01): among nonfrail candidates, a high comorbidity burden was associated with a 1.66-fold (95% CI 1.17-2.35) increased mortality risk; among frail candidates, here was no statistically significant association (HR 0.75, 95% CI 0.44-1.29). Adding this interaction between comorbidity and frailty to a mortality risk estimation model significantly improved prediction, increasing the c-statistic from 0.640 to 0.656 (p < 0.001). CONCLUSIONS: Nonfrail candidates with a high comorbidity burden at KT evaluation have an increased risk of waitlist mortality. Importantly, comorbidity is less of a concern in already high-risk patients who are frail.