A landscape of driver mutations in melanoma.

Despite recent insights into melanoma genetics, systematic surveys for driver mutations are challenged by an abundance of passenger mutations caused by carcinogenic UV light exposure. We developed a permutation-based framework to address this challenge, employing mutation data from intronic sequences to control for passenger mutational load on a per gene basis. Analysis of large-scale melanoma exome data by this approach discovered six novel melanoma genes (PPP6C, RAC1, SNX31, TACC1, STK19, and ARID2), three of which-RAC1, PPP6C, and STK19-harbored recurrent and potentially targetable mutations. Integration with chromosomal copy number data contextualized the landscape of driver mutations, providing oncogenic insights in BRAF- and NRAS-driven melanoma as well as those without known NRAS/BRAF mutations. The landscape also clarified a mutational basis for RB and p53 pathway deregulation in this malignancy. Finally, the spectrum of driver mutations provided unequivocal genomic evidence for a direct mutagenic role of UV light in melanoma pathogenesis.

Experience-Dependent Coding of Time-Dependent Frequency Trajectories by Off Responses in Secondary Auditory Cortex.

Time-dependent frequency trajectories are an inherent feature of many behaviorally relevant sounds, such as species-specific vocalizations. Dynamic frequency trajectories, even in short sounds, often convey meaningful information, which may be used to differentiate sound categories. However, it is not clear what and where neural responses in the auditory cortical pathway are critical for conveying information about behaviorally relevant frequency trajectories, and how these responses change with experience. Here, we uncover tuning to subtle variations in frequency trajectories in auditory cortex of female mice. We found that auditory cortical responses could be modulated by variations in a pure tone trajectory as small as 1/24th of an octave, comparable to what has been reported in primates. In particular, late spiking after the end of a sound stimulus was more often sensitive to the sound's subtle frequency variation compared with spiking during the sound. Such "Off" responses in the adult A2, but not those in core auditory cortex, were plastic in a way that may enhance the representation of a newly acquired, behaviorally relevant sound category. We illustrate this with the maternal mouse paradigm for natural vocalization learning. By using an ethologically inspired paradigm to drive auditory responses in higher-order neurons, our results demonstrate that mouse auditory cortex can track fine frequency changes, which allows A2 Off responses in particular to better respond to pitch trajectories that distinguish behaviorally relevant, natural sound categories.SIGNIFICANCE STATEMENT A whistle's pitch conveys meaning to its listener, as when dogs learn that distinct pitch trajectories whistled by their owner differentiate specific commands. Many species use pitch trajectories in their own vocalizations to distinguish sound categories, such as in human languages, such as Mandarin. How and where auditory neural activity encodes these pitch trajectories as their meaning is learned but not well understood, especially for short-duration sounds. We studied this in mice, where infants use ultrasonic whistles to communicate to adults. We found that late neural firing after a sound ends can be tuned to how the pitch changes in time, and that this response in a secondary auditory cortical field changes with experience to acquire a pitch change's meaning.

Becoming a better parent: Mice learn sounds that improve a stereotyped maternal behavior.

While mothering is often instinctive and stereotyped in species-specific ways, evolution can favor genetically "open" behavior programs that allow experience to shape infant care. Among experience-dependent maternal behavioral mechanisms, sensory learning about infants has been hard to separate from motivational changes arising from sensitization with infants. We developed a paradigm in which sensory learning of an infant-associated cue improves a stereotypical maternal behavior in female mice. Mice instinctively employed a spatial memory-based strategy when engaged repetitively in a pup search and retrieval task. However, by playing a sound from a T-maze arm to signal where a pup will be delivered for retrieval, mice learned within 7 days and retained for at least 2 weeks the ability to use this specific cue to guide a more efficient search strategy. The motivation to retrieve pups also increased with learning on average, but their correlation did not explain performance at the trial level. Bilaterally silencing auditory cortical activity significantly impaired the utilization of new strategy without changing the motivation to retrieve pups. Finally, motherhood as compared to infant-care experience alone accelerated how quickly the new sensory-based strategy was acquired, suggesting a role for the maternal hormonal state. By rigorously establishing that newly formed sensory associations can improve the performance of a natural maternal behavior, this work facilitates future studies into the neurochemical and circuit mechanisms that mediate novel sensory learning in the maternal context, as well as more learning-based mechanisms of parental behavior in rodents.

Why does quality of life remain an under-investigated issue in chronic kidney disease and why is it rarely set as an outcome measure in trials in this population?

The growing importance of quality of life (QoL) measures in health care is reflected by the increased volume and rigor of published research on this topic. The ability to measure and assess patients' experience of symptoms and functions has transformed the development of disease treatments and interventions. However, QoL remains an under-investigated issue in chronic kidney disease (CKD) and is seldom set as an outcome measure in trials in this population. In this article, we present various challenges in using patient-reported outcome (PRO) end points in CKD trials. We outline the need for additional research to examine more closely patient experiences with specific kidney disease symptoms and conditions, as well as caregiver perspectives of patients' symptom burden and end-of-life experiences. These efforts will better guide the development or enhancement of PRO instruments that can be used in clinical trials to more effectively assess treatment benefit, and improve therapy and care. Better understanding of health-related QoL issues would enable providers to deliver more patient-centered care and improve the overall well-being of patients. Even small improvements in QoL could have a large impact on the population's overall health and disease burden.

Behavioral relevance helps untangle natural vocal categories in a specific subset of core auditory cortical pyramidal neurons.

Sound categorization is essential for auditory behaviors like acoustic communication, but its genesis within the auditory pathway is not well understood-especially for learned natural categories like vocalizations, which often share overlapping acoustic features that must be distinguished (e.g., speech). We use electrophysiological mapping and single-unit recordings in mice to investigate how representations of natural vocal categories within core auditory cortex are modulated when one category acquires enhanced behavioral relevance. Taking advantage of a maternal mouse model of acoustic communication, we found no long-term auditory cortical map expansion to represent a behaviorally relevant pup vocalization category-contrary to expectations from the cortical plasticity literature on conditioning with pure tones. Instead, we observed plasticity that improved the separation between acoustically similar pup and adult vocalization categories among a physiologically defined subset of late-onset, putative pyramidal neurons, but not among putative interneurons. Additionally, a larger proportion of these putative pyramidal neurons in maternal animals compared with nonmaternal animals responded to the individual pup call exemplars having combinations of acoustic features most typical of that category. Together, these data suggest that higher-order representations of acoustic categories arise from a subset of core auditory cortical pyramidal neurons that become biased toward the combination of acoustic features statistically predictive of membership to a behaviorally relevant sound category.

Epigenome-wide DNA methylation landscape of melanoma progression to brain metastasis reveals aberrations on homeobox D cluster associated with prognosis.

Melanoma brain metastasis (MBM) represents a frequent complication of cutaneous melanoma. Despite aggressive multi-modality therapy, patients with MBM often have a survival rate of <1 year. Alteration in DNA methylation is a major hallmark of tumor progression and metastasis; however, it remains largely unexplored in MBM. In this study, we generated a comprehensive DNA methylation landscape through the use of genome-wide copy number, DNA methylation and gene expression data integrative analysis of melanoma progression to MBM. A progressive genome-wide demethylation in low CpG density and an increase in methylation level of CpG islands according to melanoma progression were observed. MBM-specific partially methylated domains (PMDs) affecting key brain developmental processes were identified. Differentially methylated CpG sites between MBM and lymph node metastasis (LNM) from patients with good prognosis were identified. Among the most significantly affected genes were the HOX family members. DNA methylation of HOXD9 gene promoter affected transcript and protein expression and was significantly higher in MBM than that in early stages. A MBM-specific PMD was identified in this region. Low methylation level of this region was associated with active HOXD9 expression, open chromatin and histone modifications associated with active transcription. Demethylating agent induced HOXD9 expression in melanoma cell lines. The clinical relevance of this finding was verified in an independent large cohort of melanomas (n = 145). Patients with HOXD9 hypermethylation in LNM had poorer disease-free and overall survival. This epigenome-wide study identified novel methylated genes with functional and clinical implications for MBM patients.

Patients with Crohn's Disease Are More Likely to Remain on Biologics than Immunomodulators: A Meta-Analysis of Treatment Durability.

BACKGROUND AND AIM: The comparative effectiveness of treatments for moderate-to-severe Crohn's disease can be influenced by the likelihood of remaining on medication. We aimed to clarify this treatment durability by assessing subject discontinuations from clinical trials in the context of treatment efficacy. METHODS: We conducted a literature search for double-blind RCT of Crohn's disease therapies recommended in international guidelines or with recent positive phase III trial results. Durability was defined through study discontinuation due to adverse events or disease exacerbation represented by number needed to discontinue (NND). Efficacy was defined as clinical remission represented by number needed to treat (NNT). The primary endpoint was NND/NNT, with a higher value representing more durable and effective treatment. RESULTS: Treatment with azathioprine/6-mercaptopurine (AZA/6MP) was associated with more discontinuations than with clinical remission (NND/NNT = 0.92) in maintenance trials. For induction, methotrexate was associated with similar rates of discontinuations and remission (NND/NNT = 1.4). In one maintenance trial, the remission rate for methotrexate was greater than the study discontinuation rate (NND/NNT = 23.3). In contrast, anti-TNF trials revealed greater durability among induction (no excess discontinuation) and maintenance (NND/NNT = 37.9) trials. Trials of anti-trafficking agents had fewer discontinuations in the drug treatment arms than placebo resulting in most favorable NND/NNT ratios. CONCLUSIONS: For patients with Crohn's disease, biologic therapies had higher durability than immunomodulators for induction and maintenance therapy. We also report the results of a novel NND/NNT ratio that should be validated in a prospective head-to-head placebo-controlled trial.

Genome-wide characterization of circulating tumor cells identifies novel prognostic genomic alterations in systemic melanoma metastasis.

BACKGROUND: Circulating tumor cells (CTC) have been found in patients with metastatic melanoma and are associated with advanced melanoma stage and poor patient outcome. We hypothesize that CTC harbor genomic changes critical in the development of distant systemic metastasis. Here, we present the first genome-wide copy-number aberration (CNA) and loss of heterozygosity (LOH)-based characterization of melanoma CTC. METHODS: CTC were isolated from peripheral blood monocytes of 13 melanoma patients with regional metastasis stage IIIB/C using antibodies against melanoma-associated cell surface gangliosides. RESULTS: We characterized 251 CNA in CTC. Comparative analysis demonstrated >90% concordance in single-nucleotide polymorphism profiles between paired CTC and tumor metastases. In particular, there were notable recurring CNA across patients. In exploratory studies, the presence of several top CTC-associated CNA was verified in distant metastasis (stage IV) from 27 patients, suggesting that certain genomic changes are propagated from regional metastasis to CTC and to distant systemic metastases. Lastly, an exploratory biomarker panel derived from 5 CTC-associated CNA [CSMD2 (CUB and Sushi multiple domains 2), 1p35.1; CNTNAP5 (contactin associated protein-like 5), 2q14.3; NRDE2 (NRDE-2, necessary for RNA interference, domain containing), 14q32.11; ADAM6 (ADAM metallopeptidase domain 6, pseudogene), 14q32.33; and TRPM2 (transient receptor potential cation channel, subfamily m, member 2), 21q22.3] conferred prognostic utility for melanoma recurrence [hazard ratio (HR), 1.14; CI, 1.00-1.44; P = 0.0471] and death (HR, 2.86; CI, 1.23-14.42; P = 0.0014) in 35 patients with stage IIIB/C melanoma, with a 5-year disease-free survival of 13% vs 69% (P = 0.0006) and overall survival of 28% vs 94% between high-risk and low-risk groups defined by the biomarker panel, respectively. CONCLUSIONS: This study provides the first detailed CNA-based profile of melanoma CTC and illustrates how CTC may be used as a novel approach for identification of systemic metastasis.

Epigenetic regulation of cancer stem cell genes in triple-negative breast cancer.

Expression of specific breast cancer stem cells (BCSCs) is seen in aggressive tumors, but their regulation is unclear. Epigenetic changes influence gene expression and are implicated in breast cancer progression. We hypothesized that promoter methylation regulates specific BCSC-related genes [CD44, CD133, CD24, MSH1 (alias, Musashi-1), and ALDH1] and that this epigenetic profile can identify aggressive subtypes, such as triple-negative breast cancer (TNBC). Methylation analysis was performed using MassARRAY EpiTYPER sequencing; CpG-rich sites were identified in the promoter regions of BCSC genes, except ALDH1. These sites were screened by treatment with 5-aza-2'-deoxycytidine in four TN and five non-TNBC cell lines. The specific regulatory CpG site demonstrating the most significant inverse correlation between CpG site methylation and mRNA expression was identified for CD44, CD133, and Musashi-1, but not for CD24. Methylation of CD44, CD133, and Musashi-1 was evaluated in 91 American Joint Committee on Cancer stage I to III primary breast cancer tumors, and these sites were significantly hypomethylated in TNBC versus non-TNBC. The IHC staining of primary tumors with the highest and lowest methylation levels revealed the strongest staining in hypomethylated specimens, suggesting that hypomethylation leads to gene activation. We demonstrate that methylation is a significant mechanism regulating CD44, CD133, and Musashi-1, and that gene hypomethylation correlates with TNBC. Assessment of epigenetic changes in BCSC genes may provide a more accurate classification of TNBC and could be developed as potential therapeutic targets.

Molecular mechanisms of metastasis.

The mechanism of metastasis is a complex set of events that build upon each other to achieve successful growth in organ sites beyond the primary tumor. The cumulative events for metastasis of different cancers have both common and specific cancer specific events. This review discusses several key factors in different cancers that are responsible in metastasis, which includes epigenetic regulation of tumor suppressor genes, functional activity of tumor-related chemokine receptors, and circulating tumor cells.

Methane on breath testing is associated with constipation: a systematic review and meta-analysis.

BACKGROUND: A growing body of literature suggests an association between methane and constipation. Studies also link degree of methane production to severity of constipation and have shown constipation is improved following antibiotics. AIMS: We aim to conduct a systematic review and meta-analysis to examine the cumulative evidence regarding the association between methane and constipation. METHODS: A literature search was performed using MEDLINE and Embase to identify studies where the presence (or absence) of methane was assessed in constipated subjects. Search terms included "methane," "breath test," "constipation," "motility," "transit," "irritable bowel syndrome" and/or "IBS." Pooled odds ratios were generated using a random effects model. In a separate analysis, studies that measured intestinal transit in methane and non-methane subjects were systematically reviewed. RESULTS: Nine studies met inclusion criteria for the meta-analysis. Among these, 1,277 subjects were examined by breath testing (N = 319 methane producers and N = 958 methane non-producers). Pooling all studies, a significant association was found between methane on breath test and constipation (OR = 3.51, CI = 2.00-6.16). Among adults only, methane was significantly associated with constipation (OR = 3.47, CI = 1.84-6.54). Similar results were seen when only examining subjects with IBS (OR = 3.60, CI = 1.61-8.06). The systematic review identified eight additional papers which all demonstrated an association between methane and delayed transit. CONCLUSIONS: We demonstrate that methane present on breath testing is significantly associated with constipation in both IBS and functional constipation. These results suggest there may be merit in using breath testing in constipation. Moreover, methane may be used to identify candidates for antibiotic treatment of constipation.

Reconsidering Donor Race in Predicting Allograft and Patient Survival Among Kidney Transplant Recipients.

Donor race should not be used in models to predict allograft and patient survival.Removing donor race from the Kidney Donor Risk Index may reduce kidney discard by reclassifying approximately 50% of high kidney donor profile index kidneys.Future prediction models should focus on using relevant biologic factors rather than social constructs when trying to predict outcomes.

Abnormal breath testing in IBS: a meta-analysis.

BACKGROUND: Recent evidence suggests a role for enteric bacteria in the development of symptoms in subjects with irritable bowel syndrome (IBS). The concept was initially based on the common finding of an abnormal lactulose breath test to suggest the presence of small intestinal bacterial overgrowth (SIBO). Despite successful antibiotic studies based on these findings, the premise of bacterial overgrowth was met with skepticism due to the perceived inaccuracies of breath testing in humans. In this study, we conduct a systematic review and meta-analysis of the studies using breath testing in IBS subjects with comparison to healthy controls. METHODS: A literature search was conducted to identify studies in which breath testing was conducted in subjects with IBS. Once abstract titles were identified, studies that examined breath testing in a case-control fashion were identified for paper review. After exclusion criteria were applied, the remaining papers were examined using meta-analysis, among which the prevalence of an abnormal breath test in IBS subjects was compared. Further analysis was conducted among studies with appropriate age- and sex-matched controls. RESULTS: Eleven studies met criteria for inclusion in the meta-analysis. Although heterogeneity was identified among studies on the basis of substrate used, lactulose was the most common substrate. In pooling the 11 studies, breath testing was more often abnormal among IBS subjects than health controls (OR=4.46, 95% CI=1.69-11.80). This was further evident in more appropriately designed age- and sex-matched studies (OR=9.64, 95% CI=4.26-21.82). The overall sensitivity and specificity for breath testing in separating IBS from healthy controls was 43.6 and 83.6%. CONCLUSIONS: This study demonstrates that the breath test findings in IBS appear to be valid. While this meta-analysis does not suggest that the breath test findings imply SIBO, the abnormal fermentation timing and dynamics of the breath test findings support a role for abnormal intestinal bacterial distribution in IBS.

How do proxy responses and proxy-assisted responses differ from what Medicare beneficiaries might have reported about their health care?

OBJECTIVE: Assess proxy respondent effects on health care evaluations by Medicare beneficiaries. DATA SOURCE: 110,215 respondents from the nationally representative 2001 CAHPS((R)) Medicare Fee-for-Service Survey. STUDY DESIGN/DATA COLLECTION/EXTRACTION METHODS: We compare the effects of both proxy respondents and proxy assistance (reading, writing, or translating) on 23 "objective" report items and four "subjective" global measures of health care experiences using propensity-score-weighted regression. We assess whether proxy effects differ among spouses, other relatives, or nonrelatives. PRINCIPAL FINDINGS: Proxy respondents provide less positive evaluations of beneficiary health care experiences than otherwise similar self-reporting beneficiaries for more subjective global ratings (average effect of 0.21 standard deviations); differences are smaller for relatively objective and specific report items. Proxy assistance differences are similar, but about half as large. Reports from spouse proxy respondents are more positive than those from other proxies and are similar to what would have been reported by the beneficiaries themselves. Standard regression techniques may overestimate proxy effects in this instance. CONCLUSIONS: One should treat proxy responses to subjective ratings cautiously. Even seemingly innocuous reading, writing, and translation by proxies may influence answers. Spouses may be accurate proxies for the elderly in evaluations of health care.

Familiarity with social sounds alters c-Fos expression in auditory cortex and interacts with estradiol in locus coeruleus.

When a social sound category initially gains behavioral significance to an animal, plasticity events presumably enhance the ability to recognize that sound category in the future. In the context of learning natural social stimuli, neuromodulators such as norepinephrine and estrogen have been associated with experience-dependent plasticity and processing of newly salient social cues, yet continued plasticity once stimuli are familiar could disrupt the stability of sensorineural representations. Here we employed a maternal mouse model of natural sensory cortical plasticity for infant vocalizations to ask whether the engagement of the noradrenergic locus coeruleus (LC) by the playback of pup-calls is affected by either prior experience with the sounds or estrogen availability, using a well-studied cellular activity and plasticity marker, the immediate early gene c-Fos. We counted call-induced c-Fos immunoreactive (c-Fos-IR) cells in both LC and physiologically validated fields within the auditory cortex (AC) of estradiol or blank-implanted virgin female mice with either 0 or 5-days prior experience caring for vocalizing pups. Estradiol and pup experience interacted both in the induction of c-Fos-IR in the LC, as well as in behavioral measures of locomotion during playback, consistent with the neuromodulatory center's activity being an online reflection of both hormonal and experience-dependent influences on arousal. Throughout core AC, as well as in a high frequency sub-region of AC and in secondary AC, a main effect of pup experience was to reduce call-induced c-Fos-IR, irrespective of estradiol availability. This is consistent with the hypothesis that sound familiarity leads to less c-Fos-mediated plasticity, and less disrupted sensory representations of a meaningful call category. Taken together, our data support the view that any coupling between these sensory and neuromodulatory areas is situationally dependent, and their engagement depends differentially on both internal state factors like hormones and external state factors like prior experience.

Low serum sodium levels at hospital admission: Outcomes among 2.3 million hospitalized patients.

BACKGROUND: Hyponatremia is the most common electrolyte disorder among hospitalized patients. Controversies still exist over the relationship between hyponatremia and outcomes of hospitalized patients. METHODS: To analyze the association of low serum sodium levels at hospital admission with in-hospital mortality and patient disposition and to compare the distribution of the risk of death associated with hyponatremia across the lifespan of hospitalized patients, we conducted an observational study of 2.3 million patients using data extracted from the Cerner Health Facts database between 2000 and 2014. Logistic regression models were used in the analyses. RESULTS: At hospital admission 14.4% of hospitalized patients had serum sodium levels [Na] <135 mEq/L. In adjusted multinomial logistic regression analysis, we found that the risk of in-hospital mortality significantly increases for [Na] levels < 135 or ≥143 to ≤145 mEq/L compared to the reference interval of 140 to <143 mEq/L (p<0.001). We observed similar trends for the relationship between [Na] levels and discharge to hospice or to a nursing facility. We demonstrated that younger age groups (18 to <45, 45 to <65) had a higher risk of in-hospital mortality compared to older age groups (65 to <75, ≥75) for [Na] levels <130 mEq/L or 143 to ≤145 mEq/L (p<0.001). CONCLUSIONS: Hyponatremia is common among hospitalized patients and is significantly associated with in-hospital mortality, discharge to hospice or to a nursing facility. The risk of death and other outcomes was more evident for [Na] <135 mEq/L. The mortality associated with low [Na] was significantly higher in younger versus older patients.

Risk for Overall Infection with Anti-TNF and Anti-integrin Agents Used in IBD: A Systematic Review and Meta-analysis.

BACKGROUND: The overall risk for infection with contemporary biological agents in treating Crohn's disease (CD) and ulcerative colitis (UC) has not been systematically assessed. METHODS: We performed a PubMed and Cochrane database literature search to evaluate randomized, placebo-controlled trials of biologics in treating UC and CD. Meta-analysis was performed using a DerSimonian and Laird random effects model. We determined relative risk (RR) of harm against placebo; number needed to harm (NNH) was reported when appropriate. Heterogeneity and publication bias were assessed. RESULTS: Fourteen trials (6 UC and 8 CD) evaluating 5107 patients were included. For anti-tumor necrosis factor agents used in the treatment of UC, golimumab {NNH of 9.3, RR = 1.4 (95% confidence interval [CI], 1.04-1.8)} and pooled studies of infliximab and adalimumab (NNH = 17.2, RR = 1.2 [95% CI, 1.0-1.3]) had a statistically significant higher risk for any infection versus placebo. Risk was not significantly increased in anti-tumor necrosis factor trials in CD (RR = 1.1 [95% CI, 0.8-1.5]). By contrast, anti-integrin agents in UC (RR = 1.0 [95% CI, 0.9-1.2]) or CD (RR = 1.1 [95% CI, 0.97-1.3]) did not confer a statistically significant excess risk of infection versus placebo. CONCLUSIONS: Anti-tumor necrosis factor therapy but not anti-integrin therapy is associated with a greater infection risk than placebo in treating UC. Neither class of therapy is associated with increased infection risk over placebo in treating CD. Our findings can help guide patient-centered discussions regarding the risk for infection with biological agents.

Infrequent Provision of Palliative Care to Patients with Dialysis-Requiring AKI.

BACKGROUND AND OBJECTIVES: The use of palliative care in AKI is not well described. We sought to better understand palliative care practice patterns for hospitalized patients with AKI requiring dialysis in the United States. DESIGN, SETTING, PARTICIPANTS, & MEASUREMENTS: Using the 2012 National Inpatient Sample, we identified patients with AKI and palliative care encounters using validated International Classification of Diseases, Ninth Revision, Clinical Modification codes. We compared palliative care encounters in patients with AKI requiring dialysis, patients with AKI not requiring dialysis, and patients without AKI. We described the provision of palliative care in patients with AKI requiring dialysis and compared the frequency of palliative care encounters for patients with AKI requiring dialysis with that for patients with other illnesses with similarly poor prognoses. We used logistic regression to determine factors associated with the provision of palliative care, adjusting for demographics, hospital-level variables, and patient comorbidities. RESULTS: We identified 3,031,036 patients with AKI, of whom 91,850 (3%) received dialysis. We observed significant patient- and hospital-level differences in the provision of palliative care for patients with AKI requiring dialysis; adjusted odds were 26% (95% confidence interval, 12% to 38%) lower in blacks and 23% (95% confidence interval, 3% to 39%) lower in Hispanics relative to whites. Lower provision of palliative care was observed for rural and urban nonteaching hospitals relative to urban teaching hospitals, small and medium hospitals relative to large hospitals, and hospitals in the Northeast compared with the South. After adjusting for age and sex, there was low utilization of palliative care services for patients with AKI requiring dialysis (8%)-comparable with rates of utilization by patients with other illnesses with poor prognosis, including cardiogenic shock (9%), intracranial hemorrhage (10%), and acute respiratory distress syndrome (10%). CONCLUSIONS: The provision of palliative care varied widely by patient and facility characteristics. Palliative care was infrequently used in hospitalized patients with AKI requiring dialysis, despite its poor prognosis and the regular application of life-sustaining therapy.