Machine learning approaches to the human metabolome in sepsis identify metabolic links with survival.

BACKGROUND: Metabolic predictors and potential mediators of survival in sepsis have been incompletely characterized. We examined whether machine learning (ML) tools applied to the human plasma metabolome could consistently identify and prioritize metabolites implicated in sepsis survivorship, and whether these methods improved upon conventional statistical approaches. METHODS: Plasma gas chromatography-liquid chromatography mass spectrometry quantified 411 metabolites measured ≤ 72 h of ICU admission in 60 patients with sepsis at a single center (Brigham and Women's Hospital, Boston, USA). Seven ML approaches were trained to differentiate survivors from non-survivors. Model performance predicting 28 day mortality was assessed through internal cross-validation, and innate top-feature (metabolite) selection and rankings were compared across the 7 ML approaches and with conventional statistical methods (logistic regression). Metabolites were consensus ranked by a summary, ensemble ML ranking procedure weighing their contribution to mortality risk prediction across multiple ML models. RESULTS: Median (IQR) patient age was 58 (47, 62) years, 45% were women, and median (IQR) SOFA score was 9 (6, 12). Mortality at 28 days was 42%. The models' specificity ranged from 0.619 to 0.821. Partial least squares regression-discriminant analysis and nearest shrunken centroids prioritized the greatest number of metabolites identified by at least one other method. Penalized logistic regression demonstrated top-feature results that were consistent with many ML methods. Across the plasma metabolome, the 13 metabolites with the strongest linkage to mortality defined through an ensemble ML importance score included lactate, bilirubin, kynurenine, glycochenodeoxycholate, phenylalanine, and others. Four of these top 13 metabolites (3-hydroxyisobutyrate, indoleacetate, fucose, and glycolithocholate sulfate) have not been previously associated with sepsis survival. Many of the prioritized metabolites are constituents of the tryptophan, pyruvate, phenylalanine, pentose phosphate, and bile acid pathways. CONCLUSIONS: We identified metabolites linked with sepsis survival, some confirming prior observations, and others representing new associations. The application of ensemble ML feature-ranking tools to metabolomic data may represent a promising statistical platform to support biologic target discovery.

Association between sepsis survivorship and long-term cardiovascular outcomes in adults: a systematic review and meta-analysis.

PURPOSE: We aimed to determine the association between sepsis and long-term cardiovascular events. METHODS: We conducted a systematic review of observational studies evaluating post-sepsis cardiovascular outcomes in adult sepsis survivors. MEDLINE, Embase, and the Cochrane Controlled Trials Register and Database of Systematic Reviews were searched from inception until April 21st, 2021. Two reviewers independently extracted individual study data and evaluated risk of bias. Random-effects models estimated the pooled crude cumulative incidence and adjusted hazard ratios (aHRs) of cardiovascular events compared to either non-septic hospital survivors or population controls. Primary outcomes included myocardial infarction, stroke, and congestive heart failure; outcomes were analysed at maximum reported follow-up (from 30 days to beyond 5 years post-discharge). RESULTS: Of 12,649 screened citations, 27 studies (25 cohort studies, 2 case-crossover studies) were included with a median of 4,289 (IQR 502-68,125) sepsis survivors and 18,399 (IQR 4,028-83,506) controls per study. The pooled cumulative incidence of myocardial infarction, stroke, and heart failure in sepsis survivors ranged from 3 to 9% at longest reported follow-up. Sepsis was associated with a higher long-term risk of myocardial infarction (aHR 1.77 [95% CI 1.26 to 2.48]; low certainty), stroke (aHR 1.67 [95% CI 1.37 to 2.05]; low certainty), and congestive heart failure (aHR 1.65 [95% CI 1.46 to 1.86]; very low certainty) compared to non-sepsis controls. CONCLUSIONS: Surviving sepsis may be associated with a long-term, excess hazard of late cardiovascular events which may persist for at least 5 years following hospital discharge.

Medical students' challenges and suggestions regarding research training: a synthesis of comments from a cross- sectional survey.

BACKGROUND: We previously reported on a cross-sectional study of students from the Michael G. DeGroote School of Medicine at McMaster University that found most respondents wanted more opportunities to participate in research. Students provided additional comments that we synthesized to enrich the findings of our quantitative analysis. METHODS: From our previously administered 13-item, online questionnaire, run across three campuses in Ontario, Canada, 498 of 618 medical students completed our survey and 360 (72%) provided optional written comments, which we synthesized using thematic analysis in this current study. RESULTS: Major themes that emerged were: (1) Active student participation to identify research opportunities and interested mentors are needed; (2) Types of research involvement; (3) Uncertainty whether research training translates into useable skills; (4) Desire for a formalized research curriculum and centralization of research opportunities across campuses. CONCLUSION: Programs should stress to interested students the importance of actively looking for research opportunities and consider both large and small-group educational sessions.

Evaluating Progression-Free Survival as a Surrogate Outcome for Health-Related Quality of Life in Oncology: A Systematic Review and Quantitative Analysis.

Importance: Progression-free survival (PFS) has become a commonly used outcome to assess the efficacy of new cancer drugs. However, it is not clear if delay in progression leads to improved quality of life with or without overall survival benefit. Objective: To evaluate the association between PFS and health-related quality of life (HRQoL) in oncology through a systematic review and quantitative analysis of published randomized clinical trials. Eligible trials addressed oral, intravenous, intraperitoneal, or intrapleural chemotherapy or biological treatments, and reported PFS or health-related quality of life. Data Sources: For this systematic review and quantitative analysis of randomized clinical trials of patients with cancer, we searched Medline, Embase, and the Cochrane Central Register of Controlled Trials from January 1, 2000, through May 4, 2016. Study Selection: Paired reviewers independently screened citations, extracted data, and assessed risk of bias of included studies. Data Extraction and Synthesis: We examined the association of difference in median PFS duration (in months) between treatment groups with difference in global, physical, and emotional HRQoL scores between groups (standardized to a range of 0-100, with higher scores representing better HRQoL) using weighted simple regressions. Main Outcome and Measure: The association between PFS duration and HRQoL. Results: Of 35 960 records screened, 52 articles reporting on 38 randomized clinical trials involving 13 979 patients across 12 cancer types using 6 different HRQoL instruments were included. The mean (SD) difference in median PFS between the intervention and the control arms was 1.91 (3.35) months. The mean (SD) differences in change of HRQoL adjusted to per-month values were -0.39 (3.59) for the global domain, 0.26 (5.56) for the physical domain, and 1.08 (3.49) for the emotional domain. The slope of the association between the difference in median PFS and the difference in change for global HRQoL (n = 30 trials) was 0.12 (95% CI, -0.27 to 0.52); for physical HRQoL (n = 20 trials) it was -0.20 (95% CI, -0.62 to 0.23); and for emotional HRQoL (n = 13 trials) it was 0.78 (95% CI, -0.05 to 1.60). Conclusions and Relevance: We failed to find a significant association between PFS and HRQoL in cancer clinical trials. These findings raise questions regarding the assumption that interventions prolonging PFS also improve HRQoL in patients with cancer. Therefore, to ensure that patients are truly obtaining important benefit from cancer therapies, clinical trial investigators should measure HRQoL directly and accurately, ensuring adequate duration and follow-up.

Early vasopressor use following traumatic injury: a systematic review.

OBJECTIVES: Current guidelines suggest limiting the use of vasopressors following traumatic injury; however, wide variations in practice exist. Although excessive vasoconstriction may be harmful, these agents may help reduce administration of potentially harmful resuscitation fluids. This systematic review aims to compare early vasopressor use to standard resuscitation in adults with trauma-induced shock. DESIGN: Systematic review. DATA SOURCES: We searched MEDLINE, EMBASE, ClinicalTrials.gov and the Central Register of Controlled Trials from inception until October 2016, as well as the proceedings of 10 relevant international conferences from 2005 to 2016. ELIGIBILITY CRITERIA FOR SELECTING STUDIES: Randomised controlled trials and controlled observational studies that compared the early vasopressor use with standard resuscitation in adults with acute traumatic injury. RESULTS: Of 8001 citations, we retrieved 18 full-text articles and included 6 studies (1 randomised controlled trial and 5 observational studies), including 2 published exclusively in abstract form. Across observational studies, vasopressor use was associated with increased short-term mortality, with unadjusted risk ratios ranging from 2.31 to 7.39. However, the risk of bias was considered high in these observational studies because patients who received vasopressors were systematically sicker than patients treated without vasopressors. One clinical trial (n=78) was too imprecise to yield meaningful results. Two clinical trials are currently ongoing. No study measured long-term quality of life or cognitive function. CONCLUSIONS: Existing data on the effects of vasopressors following traumatic injury are of very low quality according to the Grading of Recommendations, Assessment, Development and Evaluation methodology. With emerging evidence of harm associated with aggressive fluid resuscitation and, in selected subgroups of patients, with permissive hypotension, the alternatives to vasopressor therapy are limited. Observational data showing that vasopressors are part of usual care would provide a strong justification for high-quality clinical trials of early vasopressor use during trauma resuscitation. TRIAL REGISTRATION NUMBER: CRD42016033437.

A systematic review of vasopressor blood pressure targets in critically ill adults with hypotension.

PURPOSE: Clinicians must balance the risks from hypotension with the potential adverse effects of vasopressors. Experts have recommended a mean arterial pressure (MAP) target of at least 65 mmHg, and higher in older patients and in patients with chronic hypertension or atherosclerosis. We conducted a systematic review of randomized-controlled trials comparing higher vs lower blood pressure targets for vasopressor therapy administered to hypotensive critically ill patients. METHODS: We searched MEDLINE®, EMBASE™, and the Cochrane Central Register of Controlled Trials for studies of higher vs lower blood pressure targets for vasopressor therapy in critically ill hypotensive adult patients. Two reviewers independently assessed trial eligibility based on titles and abstracts, and they then selected full-text reports. Outcomes, subgroups, and analyses were prespecified. We used GRADE (Grading of Recommendations Assessment, Development and Evaluation) to rate the overall confidence in the estimates of intervention effects. RESULTS: Of 8001 citations, we retrieved 57 full-text articles and ultimately included two randomized-controlled trials (894 patients). Higher blood pressure targets were not associated with lower mortality (relative risk [RR], 1.05; 95% confidence interval [CI], 0.90 to 1.23; P = 0.54), and neither age (P = 0.17) nor chronic hypertension (P = 0.32) modified the overall effect. Nevertheless, higher blood pressure targets were associated with a greater risk of new-onset supraventricular cardiac arrhythmia (RR, 2.08; 95% CI, 1.28 to 3.38; P < 0.01). CONCLUSION: Current evidence does not support a MAP target > 70 mmHg in hypotensive critically ill adult patients requiring vasopressor therapy.

Vasopressor use following traumatic injury: protocol for a systematic review.

INTRODUCTION: Worldwide, traumatic casualties are projected to exceed 8 million by year 2020. Haemorrhagic shock and brain injury are the leading causes of death following trauma. While intravenous fluids have traditionally been used to support organ perfusion in the setting of haemorrhage, recent investigations have suggested that restricting fluid therapy by tolerating more severe hypotension may improve survival. However, the safety of permissive hypotension remains uncertain, particularly among patients who have suffered a traumatic brain injury. Vasopressors preferentially vasoconstrict blood vessels that supply non-vital organs and capacitance vessels, thereby mobilising the unstressed blood volume. Used as fluid-sparing adjuncts, these drugs can complement resuscitative measures by correcting hypotension without diluting clotting factors or increasing the risk for tissue oedema. METHODS AND ANALYSIS: We will identify randomised control trials comparing early resuscitation with vasopressors versus placebo or standard care in adults following traumatic injury. Data sources will include MEDLINE, EMBASE, CENTRAL, clinical trial registries and conference proceedings. Two reviewers will independently determine trial eligibility. For each included trial, we will conduct duplicate independent data extraction and risk of bias assessment. We will assess the overall quality of the data for each individual outcome using the GRADE approach. ETHICS AND DISSEMINATION: We will report this review in accordance with the PRISMA statement. We will disseminate our findings at critical care and trauma conferences and through a publication in a peer-reviewed journal. We will also use this systematic review to create clinical guidelines (http://www.magicapp.org), which will be disseminated in a standalone publication. TRIAL REGISTRATION NUMBER: CRD42016033437.

Alcohol and Cardiovascular Disease: How Much is Too Much?

PURPOSE OF REVIEW: Previous research suggests that low-moderate alcohol consumption may have cardioprotective effects, while heavy or binge-pattern drinking is harmful. New evidence and research methodology may inform safe thresholds of alcohol use. This review examines recent evidence regarding alcohol's effect on cardiovascular disease, with a special consideration of pattern, drink type, and total quantity. RECENT FINDINGS: New epidemiologic research confirms the potential harmful cardiovascular effects of heavy episodic alcohol use and does not support the previous observation that low-moderate alcohol use protects against stroke. Alcohol consumption also appears to have a continuous positive relationship with the risk of atrial fibrillation. In addition, Mendelian randomization analyses suggest that alcohol may have a direct causal role in adverse cardiovascular effects. Recent studies have confirmed that heavy alcohol use (>14 drinks per week in women and >21 drinks per week in men) and heavy episodic drinking are associated with an increased risk of mortality. New research raises concerns that even low-moderate alcohol use may not offer cardio- or cerebrovascular protection. Drinking ≥3 drinks per day on a regular basis or ≥5 drinks in any one episode should be discouraged.

Attitudes toward the Canadian Guideline for Safe and Effective Use of Opioids for Chronic Non-Cancer Pain: A qualitative study.

BACKGROUND: Chronic noncancer pain (CNCP) refers to all pain disorders, not due to cancer, that persist for ≥3 months. The point prevalence of CNCP in the general population of Western countries is between 19 and 33 percent. Opioids are commonly prescribed for CNCP and are associated with both benefits and harms. The Canadian Guideline for Safe and Effective Use of Opioids for CNCP was published in 2010 to provide guidance for optimal opioid prescribing in patients with CNCP. OBJECTIVES: To investigate the attitudes toward, and use of, the Canadian Opioids Guideline among pain physicians. DESIGN: A qualitative study using one-on-one, semistructured interviews with 12 pain physicians in Ontario, Canada, and thematic analysis of verbatim transcripts. RESULTS: Major themes that emerged from interviews included: (1) generally positive attitudes toward the 2010 Canadian Opioids Guideline, but limited use-half (six of 12) reported they did not use the guideline in practice; (2) strongly contrasting views regarding the 200 mg/d morphine equivalent watchful dose; (3) recognition of gaps in the guideline, especially recommendations for urine drug screening and pain severity-specific therapy; (4) the guideline is excessively long and the format suboptimal; and (5) improved dissemination and education are needed to enhance guideline uptake. CONCLUSIONS: Despite its merits, the Canadian Opioids Guideline suffers from information gaps and from limited uptake, at least in part due to suboptimal format and suboptimal dissemination.