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BACKGROUND: Motility disorders are frequently encountered in gastroenterology (GI) practice, yet a national structured training curriculum for GI fellows in motility disorders is lacking. Since GI fellowships vary considerably in opportunities for specialized esophageal motility (EM) training, novel educational technology may be leveraged to provide standardized EM curriculum to train GI fellows in esophageal manometry. METHODS: GI fellows participated in an online EM learning program at a single academic center from 2017 to 2022. Fellows answered case-based questions and were provided with evidence-based, corrective feedback related to core EM learning objectives. The primary outcome was change in knowledge and comfort in interpretation and clinical application of EM studies. RESULTS: Sixty-nine fellows actively participated in the online EM curriculum. 65 fellows completed a pre-curriculum test, and 54 fellows completed a post-curriculum test. There was a cumulative improvement between pre-curriculum test and post-curriculum test scores from 70 to 87%, respectively (p < 0.001). Fellows had a mean improvement of 19% in questions as they progressed through the curriculum. Prior to enrolling in the EM course, 26% of fellows felt comfortable in interpreting EM studies compared to 54% of fellows after completion of the program (p < 0.001). CONCLUSION: An online, technology-based curriculum was effective in educating GI fellows on core competencies of EM. Fellows demonstrated improvement in proficiency of clinically important EM studies and increased comfort in interpreting EM studies. Further studies are needed to evaluate the use of technology-based learning to widely disseminate a structured training curriculum in EM, particularly in training programs without a motility presence.
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Currículo , Transtornos da Motilidade Esofágica , Bolsas de Estudo , Gastroenterologia , Gastroenterologia/educação , Humanos , Transtornos da Motilidade Esofágica/diagnóstico , Transtornos da Motilidade Esofágica/fisiopatologia , Transtornos da Motilidade Esofágica/terapia , Competência Clínica , Educação de Pós-Graduação em Medicina/métodos , Manometria , Educação a Distância/métodosRESUMO
BACKGROUND AND AIMS: Autoimmune hepatitis (AIH) disproportionately affects young women, which may have implications in pregnancy. However, data on pregnancy outcomes in women with AIH are limited. APPROACH AND RESULTS: Using weighted discharge data from the United States National Inpatient Sample from 2012 to 2016, we evaluated pregnancies after 20 weeks gestation and compared outcomes in AIH to other chronic liver diseases (CLD) or no CLD in pregnancy. The association of AIH with maternal and perinatal outcomes was assessed by logistic regression. Among 18,595,345 pregnancies, 935 (<0.001%) had AIH (60 with cirrhosis) and 120,100 (0.006%) had other CLD (845 with cirrhosis). Temporal trends in pregnancies with AIH remained stable from 2008 to 2016 with 1.4-6.8/100,000 pregnancies per year (p = 0.25). On adjusted analysis, the odds of gestational diabetes (GDM) and hypertensive complications (pre-eclampsia, eclampsia, or hemolysis, elevated liver enzymes, low platelets) were significantly higher in AIH compared to other CLD (GDM: OR 2.2, 95% CI: 1.5-3.9, p < 0.001; hypertensive complications: OR: 1.8, 95% CI: 1.0-3.2, p = 0.05) and also compared to no CLD in pregnancy (GDM: OR: 2.4, 95% CI: 1.6-3.6, p < 0.001; hypertensive complications: OR: 2.4, 95% CI: 1.3-4.1, p = 0.003). AIH was also associated with preterm births when compared with women without CLD (OR: 2.0, 95% CI: 1.2-3.5, p = 0.01). AIH was not associated with postpartum hemorrhage, maternal, or perinatal death. CONCLUSIONS: Rates of pregnancy in women with AIH have remained stable in recent years, although AIH is associated with notable maternal and perinatal risks, such as GDM, hypertensive complications, and preterm birth. Whether these risks are influenced by steroid use and/or AIH disease activity warrants evaluation. These data support a low risk of postpartum hemorrhage and favorable survival of mothers and infants.
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Diabetes Gestacional/epidemiologia , Hepatite Autoimune/complicações , Pré-Eclâmpsia/epidemiologia , Nascimento Prematuro/epidemiologia , Adulto , Diabetes Gestacional/imunologia , Feminino , Hepatite Autoimune/imunologia , Humanos , Recém-Nascido , Pré-Eclâmpsia/imunologia , Gravidez , Nascimento Prematuro/imunologia , Estudos Retrospectivos , Estados Unidos/epidemiologiaRESUMO
INTRODUCTION: The coronavirus disease 19 (COVID-19) pandemic has disrupted healthcare delivery including elective endoscopy. We aimed to determine the prevalence of endoscopy cancellations in the COVID-19 era and identify patient characteristics associated with cancellation due to the pandemic. METHODS: Medical charts were reviewed for adults who cancelled an outpatient endoscopic procedure from 5/2020 to 8/2020. The association of patient characteristics with cancellation of endoscopy due to COVID-19 was assessed using logistic regression. RESULTS: There were 652 endoscopy cancelations with 211 (32%) due to COVID-19, 384 (59%) due to non-COVID reasons, and 57 (9%) undetermined. Among COVID-19 related cancellations, 75 (36%) were COVID-19 testing logistics related, 121 (57%) were COVID-19 fear related, and 15 (7%) were other. On adjusted analysis, the odds of cancellation due to COVID-19 was significantly higher for black patients (OR 2.04, 95% CI 1.07-3.88, p = 0.03), while patients undergoing EGD (OR 0.56, 95% CI 0.31-0.99, p = 0.05) or advanced endoscopy (OR 0.18, 95% CI 0.07-0.49, p = 0.001) had lower odds of cancellation. The odds of cancelling due to COVID-19 testing logistics was significantly higher among black patients (OR 3.12, 95% CI 1.03-9.46, p = 0.05) and patients with Medi-Cal insurance (OR 2.89, 95% CI 1.21-6.89, p = 0.02). CONCLUSION: Black race is associated with an increased risk of COVID-19 related cancellation. Specifically, black patients and those with Medi-Cal are at increased risk of cancellation related to logistics of obtaining pre-endoscopy COVID-19 testing. Racial and socioeconomic disparities in access to endoscopy may be further amplified by the COVID-19 pandemic and warrant further study.
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COVID-19 , Adulto , Humanos , COVID-19/epidemiologia , Pandemias/prevenção & controle , Teste para COVID-19 , Grupos Raciais , EndoscopiaRESUMO
BACKGROUND: Patients with end-stage liver disease awaiting liver transplantation (LT) are seriously ill and experience fluctuating periods of clinical decompensation. Discussion of a patient's advance care planning (ACP) wishes early in their dynamic disease course is critical to providing value-aligned care while awaiting LT. We aimed to evaluate current ACP documentation and assess readiness to engage in ACP in this population. METHODS: We conducted a retrospective study of adults undergoing LT evaluation from January 2017 to June 2017 and assessed characteristics associated with documentation using logistic regression. We then administered a survey to LT candidates from March 2018 to May 2018 to determine self-reported readiness to engage in ACP (range 1 = not at all ready to 5 = very ready). RESULTS: Among 170 LT candidates, median (interquartile range) age was 58 (53-65), 65% were men, MELDNa was 15 (11-21), and Child-Pugh A/B/C were 33/38/29%. Nine percent reported completing ACP prior to LT evaluation, but 0% had legal ACP forms or end-of-life wishes documented in the medical record. A durable power of attorney (DPOA) was discussed with 10%. In univariable analysis, white race (OR 4.16, p = 0.03) and female sex (OR 3.06, p = 0.04) were associated with ACP documentation, but Child-Pugh score and MELDNa were not. Of the 41 LT candidates who completed the ACP survey, 93% were ready to appoint a DPOA and 85% were ready to discuss end-of-life care. CONCLUSION: There is a paucity of ACP documentation and identification of DPOA among LT candidates, despite patients reporting readiness to complete ACP and appoint a DPOA. These results reveal an opportunity for tools to facilitate discussions around ACP between clinicians, patients, and their caregivers.
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Planejamento Antecipado de Cuidados , Doença Hepática Terminal/cirurgia , Transplante de Fígado , Aceitação pelo Paciente de Cuidados de Saúde , Assistência Terminal , Transplantados/psicologia , Diretivas Antecipadas , Idoso , Documentação , Doença Hepática Terminal/diagnóstico , Doença Hepática Terminal/mortalidade , Feminino , Conhecimentos, Atitudes e Prática em Saúde , Humanos , Transplante de Fígado/efeitos adversos , Transplante de Fígado/mortalidade , Masculino , Pessoa de Meia-Idade , Procurador , Estudos Retrospectivos , AutorrelatoRESUMO
The Liver Frailty Index (LFI), composed of 3 performance-based tests (grip strength, chair stands, and balance), is a tool specifically developed in patients with cirrhosis to objectively measure physical function, a critical determinant of health outcomes. We aimed to (1) determine the range of LFI scores in adults with chronic liver disease but without cirrhosis, (2) determine the range of LFI scores in adults without known liver disease, and (3) evaluate reproducibility of the LFI in adults with cirrhosis listed for liver transplantation. Intraclass correlation coefficient (ICC) assessed interrater reliability of the LFI. Included were 91 adults with chronic liver disease, 109 adults without known liver disease, and 166 adults with cirrhosis with median Model for End-Stage Liver Disease-sodium of 16. Median (interquartile range) LFI was 3.6 (3.1-4.1) in adults with cirrhosis, 3.1 (2.5-3.7) in adults with chronic liver disease but not cirrhosis, and 2.7 (2.2-3.2) in adults without liver disease (P < 0.001). Using established LFI cutoffs for robust, prefrail, and frail categories, adults with cirrhosis or chronic liver disease were less likely to be robust (29% versus 53% versus 77%) and more likely to be prefrail (57% versus 42% versus 22%) or frail (14% versus 5% versus 1%) when compared with adults without liver disease (P < 0.001). The LFI had excellent reliability with ICC of 0.93 (95% confidence interval, 0.91-0.95). In conclusion, the LFI has external validity in noncirrhotic populations and is highly reproducible among different raters. This objective assessment tool can be implemented in outpatient clinical practice or research to operationalize the concept of physical frailty.
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Doença Hepática Terminal/fisiopatologia , Fragilidade/diagnóstico , Cirrose Hepática/fisiopatologia , Transplante de Fígado , Fígado/fisiopatologia , Cuidados Pré-Operatórios/métodos , Adulto , Idoso , Tomada de Decisão Clínica/métodos , Estudos de Coortes , Doença Hepática Terminal/diagnóstico , Doença Hepática Terminal/mortalidade , Doença Hepática Terminal/cirurgia , Estudos de Viabilidade , Feminino , Fragilidade/fisiopatologia , Humanos , Cirrose Hepática/diagnóstico , Cirrose Hepática/mortalidade , Cirrose Hepática/cirurgia , Masculino , Pessoa de Meia-Idade , Seleção de Pacientes , Prognóstico , Reprodutibilidade dos Testes , Índice de Gravidade de Doença , Listas de Espera/mortalidadeAssuntos
Adenocarcinoma/tratamento farmacológico , Catéteres/efeitos adversos , Duodenopatias/etiologia , Hemorragia Gastrointestinal/etiologia , Neoplasias Hepáticas/tratamento farmacológico , Neoplasias do Colo Sigmoide/patologia , Adenocarcinoma/secundário , Angiografia , Antimetabólitos Antineoplásicos/administração & dosagem , Duodenopatias/diagnóstico por imagem , Endoscopia Gastrointestinal , Floxuridina/administração & dosagem , Hemorragia Gastrointestinal/diagnóstico por imagem , Humanos , Bombas de Infusão Implantáveis , Neoplasias Hepáticas/secundário , Masculino , Pessoa de Meia-IdadeRESUMO
Sarcopenia is associated with increased wait-list mortality, but a standard definition is lacking. In this retrospective study, we sought to determine the optimal definition of sarcopenia in end-stage liver disease (ESLD) patients awaiting liver transplantation (LT). Included were 396 patients newly listed for LT in 2012 at 5 North American transplant centers. All computed tomography scans were read by 2 individuals with interobserver correlation of 98%. Using image analysis software, the total cross-sectional area (cm2 ) of abdominal skeletal muscle at the third lumbar vertebra was measured. The skeletal muscle index (SMI), which normalizes muscle area to patient height, was then calculated. The primary outcome was wait-list mortality, defined as death on the waiting list or removal from the waiting list for reasons of clinical deterioration. Sex-specific potential cutoff values to define sarcopenia were determined with a grid search guided by log-rank test statistics. Optimal search methods identified potential cutoffs to detect survival differences between groups. The overall median SMI was 47.6 cm2 /m2 : 50.0 in men and 42.0 in women. At a median of 8.8 months follow-up, mortality was 25% in men and 36% in women. Patients who died had lower SMI than those who survived (45.6 versus 48.5 cm2 /m2 ; P < 0.001), and SMI was associated with wait-list mortality (hazard ratio, 0.95; P < 0.001). Optimal search method yielded SMI cutoffs of 50 cm2 /m2 for men and 39 cm2 /m2 for women; these cutoff values best combined statistical significance with a sufficient number of events to detect survival differences between groups. In conclusion, we recommend that an SMI < 50 cm2 /m2 for men and < 39 cm2 /m2 for women be used to define sarcopenia in patients with ESLD awaiting LT. Liver Transplantation 23 625-633 2017 AASLD.
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Doença Hepática Terminal/complicações , Sarcopenia/diagnóstico , Feminino , Humanos , Masculino , Pessoa de Meia-Idade , Estudos Retrospectivos , Sarcopenia/etnologia , Sarcopenia/mortalidade , Fatores Sexuais , Estados Unidos/epidemiologiaRESUMO
The emerging epidemic of older patients with cirrhosis has led to a sharp increase in the number of ≥65 year olds considering liver transplantation (LT). However, clinicians lack objective measures to risk stratify older patients. We aimed to determine whether the short physical performance battery (SPPB), a well-validated geriatric measure of physical function, has greater prognostic value in older versus younger LT candidates. Adult outpatients listed for LT with laboratory Model for End-Stage Liver Disease score ≥ 12 underwent physical function testing using the SPPB, consisting of gait speed, chair stands, and balance. Patients were categorized by age ("younger," < 65 years; "older," ≥ 65 years) and SPPB ("impaired," ≤ 9; "robust," > 9). Competing risks models associated age and SPPB with wait-list death/delisting. Of 463 LT candidates, 21% were ≥ 65 years and 18% died or were delisted. Older patients had slower gait (1.1 versus 1.3 m/seconds; P < 0.001), a trend of slower chair stands (12.8 versus 11.8 seconds; P = 0.06), and a smaller proportion able to complete all balance tests (65% versus 78%; P = 0.01); SPPB was lower in older versus younger patients (10 versus 11; P = 0.01). When compared to younger robust patients as a reference group, younger impaired patients (hazard ratio [HR], 1.77; P = 0.03) and older impaired patients (HR, 2.70; P = 0.003) had significantly higher risk of wait-list mortality, but there was no difference in risk for older robust patients (HR 1.38; P = 0.35) [test of equality, P = 0.01]. After adjustment for Model for End-Stage Liver Disease-sodium (MELD-Na) score, only older impaired patients had an increased risk of wait-list mortality compared to younger robust patients (HR, 2.36; P = 0.01; test of equality P = 0.05). In conclusion, functional impairment, as assessed by the SPPB, predicts death/delisting for LT candidates ≥65 years independent of MELD-Na. Further research into activity-based interventions to reduce adverse transplant outcomes in this population is warranted.
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Avaliação Geriátrica , Transplante de Fígado , Seleção de Pacientes , Listas de Espera/mortalidade , Idoso , Feminino , Humanos , Masculino , Pessoa de Meia-Idade , Estudos Prospectivos , Estados Unidos/epidemiologiaRESUMO
Polycystic ovary syndrome (PCOS) occurs in approximately 10% of all reproductive-age women, with over 50% of these patients having imaging-confirmed nonalcoholic fatty liver disease (NAFLD). Whether PCOS increases the risk for more clinically relevant disease, such as nonalcoholic steatohepatitis (NASH), is unclear. Such findings are relevant to prognosticating risk of progressive liver disease in the growing population of young adults with NAFLD. Using weighted discharge data from the United States National Inpatient Sample from 2016 to 2018, we evaluated the association of PCOS with the presence of NASH among reproductive-age women with NAFLD. The association of PCOS with NASH was assessed by logistic regression, adjusting for demographic and comprehensive metabolic comorbidities. Other causes of hepatic steatosis and chronic liver diseases were excluded. Our analysis included 189,440 reproductive-age women with NAFLD, 9415 of whom had PCOS. Of those with PCOS, 1390 (15%) had a distinct code for NASH. Women with PCOS were younger (median age, 33 vs. 40 years; p < 0.001) and more likely to have diabetes (37.0% vs. 34.0%), obesity (83.0% vs. 58.0%), dyslipidemia (26.0% vs. 21.0%), and hypertension (38.0% vs. 35.0%) (all p ≤ 0.01). On adjusted analysis accounting for these metabolic comorbidities, PCOS remained independently associated with an increased prevalence of NASH (adjusted odds ratio, 1.22; 95% confidence interval, 1.05-1.42; p = 0.008). Conclusions: Among reproductive-age women with NAFLD, metabolic risk factors were more common in those with PCOS. Despite adjustment for these metabolic comorbidities, PCOS remained associated with a 22% higher odds of having NASH. These findings support efforts to increase NAFLD screening in young women with PCOS and highlight the potential "head start" in progressive liver disease among young women with PCOS.
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Dislipidemias , Hepatopatia Gordurosa não Alcoólica , Síndrome do Ovário Policístico , Adulto , Dislipidemias/complicações , Feminino , Humanos , Hepatopatia Gordurosa não Alcoólica/diagnóstico , Obesidade/epidemiologia , Síndrome do Ovário Policístico/complicações , Fatores de Risco , Adulto JovemRESUMO
OBJECTIVES: Frailty is prevalent in patients with cirrhosis and is hypothesized to result in part from sarcopenia, but the precise contribution of sarcopenia to frailty in this population is poorly understood. METHODS: Included were patients with cirrhosis from 2011 to 2014 who had an ambulatory frailty assessment and abdominal computed tomography scan within 3 months. Logistic regression assessed the associations between frailty (=Liver Frailty Index ≥4.5), and sarcopenia (=skeletal muscle index of <39 cm/m for women and <50 cm/m for men). RESULTS: Two hundred ninety-one participants were included: 33% were female. The median (interquartile range) Liver Frailty Index was 3.7 (3.3-4.2); 19% were frail. The median (interquartile range) skeletal muscle index was 49 cm/m (31-69); 36% had sarcopenia. Among the 54 frail participants, 48% had sarcopenia. In univariable logistic regression, sarcopenia was associated with a 1.86× increased odds of being frail (95% confidence interval [CI], 1.02-3.38). After adjusting for sex, etiology, hepatocellular carcinoma, MELDNa, ascites, encephalopathy, and hypertension, sarcopenia was associated with a 2.38× increased odds of being frail (95% CI, 1.17-4.85). After stratifying by sex and adjusting for MELDNa, sarcopenia among males was associated with a significantly increased odds of frailty (odds ratio 2.81, 95% CI, 1.19-6.67), whereas sarcopenia among females was not (odds ratio 1.38; 95% CI, 0.45-4.25). DISCUSSION: In patients with cirrhosis, sarcopenia was associated with a nearly 2-fold increased odds of being frail. Two-thirds of frail men displayed sarcopenia compared with only one-quarter of frail women. Contributors to the frail phenotype may differ by sex and support the need for sex-specific strategies to reduce frailty in this population.
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Fragilidade/epidemiologia , Cirrose Hepática/complicações , Sarcopenia/epidemiologia , Idoso , Feminino , Fragilidade/diagnóstico , Fragilidade/etiologia , Fragilidade/prevenção & controle , Humanos , Masculino , Pessoa de Meia-Idade , Razão de Chances , Prevalência , Estudos Prospectivos , Sarcopenia/diagnóstico , Sarcopenia/etiologia , Fatores SexuaisRESUMO
BACKGROUND: Sarcopenia, characterized by low muscle mass, associates with mortality in patients with cirrhosis. Skeletal muscle area in a single computed tomography image at the level of the third lumbar vertebrate (L3) is a valid representative of whole body muscle mass. Controversy remains regarding applicability of psoas muscle to identify patients at greater risk of mortality. We aimed to determine psoas muscle index (PMI) association with skeletal muscle index (SMI) and to evaluate the capacity of PMI to predict liver transplant waitlist mortality. METHODS: We evaluated listed adult patients with cirrhosis from 2012 to 2013 at four North American liver transplant centres. From L3 computed tomography images within 3 months of listing, we determined SMI and PMI expressed by cm2 /m2 . Low SMI was defined as SMI <39 cm2 /m2 in women and <50 cm2 /m2 in men as published by us earlier. Cut-offs for PMI to predict mortality were established using a receiver-operating characteristic analysis. Mortality predictors were determined using competing-risk analysis with reported results as subdistribution hazard ratios (sHRs). RESULTS: Of 353 waitlist candidates, 68% were men, mean age 56 ± 9 years, and Model for End-stage Liver Disease of 16 ± 8 points. Low SMI was present more frequently in men than women (51 vs. 36%, P = 0.02). Moderately strong correlation between SMI and PMI was observed (r > 0.7, P < 0.001). Low PMI (males < 5.1 cm2 /m2 ; females < 4.3 cm2 /m2 ) yielded poor and moderate concordance with low SMI in men and women, respectively (Kappa coefficient 0.31 and 0.63). SMI (39 ± 9 vs. 43 ± 7 cm2 /m2 ; P = 0.009) and PMI (4.4 ± 1.3 vs. 5.2 ± 1.1 cm2 /m2 ; P = 0.001) were lower in women who died and/or were delisted (compared with non-deceased patients) whereas men who died and/or were delisted had only lower SMI (47 ± 7 vs. 51 ± 9 cm2 /m2 ; P = 0.003), but not PMI compared with non-deceased patients. In women, both SMI (sHR 0.94, P = 0.048) and PMI (sHR 0.58, P = 0.002) were predictors of mortality, while in men, SMI was significant (sHR 0.95, P = 0.001) and PMI showed a trend to be (sHR 0.85, P = 0.09) associated with mortality. Overall, 104 patients (29%) were misclassified between SMI and PMI categories. Using PMI cut-offs, 66% and 28% of low SMI men and women, who have a higher risk of mortality, were incorrectly classified as low risk. CONCLUSIONS: Skeletal muscle index is a more complete and robust measurement than PMI, especially in men with cirrhosis. Low PMI identifies an incomplete subset of patients at increased risk of mortality indicated by low SMI. Given the poor performance of PMI, SMI should not be substituted by PMI.
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Cirrose Hepática/mortalidade , Músculos Psoas/patologia , Músculos Psoas/fisiopatologia , Idoso , Biomarcadores , Comorbidade , Feminino , Humanos , Estimativa de Kaplan-Meier , Cirrose Hepática/etiologia , Cirrose Hepática/terapia , Transplante de Fígado , Masculino , Pessoa de Meia-Idade , Tamanho do Órgão , Prognóstico , Músculos Psoas/diagnóstico por imagem , Medição de Risco , Fatores de Risco , Fatores Sexuais , Tomografia Computadorizada por Raios XRESUMO
BACKGROUND: Sarcopenia and functional impairment are common and lethal extrahepatic manifestations of cirrhosis. We aimed to determine the association between computed tomography (CT)-based measures of muscle mass and quality (sarcopenia) and performance-based measures of muscle function. METHODS: Adults listed for liver transplant underwent testing of muscle function (grip strength, Short Physical Performance Battery [SPPB]) within 3 months of abdominal CT. Muscle mass (cm/m) = total cross-sectional area of psoas, paraspinal, and abdominal wall muscles at L3 on CT, normalized for height. Muscle quality = mean Hounsfield units for total skeletal muscle area at L3. RESULTS: Among 292 candidates, median grip strength was 31 kg, SPPB score was 11, muscle mass was 49 cm/m, and muscle quality was 35 Hounsfield units. Grip strength weakly correlated with muscle mass (ρ = 0.26, P < 0.001) and quality (ρ = 0.27, P < 0.001) in men, and muscle quality (ρ = 0.23, P = 0.02), but not muscle mass, in women. Short Physical Performance Battery correlated weakly with muscle quality in men (ρ = 0.38, P < 0.001) and women (ρ = 0.25, P = 0.02), however, did not correlate with muscle mass in men or women. After adjustment for sex, model for end-stage liver disease (MELD)-Na, hepatocellular carcinoma, and body mass index, grip strength (hazard ratio [HR], 0.74; 95% confidence interval [95% CI], 0.59-0.92; P = 0.008), SPPB (HR, 0.89; 95% CI, 0.82-0.97; P = 0.01), and muscle quality (HR, 0.77; 95% CI, 0.63-0.95; P = 0.02) were associated with waitlist mortality, but muscle mass was not (HR, 0.91; 95% CI, 0.75-1.11; P = 0.35). CONCLUSIONS: Performance-based tests of muscle function are only modestly associated with CT-based muscle measures. Given that they predict waitlist mortality and can be conducted quickly and economically, tests of muscle function may have greater clinical utility than CT-based measures of sarcopenia.
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Hepatopatias/complicações , Transplante de Fígado , Força Muscular , Músculo Esquelético/diagnóstico por imagem , Músculo Esquelético/fisiopatologia , Sarcopenia/diagnóstico , Tomografia Computadorizada por Raios X , Listas de Espera , Idoso , Distribuição de Qui-Quadrado , Feminino , Nível de Saúde , Humanos , Hepatopatias/diagnóstico , Hepatopatias/mortalidade , Hepatopatias/cirurgia , Masculino , Pessoa de Meia-Idade , Análise Multivariada , Razão de Chances , Tamanho do Órgão , Valor Preditivo dos Testes , Prognóstico , Modelos de Riscos Proporcionais , Reprodutibilidade dos Testes , Fatores de Risco , Sarcopenia/diagnóstico por imagem , Sarcopenia/etiologia , Sarcopenia/fisiopatologia , Fatores de Tempo , Listas de Espera/mortalidadeRESUMO
The suprachiasmatic nucleus (SCN) of the hypothalamus synchronizes circadian rhythms of cells and tissues throughout the body. In SCN neurons, rhythms of clock gene expression are suppressed by manipulations that hyperpolarize the plasma membrane or lower intracellular Ca(2+). However, whether clocks in other cells also depend on membrane potential and calcium is unknown. In this study, the authors investigate the effects of membrane potential and intracellular calcium on circadian rhythms in mouse primary fibroblasts. Rhythms of clock gene expression were monitored using a PER2::LUC knockin reporter. Rhythms were lost or delayed at lower (hyperpolarizing) K(+) concentrations. Bioluminescence imaging revealed that this loss of rhythmicity in cultures was due to loss of rhythmicity of single cells rather than loss of synchrony among cells. In lower Ca(2+) concentrations, rhythms were advanced or had shorter periods. Buffering intracellular Ca(2+) by the calcium chelator 1,2-Bis(2-aminophenoxy)ethane-N,N,N',N'-tetraacetic acid tetrakis acetoxymethyl ester (BAPTA-AM) or manipulation of inositol triphosphate (IP(3))-sensitive intracellular calcium stores by thapsigargin delayed rhythms. These results suggest that the circadian clock in fibroblasts, as in SCN neurons, is regulated by membrane potential and Ca(2+). Changes in intracellular Ca(2+) may mediate the effects of membrane potential observed in this study.
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Cálcio/metabolismo , Ritmo Circadiano , Fibroblastos/metabolismo , Espaço Intracelular/metabolismo , Potenciais da Membrana , Proteínas Circadianas Period/metabolismo , Animais , Células Cultivadas , Quelantes/farmacologia , Ritmo Circadiano/efeitos dos fármacos , Ritmo Circadiano/genética , Ácido Egtázico/análogos & derivados , Ácido Egtázico/farmacologia , Fibroblastos/citologia , Fibroblastos/efeitos dos fármacos , Expressão Gênica/genética , Camundongos , Camundongos Transgênicos , Potássio/metabolismo , Núcleo Supraquiasmático/fisiologiaRESUMO
Biological oscillators naturally exhibit stochastic fluctuations in period and amplitude due to the random nature of molecular reactions. Accurately measuring the precision of noisy oscillators and the heterogeneity in period and strength of rhythmicity across a population of cells requires single-cell recordings of sufficient length to fully represent the variability of oscillations. We found persistent, independent circadian oscillations of clock gene expression in 6-week-long bioluminescence recordings of 80 primary fibroblast cells dissociated from PER2::LUC mice and kept in vitro for 6 months. Due to the stochastic nature of rhythmicity, the proportion of cells appearing rhythmic increases with the length of interval examined, with 100% of cells found to be rhythmic when using 3-week windows. Mean period and amplitude are remarkably stable throughout the 6-week recordings, with precision improving over time. For individual cells, precision of period and amplitude are correlated with cell size and rhythm amplitude, but not with period, and period exhibits much less cycle-to-cycle variability (CV 7.3%) than does amplitude (CV 37%). The time series are long enough to distinguish stochastic fluctuations within each cell from differences among cells, and we conclude that the cells do exhibit significant heterogeneity in period and strength of rhythmicity, which we measure using a novel statistical metric. Furthermore, stochastic modeling suggests that these single-cell clocks operate near a Hopf bifurcation, such that intrinsic noise enhances the oscillations by minimizing period variability and sustaining amplitude.