MetaBMF: a scalable binning algorithm for large-scale reference-free metagenomic studies.

MOTIVATION: Metagenomics studies microbial genomes in an ecosystem such as the gastrointestinal tract of a human. Identification of novel microbial species and quantification of their distributional variations among different samples that are sequenced using next-generation-sequencing technology hold the key to the success of most metagenomic studies. To achieve these goals, we propose a simple yet powerful metagenomic binning method, MetaBMF. The method does not require prior knowledge of reference genomes and produces highly accurate results, even at a strain level. Thus, it can be broadly used to identify disease-related microbial organisms that are not well-studied. RESULTS: Mathematically, we count the number of mapped reads on each assembled genomic fragment cross different samples as our input matrix and propose a scalable stratified angle regression algorithm to factorize this count matrix into a product of a binary matrix and a nonnegative matrix. The binary matrix can be used to separate microbial species and the nonnegative matrix quantifies the species distributions in different samples. In simulation and empirical studies, we demonstrate that MetaBMF has a high binning accuracy. It can not only bin DNA fragments accurately at a species level but also at a strain level. As shown in our example, we can accurately identify the Shiga-toxigenic Escherichia coli O104: H4 strain which led to the 2011 German E.coli outbreak. Our efforts in these areas should lead to (i) fundamental advances in metagenomic binning, (ii) development and refinement of technology for the rapid identification and quantification of microbial distributions and (iii) finding of potential probiotics or reliable pathogenic bacterial strains. AVAILABILITY AND IMPLEMENTATION: The software is available at https://github.com/didi10384/MetaBMF.

The choice of comorbidity scoring system in Chinese peritoneal dialysis patients.

BACKGROUND: Several comorbidity scoring systems have been developed and validated, mostly in western hemodialysis patients with a high risk of cardiovascular disease. The performance of comorbidity scoring, however, depends on the patient population. In this study, we determine the optimal comorbidity scoring system for predicting survival of incident Chinese PD patients. METHODS: We studied 461 incident PD patients. The performance of Charlson Comorbidity Index (CCI), Hemmelgarn score, and Liu score as the survival predictor was compared. RESULTS: The mean age was 57.7 ± 13.7 years. The median CCI, Hemmelgarn, and Liu scores were 4 [inter-quartile range (IQR) 2-5], 1 (IQR 0-2), and 4 (IQR 2-5), respectively. Patients were followed for 45.5 ± 33.0 months. All 3 comorbidity scores were predictors of patient survival by univariate analysis. After adjusting for confounding factors, CCI was the best predictor of patient survival among the 3 indices, with each point increase in CCI conferring 31% excess in mortality risk [95% confidence interval (CI) 21-41%, p < 0.001]. In contrast, each point increase in Liu score confers 20% excess in mortality risk (95% CI 13-27%, p < 0.001). Although the Hemmelgarn score is an independent predictor of patient survival, over 70% of patients score 0 or 1 by this system, limiting its role as a prognostic marker. CONCLUSION: CCI should be the preferred method for quantifying comorbidity load in incident Chinese PD patients, and it is a good predictor of survival in this group of patients.

Causes of nephrotic syndrome and nephrotic-range proteinuria are different in adult Chinese patients: A single centre study over 33 years.

AIM: The reported causes of nephrotic syndrome (NS) varies between different countries. Less is known about the causes of nephrotic-range proteinuria (NPU). We aimed to evaluate the underlying causes of NS and NPU. METHODS: This was a single-centre, retrospective study of adult patients who underwent renal biopsy between 1983 and 2015 in a tertiary referral hospital in Hong Kong. We determined the distribution of histopathological diagnoses with regard to the age subgroups and time periods. RESULTS: Among 7456 patients who underwent renal biopsy, 982 and 838 patients had NS and NPU, respectively. The most common diagnosis in NS was minimal change disease (MCD) (33.3%), followed by membranous nephropathy (MN) (23.6%) and lupus nephritis (LN) (12.8%); whereas the most common diagnosis in NPU was LN (27.4%), followed by immunoglobulin A nephropathy (IgAN) (21.4%) and diabetic nephropathy (DN) (9.3%). In the NS group, MCD was the most common diagnosis in young adults while MN was the leading cause in the elderly. On the other hand, LN was the most common pathology in the NPU group until the age of 60. Over the past three decades, there was a trend of decrease in the proportion of IgAN in both NS and NPU group, while a combined pathology of hypertensive nephrosclerosis and diabetic nephropathy (HTNS and DN) increased significantly. CONCLUSIONS: The causes of NS and NPU in Chinese adults were different and may represent two distinct pathological identities. The spectrum of renal histopathology among these two groups changed significantly over time.

Targeting the tyrosine kinase signalling pathways for treatment of immune-mediated glomerulonephritis: from bench to bedside and beyond.

Glomerulonephritis (GN) affects patients of all ages and is an important cause of morbidity and mortality. Non-selective immunosuppressive drugs have been used in immune-mediated GN but often result in systemic side effects and occasionally fatal infective complications. There is increasing evidence from both preclinical and clinical studies that abnormal activation of receptor and non-receptor tyrosine kinase signalling pathways are implicated in the pathogenesis of immune-mediated GN. Activation of spleen tyrosine kinase (SYK), Bruton's tyrosine kinase (BTK), platelet-derived growth factor receptor (PDGFR), epidermal growth factor receptor (EGFR) and discoidin domain receptor 1 (DDR1) have been demonstrated in anti-GBM disease. SYK is implicated in the pathogenesis of ANCA-associated GN. SYK, BTK, PDGFR, EFGR, DDR1 and Janus kinase are implicated in the pathogenesis of lupus nephritis. A representative animal model of IgA nephropathy (IgAN) is lacking. Based on the results from in vitro and human renal biopsy study results, a phase II clinical trial is ongoing to evaluate the efficacy and safety of fostamatinib (an oral SYK inhibitor) in high-risk IgAN patient. Various tyrosine kinase inhibitors (TKIs) have been approved for cancer treatment. Clinical trials of TKIs in GN may be justified given their long-term safety data. In this review we will discuss the current unmet medical needs in GN treatment and research as well as the current stage of development of TKIs in GN treatment and propose an accelerated translational research approach to investigate whether selective inhibition of tyrosine kinase provides a safer and more efficacious option for GN treatment.

Global impact of nephropathies.

The global burden of chronic kidney disease (CKD) has increased substantially in recent years, partly attributed to the global epidemic of diabetes mellitus. In many countries including China, glomerulonephritis was the most common cause of end stage renal disease (ESRD). The mortality rate of dialysis patients can be as high as patients with colon, breast and prostate cancers. CKD has important socio-economic impact on the healthcare system and society. Increasing awareness and early detection of CKD cannot be overemphasized. In places where healthcare resources are limited, peritoneal dialysis first policy has allowed local governments and health authorities to maximize healthcare resources to provide renal replacement therapy for more ESRD patients. In conclusion, management of CKD remains a global health challenge and continued medical research is most important.

Manifestation of tranexamic acid toxicity in chronic kidney disease and kidney transplant patients: A report of four cases and review of literature.

AIM: Tranexamic acid (TXA) is a synthetic anti-fibrinolytic agent commonly used for the prevention and treatment of bleeding disorders. The aim of this study is to describe the clinical manifestation of TXA toxicity in chronic kidney disease (CKD) patients. METHODS: From 2005 to 2014, we encountered four CKD patients who experienced severe complications related to TXA. Clinical manifestations and outcome of these patients were recorded. We then performed a qualitative literature review of published cases of TXA toxicity in CKD patients in the PubMed database from 1 January 1972 to 31 December 2015. RESULTS: In our centre, two peritoneal dialysis (PD) patients developed neurotoxicity after intravenous TXA use for surgical bleeding and one PD patient developed neurotoxicity after oral TXA use for post-polypectomy colonic bleeding. One kidney transplant recipient developed acute obstructive uropathy due to retention of blood clot at the pelvi-ureteric junction of graft kidney after taking oral TXA for menorrhagia. Dosage of TXA was not adjusted according to renal function in all cases. All of them recovered without permanent disability after TXA was stopped. From our literature search, we identified two cases of neurotoxicity (one PD, one stage 4 CKD patient), one case of retinal toxicity in a haemolysis (HD) patient, one case of ligneous conjunctivitis in a CKD patient, and one case of toxic epidermal necrolysis in a CKD patient. CONCLUSION: Neurotoxicity is a very common clinical manifestation of TXA toxicity in CKD patients. Thrombotic complication is rare. Dosage adjustment of TXA is essential in CKD patients.

Depression in dialysis patients.

Depression is the most common psychiatric illness in patients with end-stage renal disease (ESRD). The reported prevalence of depression in dialysis population varied from 22.8% (interview-based diagnosis) to 39.3% (self- or clinician-administered rating scales). Such differences were attributed to the overlapping symptoms of uraemia and depression. Systemic review and meta-analysis of observational studies showed that depression was a significant predictor of mortality in dialysis population. The optimal screening tool for depression in dialysis patients remains uncertain. The Beck Depression Inventory (BDI), Patient Health Questionnaire (PHQ) and Center for Epidemiologic Studies Depression Scale (CESD) have been validated for screening purposes. Patients who scored ≥14 using BDI should be referred to a psychiatrist for early evaluation. Structured Clinical Interview for DSM disorders (SCID) remains the gold standard for diagnosis. Non-pharmacological treatment options include cognitive behavioural therapy and exercise training programs. Although frequent haemodialysis may have beneficial effects on patients' physical and mental well-being, it cannot and should not be viewed as a treatment of depression. Selective serotonin reuptake inhibitors (SSRIs) are generally effective and safe in ESRD patients, but most studies were small, non-randomized and uncontrolled. The European Renal Best Practice (ERBP) guideline suggests a trial of SSRI for 8 to 12 weeks in dialysis patients who have moderate-major depression. The treatment effect should be re-evaluated after 12 weeks to avoid prolonging ineffective medication. This review will discuss the current understanding in the diagnosis and management of depression in dialysis patients.

Dialysate bacterial endotoxin as a prognostic indicator of peritoneal dialysis related peritonitis.

Peritonitis is the major complication of peritoneal dialysis (PD). The aim of our present study is to explore the prognostic value of endotoxin level in PD effluent for the prediction of treatment failure in PD-related peritonitis. We studied 325 peritonitis episodes in 223 patients. PD effluent (PDE) was collected every 5 days for endotoxin level and leukocyte count. Patients were followed for relapsing or recurrent peritonitis. We found 20 episodes (6.2%) had primary treatment failure; 41 (12.6%) developed relapsing, 19 (5.8%) had recurrent, and 22 (6.8%) had repeat episodes. Endotoxin was detectable in the PDE of 19 episodes (24.4%) caused by Gram negative organisms, 4 episodes (6.8%) of mixed bacterial growth, and none of the culture negative episodes or those by Gram positive organisms. For episodes caused by Gram negative bacteria, a detectable endotoxin level in PDE on day 5 had a sensitivity and specificity of 66.7% and 83.3%, respectively, for predicting primary treatment failure. In contrast, PDE leukocyte count > 1000 per mm3 on day 5 had a sensitivity and specificity of 88.9% and 89.1%, respectively; the addition of PDE endotoxin assay did not improve the sensitivity or specificity. We conclude that detectable endotoxin in PDE 5 days after antibiotic therapy might predict primary treatment failure in peritonitis episodes caused by Gram negative organisms. However, the sensitivity and specificity of PDE endotoxin assay was inferior to PDE leukocyte count.

Podocyte mRNA in the urinary sediment of minimal change nephropathy and focal segmental glomerulosclerosis.

BACKGROUND: Podocyte depletion is a characteristic feature of progressive renal failure. We hypothesize that studying the podocyte mRNA level in urinary sediment may provide diagnostic and prognostic information in adult nephrotic syndrome. METHODS: We studied 25 patients with minimal change nephropathy (MCN), 25 with focal segmental glomerulosclerosis (FSGS), and 17 healthy controls. The mRNA levels of nephrin, podocin, and synaptopodin in urinary sediment were quantified. RESULTS: There were significant differences in the urinary sediment nephrin and podocin, but not synaptopodin, mRNA levels between diagnosis groups. Post-hoc analysis further showed that urinary nephrin mRNA levels of the MCN group were lower than those in the control and FSGS groups, although the difference between MCN and FSGS groups did not reach statistical significance. The degree of proteinuria inversely correlated with urinary nephrin mRNA levels in the MCN (r = -0.526, p = 0.007) as well as in the FSGS group (r = -0.521, p = 0.008). For the FSGS group, the rate of renal function decline significantly correlated with baseline urinary synaptopodin mRNA levels (r = -0.496, p = 0.012). CONCLUSIONS: Urinary nephrin and podocin mRNA levels were reduced in patients with MCN and probably FSGS, and the magnitude of reduction correlated with the degree of proteinuria. Urinary synaptopodin mRNA levels correlated with the subsequent rate of renal function decline in patients with FSGS. Our result indicates that urine sediment podocyte mRNA levels provide novel insights in the pathophysiology of nephrotic syndrome and could be useful for risk stratification.

Randomized controlled study of icodextrin on the treatment of peritoneal dialysis patients during acute peritonitis.

BACKGROUND: The clinical benefits of using icodextrin during acute peritonitis in peritoneal dialysis are uncertain. On the premise that high glucose concentration might jeopardize the peritoneal defense during peritonitis, icodextrin administration during acute peritonitis could have the potential to improve the peritonitis outcome whilst improving ultrafiltration. METHODS: We conducted a single-center, open-label, randomized controlled trial in which 53 adult continuous ambulatory peritoneal dialysis patients underwent randomization to receive either icodextrin or original glucose-based dialysis solution. The primary outcome measure was the peritoneal dialyzate white cell count on Day 3. Secondary outcome measures comprised the need of additional hypertonic exchanges, fluid control as denoted by changes in body weight, and the clinical outcome of peritonitis including 30-day and 120-day all-cause mortality. RESULTS: Between icodextrin and control treatment groups, there were no statistically significant differences in the peritoneal dialyzate white cell count on day (1829 versus 987/mm(3), P = 0.13). There was neither improvement in primary cure rate (31.8 versus 32.3%, P = 1.00), nor was there any change in 120-day mortality after icodextrin use (13.6 versus 12.9%, P = 1.00). However, requirement of hypertonic dialysis exchange was much more frequent in the control group than in those randomized to icodextrin (35.5 versus 0%, P = 0.001). Body weight did not change significantly in the icodextrin group, but body weight in the control group increased from 63.3 ± 14.5 kg at baseline to 64.2 ± 14.2 kg at Day 5 (P = 0.0002) and 65.2 ± 14.1 kg at Day 10 (P < 0.0001). CONCLUSIONS: As compared with glucose-based peritoneal dialysis solution, use of icodextrin achieved better ultrafiltration and fluid control during acute peritonitis complicating continuous ambulatory peritoneal dialysis, although we found no evidence of a worthwhile clinical benefit on peritonitis resolution. (ClinicalTrial.gov number, NCT0104446 [ClinicalTrial.gov].).

Peritoneal-dialysis related peritonitis caused by Gordonia species: report of four cases and literature review.

AIM: To investigate the clinical course and outcome of peritoneal dialysis-associated peritonitis secondary to Gordonia species. METHOD: We reviewed all Gordonia peritonitis episodes occurring in a single dialysis unit from 1994 to 2013. RESULTS: During the study period, four episodes of Gordonia peritonitis were recorded. All were male patients. One patient responded to vancomycin therapy. One patient had refractory peritonitis despite vancomycin, but responded to imipenem and amikacin combination therapy. One patient had relapsing peritonitis and required catheter removal. The fourth patient had an elective Tenckhoff catheter exchange. No patient died of peritonitis. Causative organism was not fully identified until 7 to 18 days of peritonitis. CONCLUSION: Gordonia species is increasingly recognized to cause serious infections. In patients undergoing peritoneal dialysis, Gordonia peritonitis should be considered in case of refractory Gram-positive bacilli peritonitis, especially when the exact organism could not be identified one week after the onset of peritonitis. A close liaison with a microbiologist is needed for a timely diagnosis.

Effect of using ultrapure dialysate for hemodialysis on the level of circulating bacterial fragment in renal failure patients.

BACKGROUND: Cardiovascular disease is the major cause of mortality and morbidity in dialysis patients. Recently, circulating endotoxin is found to associate with the systemic inflammatory state and cardiovascular disease of dialysis patients. Previous studies showed that the use of ultrapure dialysate for hemodialysis could reduce the exposure to exogenous endotoxin. We studied the effect of using ultrapure dialysate for hemodialysis on circulating endotoxin and bacterial DNA fragment levels and vascular stiffness. METHODS: This is an open-labeled prospective study of 25 patients (14 male). Circulating endotoxin and bacterial DNA level, vascular stiffness as represented by arterial pulse wave velocity (PWV), nutrition and hydration status were monitored before and repeatedly throughout 12 months after the use of ultrapure dialysate for hemodialysis. RESULTS: The average age was 58.9 ± 10.2 years; 21 patients completed the study. Within 4 weeks of conversion to ultrapure dialysate for hemodialysis, the plasma endotoxin level fell from 0.302 ± 0.083 to 0.209 ± 0.044 EU/ml (p < 0.0001) and then remained static, while serum bacterial DNA level remained similar. Furthermore, the time-averaged plasma endotoxin level during the study period significantly correlated with serum C-reactive protein level (r = 0.483, p = 0.017), carotid-femoral PWV (r = 0.455, p = 0.033), and malnutrition inflammation score (r = 0.461, p = 0.031). The time-averaged serum bacterial DNA level significantly correlated with malnutrition inflammation score (r = 0.550, p = 0.008) and inversely with subjective global assessment score (r = -0.543, p = 0.009), but not with PWV. CONCLUSIONS: In hemodialysis patients, circulating endotoxin level is associated with vascular stiffness and systemic inflammation. Using ultrapure dialysate for hemodialysis effectively reduces circulating endotoxin level in hemodialysis patients. The long-term benefit of using ultrapure dialysate for hemodialysis requires further study.

Automated peritoneal dialysis in Hong Kong: there are two distinct groups of patients.

AIM: To compare the clinical outcome between continuous ambulatory peritoneal dialysis (CAPD) and automated peritoneal dialysis (APD) in specific subgroups of patients. METHODS: We reviewed the clinical outcome of 90 consecutive incident APD patients and 180 CAPD patients in our centre. RESULTS: The median follow up was 21.9 months (inter-quartile range, 9.5 to 46.5 months). The APD group was younger and had a lower Charlson's score than the CAPD group. Furthermore, the APD group had a highly skewed distribution of the Charlson's score, indicating the possibility of two different groups of patients. Multivariate analysis showed that in addition to the treatment mode (APD vs CAPD) and Charlson's score, there was a significant interaction between the two (P = 0.043) on patient survival. For patients with Charlson's score ≤6, the APD group had a significantly better patient survival than the CAPD group (78.3% vs. 65.4% at 5 years, P = 0.039), while for patients with Charlson's score ≥7, the APD group had a worse patient survival than the CAPD group (16.3% vs. 48.4% at 5 years, P = 0.028). Similarly, Charlson's score and its interaction with treatment mode, but not the APD group per se, were independent predictors of technique survival (P = 0.013). For patients with Charlson's score ≥7, the APD group had a significantly lower technique survival than the CAPD group (8.8% vs. 34.3%, P = 0.001), while for patients with Charlson's score ≤6, the technique survival was similar (44.4% vs. 42.5%, P = 0.15). Peritonitis-free survival was 35.2% and 32.2% for APD and CAPD groups, respectively (P = 0.021), and the difference was not affected by Charlson's score. CONCLUSIONS: Comorbid diseases had a significant interaction with the mode of PD on patient and technique survival of incident PD patients. Our result suggests that APD may offer benefit in, and only in, young patients with minimal comorbid diseases.

Broad H3K4me3 Domain Is Associated with Spatial Coherence during Mammalian Embryonic Development.

It is well known that the chromatin states play a major role in cell-fate decision and cell-identity maintenance; however, the spatial variation of chromatin states in situ remains poorly characterized. Here, by leveraging recently available spatial-CUT&Tag data, we systematically characterized the global spatial organization of the H3K4me3 profiles in a mouse embryo. Our analysis identified a subset of genes with spatially coherent H3K4me3 patterns, which together delineate the tissue boundaries. The spatially coherent genes are strongly enriched with tissue-specific transcriptional regulators. Remarkably, their corresponding genomic loci are marked by broad H3K4me3 domains, which is distinct from the typical H3K4me3 signature. Spatial transition across tissue boundaries is associated with continuous shortening of the broad H3K4me3 domains as well as expansion of H3K27me3 domains. Our analysis reveals a strong connection between the genomic and spatial variation of chromatin states, which may play an important role in embryonic development.

Mineralocorticoid receptor antagonist for renal protection.

The renin-angiotensin system (RAS) plays an important role in the pathophysiology of cardiovascular and renal diseases. In chronic kidney disease (CKD), blockade of RAS by angiotensin-converting enzyme inhibitor (ACEI) or angiotensin receptor blocker (ARB) has been shown to reduce proteinuria and retard the progression of renal function deterioration. However, aldosterone, another key hormone of the RAS, is not directly targeted by ACEI or ARB. Hyperaldosteronism, apart from promoting sodium and fluid retention, causes inflammation and fibrosis in the heart and kidney. Studies have shown that although plasma aldosterone level shows an initial decrease following ACEI or ARB treatment, it returns to pretreatment level or even increases paradoxically after prolonged treatment. This "aldosterone breakthrough" forms the basis of adding mineralocorticoid receptor (MR) antagonist on top of ACEI or ARB for renal protection. New insights into the pathophysiological role of aldosterone in CKD further expands its potential indications, and there was a growing body of evidence in the past 10 years, which showed a substantial antiproteinuric effect and possibly a considerable renoprotective effect of MR antagonist. Since aldosterone does not act on the efferent glomerular arteriole and has no effect on intraglomerular hemodynamics, the very fact that MR antagonist ameliorates proteinuria sheds light on the physiology of glomerular permeability barrier. This review summarizes the data regarding the theoretical benefit as well as clinical use of MR antagonist in renal diseases.

Variability in response to clopidogrel: how important are pharmacogenetics and drug interactions?

Clopidogrel is a pro-drug which is converted to an active metabolite that selectively blocks ADP-dependent platelet activation and aggregation. The main enzyme responsible for activating clopidogrel is the cytochrome P450 (CYP) isoenzyme CYP2C19, which is polymorphic. There is a growing body of literature showing that carriers of variant CYP2C19 alleles have impaired ability to metabolize clopidogrel (i.e. poor metabolizers), which is associated with decreased inhibition of platelet aggregation and increased cardiovascular risk. Some proton pump inhibitors are also metabolized by the CYP2C19 enzyme and often given together with clopidogrel to reduce gastrointestinal side effects. In particular, omeprazole has been shown to inhibit the CYP-mediated metabolism of clopidogrel, and some studies have shown that the combination was associated with a higher incidence of cardiovascular adverse reactions than clopidogrel given alone. However, a recent randomized controlled trial demonstrated no significant difference in adverse cardiovascular events for patients on the combination of clopidogrel and omeprazole compared with clopidogrel alone. This current review aims to summarize the role of pharmacogenetics and drug interactions in determining variability in response to clopidogrel.

Causes of mortality in patients with peptic ulcer bleeding: a prospective cohort study of 10,428 cases.

OBJECTIVES: Despite advances in endoscopic and pharmacological treatment for peptic ulcer bleeding (PUB), mortality remains at 5-10% worldwide. Our aim was to investigate the causes of death in a prospective cohort of PUB in a tertiary referral center. METHODS: Between 1993 and 2005, all patients with upper gastrointestinal bleeding (UGIB) admitted to the Prince of Wales Hospital were prospectively registered. Demographic data, characteristics of ulcer, and pharmacological, endoscopic, and surgical therapy, were documented. Mortality cases were classified as (A) bleeding-related death (A1: uncontrolled bleeding, A2: within 48 h after endoscopy, A3: during surgery for uncontrolled bleeding, A4: surgical complications or within 1 month after surgery, and A5: endoscopic related mortality) or (B) non-bleeding-related death (B1: cardiac causes, B2: pulmonary causes, B3: cerebrovascular disease, B4: multiorgan failure, and B5: terminal malignancy). RESULTS: In all, 18,508 cases of UGIB were enrolled; among them, 10,428 cases from 9,375 patients were confirmed to have PUB, and 577 (6.2%) patients died. There were significantly more patients who died of non-ulcer bleeding causes (79.7%) than bleeding causes (18.4%). The mean (s.d.) age of those who died of bleeding-related causes was higher (75.4 (12.6) years) than that of those who died of non-bleeding causes (71.7 (13.1) years) (P=0.010). Most bleeding-related deaths occurred when immediate control of bleeding failed (29.2%) or when patients died within 48 h after endoscopic therapy (25.5%). Among those who died of non-bleeding-related causes, multiorgan failure (23.9%), pulmonary conditions (23.5%), and terminal malignancy (33.7%) were most common. CONCLUSIONS: The majority of PUB patients died of non-bleeding-related causes. Optimization of management should aim at reducing the risk of multiorgan failure and cardiopulmonary death instead of focusing merely on successful hemostasis.