Outpatient metformin use is associated with reduced severity of COVID-19 disease in adults with overweight or obesity

Observational studies suggest outpatient metformin use is associated with reduced mortality from coronavirus disease-2019 (COVID-19). Metformin is known to decrease interleukin-6 and tumor-necrosis factor-α, which appear to contribute to morbidity in COVID-19. We sought to understand whether outpatient metformin use was associated with reduced odds of severe COVID-19 disease in a large US healthcare data set. Retrospective cohort analysis of electronic health record (EHR) data that was pooled across multiple EHR systems from 12 hospitals and 60 primary care clinics in the Midwest between March 4, 2020 and December 4, 2020. Inclusion criteria: data for body mass index (BMI) > 25 kg/m2 and a positive SARS-CoV-2 polymerase chain reaction test; age ≥ 30 and ≤85 years. Exclusion criteria: patient opt-out of research. Metformin is the exposure of interest, and death, admission, and intensive care unit admission are the outcomes of interest. Metformin was associated with a decrease in mortality from COVID-19, OR 0.32 (0.15, 0.66; p = .002), and in the propensity-matched cohorts, OR 0.38 (0.16, 0.91; p = .030). Metformin was associated with a nonsignificant decrease in hospital admission for COVID-19 in the overall cohort, OR 0.78 (0.58-1.04, p = .087). Among the subgroup with a hemoglobin HbA1c available (n = 1193), the adjusted odds of hospitalization (including adjustment for HbA1c) for metformin users was OR 0.75 (0.53-1.06, p = .105). Outpatient metformin use was associated with lower mortality and a trend towards decreased admission for COVID-19. Given metformin's low cost, established safety, and the mounting evidence of reduced severity of COVID-19 disease, metformin should be prospectively assessed for outpatient treatment of COVID-19.

Morbidity and Mortality Trends of Pancreatitis: An Observational Study

Background: Pancreatitis accounts for more than $2.5 billion of healthcare costs and remains the most common gastrointestinal (GI) admission. Few contemporary studies have assessed temporal trends of incidence, complications, management, and outcomes for acute pancreatitis in hospitalized patients at the national level. Methods: We used data from one of the largest hospital-based databases available in the United States, the Healthcare Cost and Utilization Project's (HCUP) State Inpatient Database, from 10 states between 2008 and 2015. We included patients with a diagnosis of acute pancreatitis (ICD-9 CM 577.0). Patient- and hospital-level data were used to estimate incidence and inpatient mortality rates. Results: From 80,736,256 hospitalizations, 929,914 (1.15%) cases of acute pancreatitis were identified, 186,226 (20.2%) of which were caused by gallbladder disease). The median age was 53 years (interquartile range [IQR], 41-67) and 50.8% were men. In-hospital mortality was 2.5% and crude mortality rates declined from 2.9% to 2.0% over the study period. Admission year remained significant after adjusting for patient demographics and comorbidities (odds ratio [OR], 0.90; 95% confidence interval [CI], 0.89-0.90; p < 0.001). Gallbladder disease was associated with decreased odds of mortality (OR, 0.60; 95% CI, 0.57-0.62). Median length of stay was four days (IQR, 2-7) and decreased over time. The rates of surgical and endoscopic interventions were highest in 2011 (peak incidence of 16.1% and 9.5%, respectively) and have been decreasing since. Surgical providers were, on average, more likely than medical providers to perform surgery in both those with and without gallbladder disease etiology (gallbladder disease OR, 7.11; 95% CI, 5.46-9.25; non-gallbladder disease OR, 20.50; 95% CI, 16.81-25.01), endoscopy (gallbladder disease OR, 1.22; 95% CI, 0.87-1.72; non-gallbladder disease OR, 1.60; 95% CI, 1.18-2.16), or both (gallbladder disease OR, 7.00; 95% CI, 5.22-9.37; non-gallbladder disease OR, 8.85; 95% CI, 5.61-13.96). Conclusions: The incidence of pancreatitis, from 2008 to 2015, has increased whereas inpatient mortality (i.e., case fatality) has decreased. Understanding temporal trends in outcomes and management along with provider, hospital, and regional variation can better identify areas for future research and collaboration in managing these patients.

Field-Triage, Hospital-Triage and Triage-Assessment: A Literature Review of the Current Phases of Adult Trauma Triage

ABSTRACT

Despite major improvements in the United States trauma system over the past two decades, prehospital trauma triage is a significant challenge. Undertriage is associated with increased mortality, and overtriage results in significant resource overuse. The American College of Surgeons Committee on Trauma benchmarks for undertriage and overtriage are not being met. Many barriers to appropriate field triage exist, including lack of a formal definition for major trauma, absence of a simple and widely applicable triage mode, and emergency medical service adherence to triage protocols. Modern trauma triage systems should ideally be based on the need for intervention rather than injury severity. Future studies should focus on identifying the ideal definition for major trauma and creating triage models that can be easily deployed. This narrative review article presents challenges and potential solutions for prehospital trauma triage.

Discordant Cardiopulmonary Resuscitation and Code Status at Death

CONTEXT

One fundamental way to honor patient autonomy is to establish and enact their wishes for end-of-life care. Limited research exists regarding adherence with code status.

OBJECTIVES

This study aimed to characterize cardiopulmonary resuscitation (CPR) attempts discordant with documented code status at the time of death in the U.S. and to elucidate potential contributing factors.

METHODS

The Cerner Acute Physiology and Chronic Health Evaluation (APACHE) outcomes database, which includes 237 U.S. hospitals that collect manually abstracted data from all critical care patients, was queried for adults admitted to intensive care units with a documented code status at the time of death from January 2008 to December 2016. The primary outcome was discordant CPR at death. Multivariable logistic regression models were used to identify patient-level and hospital-level associated factors after adjustment for age, hospital, and illness severity (APACHE III score).

RESULTS

A total of 21,537 patients from 56 hospitals were included. Of patients with a do-not-resuscitate code status, 149 (0.8%) received CPR at death, and associated factors included black race, higher APACHE III score, or treatment in small or nonteaching hospitals. Of patients with a full code status, 203 (9.0%) did not receive CPR at death, and associated factors included higher APACHE III score, primary neurologic or trauma diagnosis, or admission in a more recent year.

CONCLUSION

At the time of death, 1.6% of patients received or did not undergo CPR in a manner discordant with their documented code statuses. Race and institutional factors were associated with discordant resuscitation, and addressing these disparities may promote concordant end-of-life care in all patients.

Characterizing COVID-19 clinical phenotypes and associated comorbidities and complication profiles

PURPOSE

Heterogeneity has been observed in outcomes of hospitalized patients with coronavirus disease 2019 (COVID-19). Identification of clinical phenotypes may facilitate tailored therapy and improve outcomes. The purpose of this study is to identify specific clinical phenotypes across COVID-19 patients and compare admission characteristics and outcomes.

METHODS

This is a retrospective analysis of COVID-19 patients from March 7, 2020 to August 25, 2020 at 14 U.S. hospitals. Ensemble clustering was performed on 33 variables collected within 72 hours of admission. Principal component analysis was performed to visualize variable contributions to clustering. Multinomial regression models were fit to compare patient comorbidities across phenotypes. Multivariable models were fit to estimate associations between phenotype and in-hospital complications and clinical outcomes.

RESULTS

The database included 1,022 hospitalized patients with COVID-19. Three clinical phenotypes were identified (I, II, III), with 236 [23.1%] patients in phenotype I, 613 [60%] patients in phenotype II, and 173 [16.9%] patients in phenotype III. Patients with respiratory comorbidities were most commonly phenotype III (p = 0.002), while patients with hematologic, renal, and cardiac (all p<0.001) comorbidities were most commonly phenotype I. Adjusted odds of respiratory, renal, hepatic, metabolic (all p<0.001), and hematological (p = 0.02) complications were highest for phenotype I. Phenotypes I and II were associated with 7.30-fold (HR:7.30, 95% CI:(3.11-17.17), p<0.001) and 2.57-fold (HR:2.57, 95% CI:(1.10-6.00), p = 0.03) increases in hazard of death relative to phenotype III.

CONCLUSION

We identified three clinical COVID-19 phenotypes, reflecting patient populations with different comorbidities, complications, and clinical outcomes. Future research is needed to determine the utility of these phenotypes in clinical practice and trial design.

We Should Do More to Offer Evidence-Based Treatment for an Important Modifiable Risk Factor for COVID-19: Obesity

Observational studies, from multiple countries, repeatedly demonstrate an association between obesity and severe COVID-19, which is defined as need for hospitalization, intensive care unit admission, invasive mechanical ventilation (IMV) or death. Meta-analysis of studies from China, USA, and France show odds ratio (OR) of 2.31 (95% CI 1.3-4.1) for obesity and severe COVID-19. Other studies show OR of 12.1 (95% CI 3.25-45.1) for mortality and OR of 7.36 (95% CI 1.63-33.14) for need for IMV for patients with body mass index (BMI) ≥ 35 kg/m². Obesity is the only modifiable risk factor that is not routinely treated but treatment can lead to improvement in visceral adiposity, insulin sensitivity, and mortality risk. Increasing the awareness of the association between obesity and COVID-19 risk in the general population and medical community may serve as the impetus to make obesity identification and management a higher priority.

Bowel Ischemia Score Predicts Early Operation in Patients With Adhesive Small Bowel Obstruction

BACKGROUND

Nonoperative management of adhesive small bowel obstruction (SBO) is successful in up to 80% of patients. Current recommendations advocate for computed tomography (CT) scan in all patients with SBO to supplement surgical decision-making. The hypothesis of this study was that cumulative findings on CT would predict the need for operative intervention in the setting of SBO.

METHODS

This is an analysis of a retrospectively and prospectively collected adhesive SBO database over a 6-year period. A Bowel Ischemia Score (BIS) was developed based on the Eastern Association for the Surgery of Trauma guidelines of CT findings suggestive of bowel ischemia. One point was assigned for each of the six variables. Early operation was defined as surgery within 6 hours of CT scan.

RESULTS

Of the 275 patients in the database, 249 (90.5%) underwent CT scan. The operative rate was 28.3% with a median time from CT to operation of 21 hours (Interquartile range 5.2-59.2 hours). Most patients (166/217, 76.4%) with a BIS of 0 or 1 were successfully managed nonoperatively, whereas the majority of those with a BIS of 3 required operative intervention (5/6, 83.3%). The discrimination (area under the receiver operating characteristic curve) of BIS for early surgery, any operative intervention, and small bowel resection were 0.83, 0.72, and 0.61, respectively.

CONCLUSION

The cumulative signs of bowel ischemia on CT scan represented by BIS, rather than the presence or absence of any one finding, correlate with the need for early operative intervention.

The Effect of Organ System Surgery on Intensive Care Unit Mortality in a Cohort of Critically Ill Surgical Patients

BACKGROUND

The critical illness burden in the United States is growing with an aging population obtaining surgical intervention despite age-related comorbidities. The effect of organ system surgical intervention on intensive care units (ICUs) mortality is unknown.

METHODS

We performed an 8-year retrospective analysis of surgical ICU patients. Poisson regression analysis was performed assessing the relative risk of in-hospital mortality based on surgical intervention.

RESULTS

Of 468 000 ICU patients included, 97 968 (20.9%) were surgical admissions and 97 859 (99.9%) had complete outcomes data. Nonsurvivors were older (68.8 ± 15.4 vs. 62.7 ± 15.8 years, P < .001) with higher Acute Physiology, Age, Chronic Health Evaluation (APACHE) III Scores (81.4 ± 33.6 vs. 46.7 ± 20.1, P < .001. Patients with gastrointestinal (GI) (n = 1,558, 7.8%), musculoskeletal (n = 277, 5.5%), and neurological (n = 884, 4.6%) system operations had the highest mortality. Upon Poisson regression model, patients undergoing emergent operative interventions on the neurologic system (RR 1.86, 95% CI 1.67-2.07, P < .001) had increased relative risk of mortality when compared to emergent operative interventions on the cardiovascular system after controlling for pertinent covariates. Elective operative interventions on the respiratory (RR 2.39, 95% CI 2.03-2.80, P < .001), GI (RR 2.34, 95% CI 2.10-2.61, P < .001), and skin and soft tissue (RR 2.26, 95% CI 1.77-2.89, P < .001) systems had increased risk of mortality when compared to elective cardiovascular system surgery after controlling for pertinent covariates.

CONCLUSION

We found significant differences in the risk of mortality based on organ system of operative intervention. The prognostication of critically ill patients undergoing surgical intervention is currently not accounted for in prognostic scoring systems.

mTOR inhibition in COVID-19: A commentary and review of efficacy in RNA viruses

In this commentary, we shed light on the role of the mammalian target of rapamycin (mTOR) pathway in viral infections. The mTOR pathway has been demonstrated to be modulated in numerous RNA viruses. Frequently, inhibiting mTOR results in suppression of virus growth and replication. Recent evidence points towards modulation of mTOR in severe acute respiratory syndrome coronavirus 2 (SARS-CoV-2) infection. We discuss the current literature on mTOR in SARS-CoV-2 and highlight evidence in support of a role for mTOR inhibitors in the treatment of coronavirus disease 2019.

Racial/Ethnic Disparities in Hospital Admissions from COVID-19 and Determining the Impact of Neighborhood Deprivation and Primary Language

Background Despite past and ongoing efforts to achieve health equity in the United States, persistent disparities in socioeconomic status along with multilevel racism maintain disparate outcomes and appear to be amplified by COVID-19. Objective Measure socioeconomic factors and primary language effects on the risk of COVID-19 severity across and within racial/ethnic groups. Design Retrospective cohort study. Setting Health records of 12 Midwest hospitals and 60 clinics in the U.S. between March 4, 2020 to August 19, 2020. Patients PCR+ COVID-19 patients. Exposures Main exposures included race/ethnicity, area deprivation index (ADI), and primary language. Main Outcomes and Measures The primary outcome was COVID-19 severity using hospitalization within 45 days of diagnosis. Logistic and competing-risk regression models (censored at 45 days and accounting for the competing risk of death prior to hospitalization) assessed the effects of neighborhood-level deprivation (using the ADI) and primary language. Within race effects of ADI and primary language were measured using logistic regression. Results 5,577 COVID-19 patients were included, 866 (n=15.5%) were hospitalized within 45 days of diagnosis. Hospitalized patients were older (60.9 vs. 40.4 years, p<0.001) and more likely to be male (n=425 [49.1%] vs. 2,049 [43.5%], p=0.002). Of those requiring hospitalization, 43.9% (n=381), 19.9% (n=172), 18.6% (n=161), and 11.8% (n=102) were White, Black, Asian, and Hispanic, respectively. Independent of ADI, minority race/ethnicity was associated with COVID-19 severity; Hispanic patients (OR 3.8, 95% CI 2.72-5.30), Asians (OR 2.39, 95% CI 1.74-3.29), and Blacks (OR 1.50, 95% CI 1.15-1.94). ADI was not associated with hospitalization. Non-English speaking (OR 1.91, 95% CI 1.51-2.43) significantly increased odds of hospital admission across and within minority groups. Conclusions Minority populations have increased odds of severe COVID-19 independent of neighborhood deprivation, a commonly suspected driver of disparate outcomes. Non-English-speaking accounts for differences across and within minority populations. These results support the continued concern that racism contributes to disparities during COVID-19 while also highlighting the underappreciated role primary language plays in COVID-19 severity across and within minority groups.

Racial Disparities at Mixed-Race and Minority Hospitals : Treatment of African American Males With High-Grade Splenic Injuries

INTRODUCTION

Racial and socioeconomic disparities in health access and outcomes for many conditions is well known. However, for time-sensitive high-acuity diseases such as traumatic injuries, disparities in access and outcomes should be significantly diminished. Our primary objective was to characterize racial disparities across majority, mixed-race, and minority hospitals for African American ([AA] vs White) males with high-grade splenic injuries.

METHODS

Data from the National Trauma Data Bank were utilized from 2007 to 2015; 24 855 AA or White males with high-grade splenic injuries were included. Multilevel mixed-effects regression analysis was used to evaluate disparities in outcomes and resource allocation.

RESULTS

Mortality was significantly higher for AA males at mixed-race (OR 1.6; 95% CI 1.3-2.1; P < .001) and minority (OR 2.1; 95% CI 1.5-3.0; P < .001) hospitals, but not at majority hospitals. At minority hospitals, AA males were significantly less likely to be admitted to the intensive care unit (OR 0.7; 95% CI, 0.49-0.97; P = .04) and experienced a significantly longer time to surgery (IRR 1.5; P = .02). Minority hospitals were significantly more likely to have failures from angiographic embolization requiring operative intervention (OR 2.2, P = .009). At both types of nonmajority hospitals, AA males with penetrating injuries were more likely to be managed with angiography (mixed-race hospitals: OR 1.7; P = .046 vs minority hospitals: OR 1.6; P = .08).

DISCUSSION

While multiple studies have shown that minority hospitals have increased mortality compared to majority hospitals, this study found this disparity only existed for AAs.

Characterizing COVID-19 Clinical Phenotypes and Associated Comorbidities and Complication Profiles

BACKGROUND

There is limited understanding of heterogeneity in outcomes across hospitalized patients with coronavirus disease 2019 (COVID-19). Identification of distinct clinical phenotypes may facilitate tailored therapy and improve outcomes.

OBJECTIVE

Identify specific clinical phenotypes across COVID-19 patients and compare admission characteristics and outcomes.

DESIGN, SETTINGS, AND PARTICIPANTS

Retrospective analysis of 1,022 COVID-19 patient admissions from 14 Midwest U.S. hospitals between March 7, 2020 and August 25, 2020.

METHODS

Ensemble clustering was performed on a set of 33 vitals and labs variables collected within 72 hours of admission. K-means based consensus clustering was used to identify three clinical phenotypes. Principal component analysis was performed on the average covariance matrix of all imputed datasets to visualize clustering and variable relationships. Multinomial regression models were fit to further compare patient comorbidities across phenotype classification. Multivariable models were fit to estimate the association between phenotype and in-hospital complications and clinical outcomes. Main outcomes and measures: Phenotype classification (I, II, III), patient characteristics associated with phenotype assignment, in-hospital complications, and clinical outcomes including ICU admission, need for mechanical ventilation, hospital length of stay, and mortality.

RESULTS

The database included 1,022 patients requiring hospital admission with COVID-19 (median age, 62.1 [IQR: 45.9-75.8] years; 481 [48.6%] male, 412 [40.3%] required ICU admission, 437 [46.7%] were white). Three clinical phenotypes were identified (I, II, III); 236 [23.1%] patients had phenotype I, 613 [60%] patients had phenotype II, and 173 [16.9%] patients had phenotype III. When grouping comorbidities by organ system, patients with respiratory comorbidities were most commonly characterized by phenotype III (p=0.002), while patients with hematologic (p<0.001), renal (p<0.001), and cardiac (p<0.001) comorbidities were most commonly characterized by phenotype I. The adjusted odds of respiratory (p<0.001), renal (p<0.001), and metabolic (p<0.001) complications were highest for patients with phenotype I, followed by phenotype II. Patients with phenotype I had a far greater odds of hepatic (p<0.001) and hematological (p=0.02) complications than the other two phenotypes. Phenotypes I and II were associated with 7.30-fold (HR: 7.30, 95% CI: (3.11-17.17), p<0.001) and 2.57-fold (HR: 2.57, 95% CI: (1.10-6.00), p=0.03) increases in the hazard of death, respectively, when compared to phenotype III.

CONCLUSION

In this retrospective analysis of patients with COVID-19, three clinical phenotypes were identified. Future research is urgently needed to determine the utility of these phenotypes in clinical practice and trial design.

Non-alcoholic fatty liver disease (NAFLD) and risk of hospitalization for Covid-19

Background

Covid-19 disease causes significant morbidity and mortality through increase inflammation and thrombosis. Non-alcoholic fatty liver disease and non-alcoholic steatohepatitis are states of chronic inflammation and indicate advanced metabolic disease. We sought to understand the risk of hospitalization for Covid-19 associated with NAFLD/NASH.

Methods

Retrospective analysis of electronic medical record data of 6,700 adults with a positive SARS-CoV-2 PCR from March 1, 2020 to Aug 25, 2020. Logistic regression and competing risk were used to assess odds of being hospitalized. Additional adjustment was added to assess risk of hospitalization among patients with a prescription for metformin use within the 3 months prior to the SARS-CoV-2 PCR result, history of home glucagon-like-peptide 1 receptor agonist (GLP-1 RA) use, and history of metabolic and bariatric surgery (MBS). Interactions were assessed by gender and race.

Results

A history of NAFLD/NASH was associated with increased odds of admission for Covid-19: logistic regression OR 2.04 (1.55, 2.96, p<0.01), competing risks OR 1.43 (1.09-1.88, p<0.01); and each additional year of having NAFLD/NASH was associated with a significant increased risk of being hospitalized for Covid-19, OR 1.86 (1.43-2.42, p<0.01). After controlling for NAFLD/NASH, persons with obesity had decreased odds of hospitalization for Covid-19, OR 0.41 (0.34-0.49, p<0.01). NAFLD/NASH increased risk of hospitalization in men and women, and in all racial/ethnic subgroups. Mediation treatments for metabolic syndrome were associated with non-significant reduced risk of admission: OR 0.42 (0.18-1.01, p=0.05) for home metformin use and OR 0.40 (0.14-1.17, p=0.10) for home GLP-1RA use. MBS was associated with a significant decreased risk of admission: OR 0.22 (0.05-0.98, p<0.05).

Conclusions

NAFLD/NASH is a significant risk factor for hospitalization for Covid-19, and appears to account for risk attributed to obesity. Treatments for metabolic disease mitigated risks from NAFLD/NASH. More research is needed to confirm risk associated with visceral adiposity, and patients should be screened for and informed of treatments for metabolic syndrome.

Racial Disparities at Mixed-Race and Minority Hospitals: Treatment of African American Males With High-Grade Splenic Injuries

INTRODUCTION

Racial and socioeconomic disparities in health access and outcomes for many conditions are well known. However, for time-sensitive high-acuity diseases such as traumatic injuries, disparities in access and outcomes should be significantly diminished. Our primary objective was to characterize racial disparities across majority, mixed-race, and minority hospitals for African American (AA) versus white males with high-grade splenic injuries.

METHODS

Data from the National Trauma Data Bank was utilized from 2007 to 2015. A total of 24 855 AA or white males with high-grade splenic injuries were included. Multilevel mixed effects regression analysis was used to evaluate disparities in outcomes and resource allocation.

RESULTS

Mortality was significantly higher for AA males at mixed-race (odds ratio [OR] 1.6; 95% CI 1.3-2.1; P < .001) and minority (OR 2.1; 95% CI 1.5-3.0; P < .001) hospitals, but not at majority hospitals. At minority hospitals, AA males were significantly less likely to be admitted to the intensive care unit (OR 0.7; 95% CI 0.49-0.97; P = .04) and experienced a significantly longer time to surgery (IRR 1.5; P = .02). Minority hospitals were significantly more likely to have failures from angiographic embolization requiring operative intervention (OR 2.2; P = .009). At both types of nonmajority hospitals, AA males with penetrating injuries were more likely to be managed with angiography (mixed-race hospitals: OR 1.7; P = .046 vs minority hospitals: OR 1.6; P = .08).

DISCUSSION

While multiple studies have shown that minority hospitals have increased mortality compared to majority hospitals, this study found this disparity only existed for AAs.

Understanding the renin-angiotensin-aldosterone-SARS-CoV axis: a comprehensive review

Importance

Coronavirus disease 2019 (COVID-19), the disease caused by the severe acute respiratory syndrome coronavirus 2 (SARS-CoV-2), has been declared a global pandemic with significant morbidity and mortality since first appearing in Wuhan, China, in late 2019. As many countries are grappling with the onset of their epidemics, pharmacotherapeutics remain lacking. The window of opportunity to mitigate downstream morbidity and mortality is narrow but remains open. The renin–angiotensin–aldosterone system (RAAS) is crucial to the homeostasis of both the cardiovascular and respiratory systems. Importantly, SARS-CoV-2 utilises and interrupts this pathway directly, which could be described as the renin–angiotensin–aldosterone–SARS-CoV (RAAS–SCoV) axis. There exists significant controversy and confusion surrounding how anti-hypertensive agents might function along this pathway. This review explores the current state of knowledge regarding the RAAS–SCoV axis (informed by prior studies of SARS-CoV), how this relates to our currently evolving pandemic, and how these insights might guide our next steps in an evidence-based manner.

Observations

This review discusses the role of the RAAS–SCoV axis in acute lung injury and the effects, risks and benefits of pharmacological modification of this axis. There may be an opportunity to leverage the different aspects of RAAS inhibitors to mitigate indirect viral-induced lung injury. Concerns have been raised that such modulation might exacerbate the disease. While relevant preclinical, experimental models to date favour a protective effect of RAAS–SCoV axis inhibition on both lung injury and survival, clinical data related to the role of RAAS modulation in the setting of SARS-CoV-2 remain limited.

Conclusion

Proposed interventions for SARS-CoV-2 predominantly focus on viral microbiology and aim to inhibit viral cellular injury. While these therapies are promising, immediate use may not be feasible, and the time window of their efficacy remains a major unanswered question. An alternative approach is the modulation of the specific downstream pathophysiological effects caused by the virus that lead to morbidity and mortality. We propose a preponderance of evidence that supports clinical equipoise regarding the efficacy of RAAS-based interventions, and the imminent need for a multisite randomised controlled clinical trial to evaluate the inhibition of the RAAS–SCoV axis on acute lung injury in COVID-19.

The interplay of SARS-CoV-2 with the renin–angiotensin–aldosterone system probably accounts for much of its unique pathology. Appreciating the degree and mechanism of this interaction highlights potential therapeutic options, including blockade (ARBs).https://bit.ly/3aue4tS

Observational Study of Metformin and Risk of Mortality in Patients Hospitalized with Covid-19

Background Type 2 diabetes (T2DM) and obesity are significant risks for mortality in Covid19. Metformin has been hypothesized as a treatment for COVID19. Metformin has sex specific immunomodulatory effects which may elucidate treatment mechanisms in COVID-19. In this study we sought to identify whether metformin reduced mortality from Covid19 and if sex specific interactions exist. Methods De-identified claims data from UnitedHealth were used to identify persons with at least 6 months continuous coverage who were hospitalized with Covid-19. Persons in the metformin group had at least 90 days of metformin claims in the 12 months before hospitalization. Unadjusted and multivariate models were conducted to assess risk of mortality based on metformin as a home medication in individuals with T2DM and obesity, controlling for pre-morbid conditions, medications, demographics, and state. Heterogeneity of effect was assessed by sex. Results 6,256 persons were included; 52.8% female; mean age 75 years. Metformin was associated with decreased mortality in women by logistic regression, OR 0.792 (0.640, 0.979); mixed effects OR 0.780 (0.631, 0.965); Cox proportional-hazards: HR 0.785 (0.650, 0.951); and propensity matching, OR of 0.759 (0.601, 0.960). TNF-alpha inhibitors were associated with decreased mortality in the 38 persons taking them, by propensity matching, OR 0.19 (0.0378, 0.983). Conclusions Metformin was significantly associated with reduced mortality in women with obesity or T2DM in observational analyses of claims data from individuals hospitalized with Covid-19. This sex-specific finding is consistent with metformin reducing TNF-alpha in females over males, and suggests that metformin conveys protection in Covid-19 through TNF-alpha effects. Prospective studies are needed to understand mechanism and causality.

Predictors of Change in Code Status from Time of Admission to Death in Critically Ill Surgical Patients

Racial and gender disparities in end-of-life decision-making practices have not been well described in surgical patients. We performed an eight-year retrospective analysis of surgical patients within the Cerner Acute Physiology and Chronic Health Evaluation Outcomes database. ICU patients with documented admission code status, and death or ICU discharge code status, respectively, were included. Logistic regression analysis was performed to assess change in code status. Of 468,000 ICU patients, 97,968 (20.9%) were surgical, 63,567 (95%) survived, and 3,343 (5%) died during their hospitalization. Of those, 50,915 (80.1%) and 2,625 (78.5%) had complete code status data on admission and discharge or death, respectively. Women were less likely than men to remain full code at ICU discharge and death (n = 20,940, 95.6% and n = 141, 11.9% vs n = 29,320, 97.4% and n = 233, 16.3%, P < 0.001). Compared with whites, blacks and other minorities had a 0.46 odds (95% confidence interval [CI]: 0.33–0.64, P < 0.001) and 0.54 odds (95% CI: 0.34–0.85, P = 0.01) of changing from full code status before death, respectively. Before ICU discharge, blacks and other minorities had a 0.56 odds of changing from full code status when compared with whites (95% CI: 0.40–0.79, P < 0.001 vs 95% CI: 0.36–0.87, P = 0.01, respectively). Women were more likely to be discharged or die after a change in code status from full code (odds ratio 1.27, 95% CI: 1.06–1.07, P < 0.001; odds ratio 1.39, 95% CI: 1.09–1.79, P = 0.009). Men and minorities are more likely to be discharged from the ICU or die with a full code status designation.

Association Between Adherence to Evidence-Based Practices for Treatment of Patients With Traumatic Rib Fractures and Mortality Rates Among US Trauma Centers

IMPORTANCE

Rib fractures are sustained by nearly 15% of patients who experience trauma and are associated with significant morbidity and mortality. Evidence-based practice (EBP) rib fracture management guidelines and treatment algorithms have been published. However, few studies have evaluated trauma center adherence to EBP or the clinical outcomes of each practice within a national cohort.

OBJECTIVE

To examine adherence to 6 EBPs for rib fractures across US trauma centers and the association with in-hospital mortality.

DESIGN, SETTING, AND PARTICIPANTS

A retrospective cohort study was conducted from January 1, 2007, to December 31, 2014, of 777 US trauma centers participating in the National Trauma Data Bank. A total of 625 617 patients (age, ≥16 years) were evaluated. Patients without rib fractures and those with no signs of life or institutions with poor data quality were excluded. Data analysis was performed from January 1, 2007, to December 31, 2014.

MAIN OUTCOMES AND MEASURES

Six EBPs were defined: (1) neuraxial blockade, (2) intensive care unit admission, (3) pneumatic stabilization, (4) chest computed tomographic scans for older adults (≥65 years) with 3 or more rib fractures, (5) surgical rib fixation for flail chest, and (6) tube thoracostomy placement for hemothorax and/or pneumothorax. Multiple imputation was used to account for missing data. Patients were propensity score matched in a 1:1 fashion based on demographic characteristics; injury severity parameters, including the Injury Severity Score (range, 0-75; higher scores indicate more severe injuries); and comorbidities. Logistic regression was used to determine the association of each practice with all-cause in-hospital mortality.

RESULTS

Of the 625 617 patients with rib fractures included in this analysis, 456 196 patients (73%) were white and 432 229 patients (69%) were male; the median age of the patients was 51 (interquartile range, 37-65) years, and the mean (SD) Injury Severity Score was 18.3 (11.1). The mean (SD) number of rib fractures was 4.2 (2.6). On univariate analysis, patients treated at verified level I trauma centers were more likely to receive 5 or 6 EBPs (all but pneumatic stabilization). Of those who met eligibility, only 4578 of 111 589 patients (4%) received neuraxial blockade, 46 456 of 111 589 patients (42%) were admitted to the intensive care unit, 3302 of 24 319 patients (14%) received surgical rib fixation, 1240 of 111 589 patients (1%) received pneumatic stabilization, 109 160 of 258 334 patients (42%) received tube thoracostomy, and 32 405 of 81 417 patients (40%) received chest computed tomographic scans. Three EBPs were associated with decreased mortality: neuraxial blockade (odds ratio [OR], 0.64; 95% CI, 0.51-0.79; P < .001) for patients aged 65 years or older with 3 or more rib fractures, surgical rib fixation (OR, 0.13; 95% CI, 0.01-0.18; P < .001), and intensive care unit admission (OR, 0.93; 95% CI, 0.86-1.00; P = .04) for patients aged 65 years or older with 3 or more rib fractures. Pneumatic stabilization (OR, 1.71; 95% CI, 1.25-2.35; P < .001) and chest tube placement (OR, 1.27; 95% CI, 1.21-1.33; P < .001) were associated with increased mortality in older patients with 3 or more rib fractures. On multivariable analysis, insurance status, race/ethnicity, injury severity, hospital bed size, and trauma center verification level were associated with receiving EBPs for rib fractures.

CONCLUSIONS AND RELEVANCE

Significant variation appears to exist in the delivery of EBPs for rib fractures across US trauma centers. Three EBPs were associated with reduced mortality, but EBP adherence was poor. Multiple factors, including trauma center verification level, appear to be associated with patients receiving EBPs for rib fractures.

Predictors of Change in Code Status from Time of Admission to Death in Critically Ill Surgical Patients

Racial and gender disparities in end-of-life decision-making practices have not been well described in surgical patients. We performed an eight-year retrospective analysis of surgical patients within the Cerner Acute Physiology and Chronic Health Evaluation Outcomes database. ICU patients with documented admission code status, and death or ICU discharge code status, respectively, were included. Logistic regression analysis was performed to assess change in code status. Of 468,000 ICU patients, 97,968 (20.9%) were surgical, 63,567 (95%) survived, and 3,343 (5%) died during their hospitalization. Of those, 50,915 (80.1%) and 2,625 (78.5%) had complete code status data on admission and discharge or death, respectively. Women were less likely than men to remain full code at ICU discharge and death (n = 20,940, 95.6% and n = 141, 11.9% vs n = 29,320, 97.4% and n = 233, 16.3%, P < 0.001). Compared with whites, blacks and other minorities had a 0.46 odds (95% confidence interval [CI]: 0.33-0.64, P < 0.001) and 0.54 odds (95% CI: 0.34-0.85, P = 0.01) of changing from full code status before death, respectively. Before ICU discharge, blacks and other minorities had a 0.56 odds of changing from full code status when compared with whites (95% CI: 0.40-0.79, P < 0.001 vs 95% CI: 0.36-0.87, P = 0.01, respectively). Women were more likely to be discharged or die after a change in code status from full code (odds ratio 1.27, 95% CI: 1.06-1.07, P < 0.001; odds ratio 1.39, 95% CI: 1.09-1.79, P = 0.009). Men and minorities are more likely to be discharged from the ICU or die with a full code status designation.

Implementation of a Prophylactic Anticoagulation Guideline for Patients with Traumatic Brain Injury

BACKGROUND

Patients with traumatic brain injury (TBI) are at an increased risk of developing complications from venous thromboembolisms (VTEs [blood clots]). Benchmarking by the American College of Surgeons Trauma Quality Improvement Program identified suboptimal use of prophylactic anticoagulation in patients with TBI. We hypothesized that institutional implementation of an anticoagulation protocol would improve clinical outcomes in such patients.

METHODS

A new prophylactic anticoagulation protocol that incorporated education, weekly audits, and real-time adherence feedback was implemented in July 2015. The trauma registry identified patients with TBI before (PRE) and after (POST) implementation. Multivariable regression analysis with risk adjustment was used to compare use of prophylactic anticoagulation, VTE events, and mortality.

RESULTS

A total of 681 patients with TBI (368 PRE, 313 POST) were identified. After implementation of the VTE protocol, more patients received anticoagulation (PRE: 39.4%, POST: 80.5%, p < 0.001), time to initiation was shorter (PRE: 140 hours, POST: 59 hours, p < 0.001), and there were fewer VTE events (PRE: 19 [5.2%], POST: 7 [2.2%], p = 0.047). Multivariable analysis showed that POST patients were more likely to receive anticoagulation (odds ratio [OR] = 10.8, 95% confidence interval [CI] = 6.9-16.7, p < 0.001) and less likely to develop VTE (OR = 0.33, 95% CI = 0.1-1.0, p = 0.05).

CONCLUSION

Benchmarking can assist institutions to identity potential clinically relevant areas for quality improvement in real time. Combining education and multifaceted protocol implementation can help organizations to better focus limited quality resources and counteract barriers that have hindered adoption of best practices.

Pre- and Peri-Operative Factors Associated with Chronic Critical Illness in Liver Transplant Recipients

Background: Chronic critical illness (CCI) is a new and increasing entity that accounts for substantial cost despite its low incidence. We hypothesized that patients with end-stage liver failure undergoing liver transplant would be at high risk for developing CCI. With limited liver donors it is essential to understand pre- and peritransplant predictors of CCI. Methods: To accomplish this we performed a retrospective cohort study at a large academic transplant center of all adult liver transplant patients from 2011 to 2017. We defined CCI as the need for mechanical ventilation for seven days or more post-transplant. Recipients who had re-transplantation during their index admission, acute rejection, or who died during transplant surgery were excluded. Logistic regression was performed using the Akaike information criterion (AIC) and the likelihood ratio test. Results: We identified 382 transplant recipients. Forty-five (11.8%) developed CCI. Univariable analysis identified 16 pre-transplant factors associated with post-transplant CCI. Subsequent multivariable logistic regression identified eight independent factors associated with CCI in liver transplant recipients including previous liver transplant, acute renal failure, frailty, lower albumin level, higher international normalized ratio, need for mechanical ventilation, and higher systolic pulmonary artery pressure. Pre-transplant factors associated with protection against CCI included higher Model for End-Stage Liver Disease (MELD) score. Conclusion: The incidence of CCI post-liver transplant is similar to the general population admitted to the intensive care unit. Pre-transplant factors associated with CCI can help identify at-risk patients, and furthermore, promote further research and interventions with the goal to decrease the incidence of CCI in the liver transplant recipients.

Named Entity Recognition in Prehospital Trauma Care

Natural language processing (NLP) methods would improve outcomes in the area of prehospital Emergency Medical Services (EMS) data collection and abstraction. This study evaluated off-the-shelf solutions for automating labelling of clinically relevant data from EMS reports. A qualitative approach for choosing the best possible ensemble of pretrained NLP systems was developed and validated along with a feature using word embeddings to test phrase synonymy. The ensemble showed increased performance over individual systems.

Should they stay or should they go? Who benefits from interfacility transfer to a higher-level trauma center following initial presentation at a lower-level trauma center

BACKGROUND

Interfacility transfer of patients from Level III/IV to Level I/II (tertiary) trauma centers has been associated with improved outcomes. However, little data are available classifying the specific subsets of patients that derive maximal benefit from transfer to a tertiary trauma center. Drawbacks to transfer include increased secondary overtriage. Here, we ask which injury patterns are associated with improved survival following interfacility transfer.

METHODS

Data from the National Trauma Data Bank was utilized. Inclusion criteria were adults (≥16 years). Patients with Injury Severity Score of 10 or less or those who arrived with no signs of life were excluded. Patients were divided into two cohorts: those admitted to a Level III/IV trauma center versus those transferred into a tertiary trauma center. Multiple imputation was performed for missing values, and propensity scores were generated based on demographics, injury patterns, and disease severity. Using propensity score-stratified Cox proportional hazards regression, the hazard ratio for time to death was estimated.

RESULTS

Twelve thousand five hundred thirty-four (5.2%) were admitted to Level III/IV trauma centers, and 227,315 (94.8%) were transferred to a tertiary trauma center. Patients transferred to a tertiary trauma center had reduced mortality (hazard ratio, 0.69; p < 0.001). We identified that patients with traumatic brain injury with Glasgow Coma Scale score less than 13, pelvic fracture, penetrating mechanism, solid organ injury, great vessel injury, respiratory distress, and tachycardia benefited from interfacility transfer to a tertiary trauma center. In this sample, 56.8% of the patients benefitted from transfer. Among those not transferred, 49.5% would have benefited from being transferred.

CONCLUSION

Interfacility transfer is associated with a survival benefit for specific patients. These data support implementation of minimum evidence-based criteria for interfacility transfer.

LEVEL OF EVIDENCE

Therapeutic/Care Management, Level IV.

Utilization of Intensive Care Unit Nutrition Consultation Is Associated With Reduced Mortality

BACKGROUND

The aim of this project was to investigate the prevalence of nutrition consultation (NC) in U.S. intensive care units (ICUs) and to examine its association with patient outcomes.

METHODS

Data from the Healthcare Cost and Utilization Project's state inpatient databases was utilized from 2010 - 2014. A multilevel logistic regression model was used to evaluate the relationship between NC and clinical outcomes.

RESULTS

Institutional ICU NC rates varied significantly (mean: 14%, range: 0.1%-73%). Significant variation among underlying disease processes was identified, with burn patients having the highest consult rate (P < 0.001, mean: 6%, range: 2%-25%). ICU patients who received NC had significantly lower in-hospital mortality (odds ratio [OR] 0.59, 95% confidence interval [CI] 0.48-0.74, P < 0.001), as did the subset with malnutrition (OR 0.72, 95% CI 0.53-0.99, P = 0.047) and the subset with concomitant physical therapy consultation (OR 0.53, 95% CI 0.38-0.74, P < 0.001). NC was associated with significantly lower rates of intubation, pulmonary failure, pneumonia, and gastrointestinal bleeding (P < 0.05). Furthermore, patients who received NC were more likely to receive enteral or parenteral nutrition (ENPN) (OR 1.8, 95% CI 1.4-2.3, P < 0.001). Patients who received follow-up NC were even more likely to receive ENPN (OR 3.0, 95% CI 2.1-4.2, P < 0.001).

CONCLUSIONS

Rates of NC were low in critically ill patients. This study suggests that increased utilization of NC in critically ill patients may be associated with improved clinical outcomes.

Nationwide cohort study of independent risk factors for acute respiratory distress syndrome after trauma

Background

The primary objective of this study was to evaluate the effect of specific direct and indirect factors that accounted, in trauma patients, for the development of acute respiratory distress syndrome (ARDS) and mortality in patients with ARDS.

Methods

We performed a retrospective cohort study of patients from the National Trauma Data Bank. Multilevel mixed-effects logistic regression was used with the development of ARDS as the primary and mortality in patients with ARDS as the secondary outcome measures. We compared trauma patients with versus without thoracic (direct) and extrathoracic (indirect) risk factors, using patient demographics, physiologic, and anatomic injury severity as covariates. Subset analysis was performed for patients with trauma-induced lung contusion (TILC) and for patients with minor (Injury Severity Score [ISS] ≤15) injury.

Results

A total of 2 998 964 patients were studied, of whom 28 597 developed ARDS. From 2011 to 2014, the incidence of ARDS decreased; however, mortality in patients with ARDS has increased. Predictors of ARDS included direct thoracic injury (TILC, multiple rib fractures, and flail chest), as well as indirect factors (increased age, male gender, higher ISS, lower Glasgow Coma Scale motor component score, history of cardiopulmonary or hematologic disease, and history of alcoholism or obesity). Patients with ARDS secondary to direct thoracic injury had a lower risk of mortality compared with patients with ARDS due to other mechanisms.

Discussion

Despite the decreasing incidence of trauma-induced ARDS, mortality in patients with ARDS has increased. Direct thoracic injury was the strongest predictor of ARDS. Knowing specific contributors to trauma-induced ARDS could help identify at-risk patients early in their hospitalization and mitigate the progression to ARDS and thereby mortality.

Level of evidence

Prognostic study, level III.

Empirical systemic anticoagulation is associated with decreased venous thromboembolism in critically ill influenza A H1N1 acute respiratory distress syndrome patients

BACKGROUND

An association between increased venous thromboembolism (VTE) events and influenza A H1N1 (H1N1) was noted in the first 10 patients with severe acute respiratory distress syndrome (ARDS). An empirical systemic anticoagulation protocol (heparin intravenous infusion) was initiated when autopsy of patients with severe hypoxemia confirmed multiple primary pulmonary thrombi and emboli. The purpose of this study was to examine the relationship between H1N1 and VTE events and to assess the efficacy of empirical systemic heparin anticoagulation in preventing VTE and death in H1N1 severe ARDS patients.

METHODS

An observational cohort study of critically ill severe ARDS patients with possible H1N1 viral pneumonia was performed in a surgical intensive care unit in a single 990-bed academic tertiary care center. Early empirical systemic heparin anticoagulation for all severe ARDS patients with possible H1N1 viral pneumonia was initiated as a VTE preventive strategy.

RESULTS

Univariate comparisons and multivariate logistic regression were used to identify risk factors for VTE. Independent risk factors for VTE included H1N1, culture-positive bacterial pneumonia, and vasopressor requirement. Independent risk factors for pulmonary embolism included H1N1, culture-positive bacterial pneumonia, and male sex. H1N1 ARDS patients had 23.3-fold higher risk for pulmonary embolism and 17.9-fold increased risk for VTE. Kaplan-Meier analysis and log-rank test confirmed that empirical systemic heparin anticoagulation provided significant protection from thrombotic events in the H1N1-positive but not in the H1N1-negative critically ill ARDs patients. In multivariate analysis, adjusting for H1N1 status, patients without empirical systemic anticoagulation were 33 times more likely to have any VTE compared with those treated with empirical systemic heparin anticoagulation (P = .01).

CONCLUSIONS

Critically ill patients with H1N1 ARDS have increased risk of venous thrombotic complications, particularly pulmonary thromboembolism. Empirical systemic heparin anticoagulation in this cohort of patients significantly reduced VTE incidence without increased hemorrhagic complications.

Outcomes of Acute Kidney Injury in Patients With Severe ARDS Due to Influenza A(H1N1) pdm09 Virus

BACKGROUND

The incidence and long-term outcomes of acute kidney injury in patients with severe acute respiratory distress syndrome (ARDS) due to influenza A(H1N1) pdm09 virus (pH1N1) have not been examined.

OBJECTIVE

To assess long-term renal recovery in patients with acute kidney injury and severe ARDS due to pH1N1.

METHODS

A retrospective observational cohort study of adults with severe pH1N1-associated ARDS admitted to a tertiary referral center. Baseline characteristics, acute kidney injury stage, continuous renal replacement therapy (CRRT), intermittent hemodialysis, extracorporeal membrane oxygenation, survival, and renal recovery (defined as dialysis independence) were evaluated.

RESULTS

Fifty-seven patients, most with stage 3 acute kidney injury, were included. The 53% mortality rate among the 38 patients requiring CRRT was significantly higher than the 0% mortality rate among the 19 patients not requiring CRRT or intermittent hemodialysis. Increased duration of CRRT was not significantly associated with decreased survival. Fifteen CRRT patients required transition to intermittent hemodialysis. Of the CRRT patients who survived, 94% experienced renal recovery. Extracorporeal membrane oxygenation was instituted in 17 patients; 15 of these patients required CRRT.

CONCLUSIONS

Acute kidney injury is common in patients with severe ARDS caused by pH1N1 infection. CRRT is a significant risk factor for increased mortality, but most patients who survived experienced full renal recovery.

Standardized, Interdepartmental, Simulation-Based Central Line Insertion Course Closes an Educational Gap and Improves Intern Comfort with the Procedure

Central line placement is a common procedure, routinely performed by junior residents in medical and surgical departments. Before this project, no standardized instructional course on the insertion of central lines existed at our institution, and few interns had received formal ultrasound training. Interns from five departments participated in a simulation-based central line insertion course. Intern familiarity with the procedure and with ultrasound, as well as their prior experience with line placement and their level of comfort, was assessed. Of the 99 interns in participating departments, 45 per cent had been trained as ofOctober 2015. Forty-one per cent were female. The majority (59.5%) had no prior formal ultrasound training, and 46.0 per cent had never placed a line as primary operator. Scores increased significantly, from a precourse score mean of 13.7 to a postcourse score mean of 16.1, P < 0.001. All three of the self-reported measures of comfort with ultrasound also improved significantly. All interns reported the course was “very much” helpful, and 100 per cent reported they felt “somewhat” or “much” more comfortable with the procedure after attendance. To our knowledge, this is the first hospital-wide, standardized, simulation-based central line insertion course in the United States. Preliminary results indicate overwhelming satisfaction with the course, better ultrasound preparedness, and improved comfort with central line insertion.

Are Predictive Energy Expenditure Equations in Ventilated Surgery Patients Accurate?

BACKGROUND:

While indirect calorimetry (IC) is the gold standard used to calculate specific calorie needs in the critically ill, predictive equations are frequently utilized at many institutions for various reasons. Prior studies suggest these equations frequently misjudge actual resting energy expenditure (REE) in medical and mixed intensive care unit (ICU) patients; however, their utility for surgical ICU (SICU) patients has not been fully evaluated. Therefore, the objective of this study was to compare the REE measured by IC with REE calculated using specific calorie goals or predictive equations for nutritional support in ventilated adult SICU patients.

MATERIALS AND METHODS:

A retrospective review of prospectively collected data was performed on all adults (n = 419, 18-91 years) mechanically ventilated for >24 hours, with an Fio₂ ≤ 60%, who met IC screening criteria. Caloric needs were estimated using Harris-Benedict equations (HBEs), and 20, 25, and 30 kcal/kg/d with actual (ABW), adjusted (ADJ), and ideal body (IBW) weights. The REE was measured using IC.

RESULTS:

The estimated REE was considered accurate when within ±10% of the measured REE by IC. The HBE, 20, 25, and 30 kcal/kg/d estimates of REE were found to be inaccurate regardless of age, gender, or weight. The HBE and 20 kcal/kg/d underestimated REE, while 25 and 30 kcal/kg/d overestimated REE. Of the methods studied, those found to most often accurately estimate REE were the HBE using ABW, which was accurate 35% of the time, and 25 kcal/kg/d ADJ, which was accurate 34% of the time. This difference was not statistically significant.

CONCLUSION:

Using HBE, 20, 25, or 30 kcal/kg/d to estimate daily caloric requirements in critically ill surgical patients is inaccurate compared to REE measured by IC. In SICU patients with nutrition requirements essential to recovery, IC measurement should be performed to guide clinicians in determining goal caloric requirements.

House staff-led interdisciplinary morbidity and mortality conference promotes systematic improvement

BACKGROUND

Improvements in patient safety are critical to improving clinical outcomes. We present a resident-led interdisciplinary morbidity and mortality (M&M) conference utilizing postconference task forces to identify unique system issues, classify key contributors to interdisciplinary complications, and implement systems solutions. The conference also served to facilitate resident involvement in quality improvement projects.

MATERIALS AND METHODS

Members of the UNC Housestaff Council designed and implemented a hospital-wide M&M conference. Cases involving two or more service lines and resulting from systematic failures were selected for presentation by an interdisciplinary group of residents involved in the patient's care. Postconference task forces addressed problems and developed initiatives to improve care.

RESULTS

Of the 15 cases presented, 60% were attributable to an error in judgment, 26% to an error in diagnosis, and 13% to an error in technique. Communication (67%), coordination/care utilization (47%), poor process/workflow (40%), and inadequate training (33%) were the main associated contributing factors. Poor communication contributed to all complications resulting from an error in judgment. Inadequate training and poor workflow were the most common contributing factors with an error in technique. Poor utilization of care and inadequate processes were most common with an error in diagnosis. Postconference task forces identified system-based improvement projects in 73% (11 of 15) of cases with 82% (9 of 11) of projects successfully implemented or in process.

CONCLUSIONS

House staff-led interdisciplinary M&M conference utilizing postconference task forces is an ideal setting to identify unique system issues and implement system-based improvement strategies.

Abstract B71: Multiplexed kinase inhibitor beads identify multiple pathways of resistance to PI3K inhibition facilitating the rational selection of novel combination therapies in pancreatic cancer

KRAS mutational activation plays a critical role in tumorigenesis, but exactly which downstream KRAS effector pathway is critical for this role remains less clear. One of the most studied downstream pathways is the phosphatidylinositol-3-kinase (PI3K) pathway which mediates cellular metabolism, growth, and survival. We have previously shown using validated pancreatic ductal adenocarcinoma (PDAC) patient derived xenograft (PDX) mouse models that treatment with BKM120 (a pan-class 1 PI3K inhibitor, currently in Phase I/II clinical trials) resulted in tumor growth inhibition (p = 0.017) but not regression. In this study, we evaluated possible mechanisms of resistance to BKM120 therapy. We developed a novel multiplex inhibitor bead/mass spectrometry (MIB/MS) assay to measure the activation state of the kinome. We have recently shown that kinome response to kinase inhibitor therapy (i.e. kinome reprogramming) is a potential mechanism of resistance in triple negative breast cancer in response to MEK inhibition and in drug-resistant leukemia in response to imatinib. We hypothesized that kinome reprogramming may play a role in resistance to PI3K inhibition in PDAC and used MIB/MS to identify second targets that may be used in combination with PI3K inhibitors.

We found kinome reprogramming in response to PI3K inhibition through both previously known as well as less studied pathways. For instance, we found MEK1 and MEK2 activation in response to BKM120 treatment. MEK activation has previously been implicated in resistance to PI3K inhibition and combined MEK and PI3K inhibition has been shown to be synergistic in PDAC. However, our results suggest that resistance to PI3K may be mediated through many more pathways than MEK alone. We found ErbB1, ErbB2 and ErbB3 activation in response to BKM120 treatment in both cell lines and PDX tumors. ErbB2 and ErbB3 activation has previously been noted in response to PI3K inhibition in breast cancer. However, no studies have evaluated this combination in PDAC. Thus we evaluated the effect of combined PI3K and pan-ErbB inhibition in a panel of 10 PDAC cell lines using BKM120 and dacomitinib (a pan-ErbB inhibitor currently in Phase III clinical trials). Combined treatment with BKM120 and dacomitinib inhibited proliferation in 10 of 10 PDAC cell lines evaluated. This combination showed impressive synergy across all cell lines with a mean combination index of 0.24 (0.00245 – 0.49).

MIB/MS is a powerful unbiased approach to identify second targets for combination therapy. We identified both known and novel kinase pathways that may mediate resistance to PI3K inhibition in PDAC. Our results suggest that pan-ErbB inhibition may be a promising second target in combination with PI3K inhibition in PDAC. Combination studies in PDX models are ongoing. Pan-ErbB and PI3K inhibition in PDAC may be more effective than either single agent alone and should be considered in clinical trials.

Citation Format: Christopher J. Tignanelli, Jeran Stratford, Richard Moffitt, Rachel Reuther, Gary L. Johnson, Jen Jen Yeh. Multiplexed kinase inhibitor beads identify multiple pathways of resistance to PI3K inhibition facilitating the rational selection of novel combination therapies in pancreatic cancer. [abstract]. In: Proceedings of the AACR Special Conference on Pancreatic Cancer: Innovations in Research and Treatment; May 18-21, 2014; New Orleans, LA. Philadelphia (PA): AACR; Cancer Res 2015;75(13 Suppl):Abstract nr B71.

KRAS and PIK3CA Mutation Frequencies in Patient-derived Xenograft Models of Pancreatic and Colorectal Cancer Are Reflective of Patient Tumors and Stable Across Passages

One obstacle in the translation of advances in cancer research into the clinic is a deficiency of adequate preclinical models that recapitulate human disease. Patient-derived xenograft (PDX) models are established by engrafting patient tumor tissue into mice and are advantageous because they capture tumor heterogeneity. One concern with these models is that selective pressure could lead to mutational drift and thus be an inaccurate reflection of patient tumors. Therefore, we evaluated if mutational frequency in PDX models is reflective of patient populations and if crucial mutations are stable across passages. We examined KRAS and PIK3CA gene mutations from pancreatic ductal adenocarcinoma (PDAC) (n = 30) and colorectal cancer (CRC) (n = 37) PDXs for as many as eight passages. DNA was isolated from tumors and target sequences were amplified by polymerase chain reaction. KRAS codons 12/13 and PIK3CA codons 542/545/1047 were examined using pyrosequencing. Twenty-three of 30 (77%) PDAC PDXs had KRAS mutations and one of 30 (3%) had PIK3CA mutations. Fifteen of 37 (41%) CRC PDXs had KRAS mutations and three of 37 (8%) had PIK3CA mutations. Mutations were 100 per cent preserved across passages. We found that the frequency of KRAS (77%) and PIK3CA (3%) mutations in PDAC PDX was similar to frequencies in patient tumors (71 to 100% KRAS, 0 to 11% PIK3CA). Similarly, KRAS (41%) and PIK3CA (8%) mutations in CRC PDX closely paralleled patient tumors (35 to 51% KRAS, 12 to 21% PIK3CA). The accurate mirroring and stability of genetic changes in PDX models compared with patient tumors suggest that these models are good preclinical surrogates for patient tumors.

KRAS and PIK3CA mutation frequencies in patient-derived xenograft models of pancreatic and colorectal cancer are reflective of patient tumors and stable across passages

One obstacle in the translation of advances in cancer research into the clinic is a deficiency of adequate preclinical models that recapitulate human disease. Patient-derived xenograft (PDX) models are established by engrafting patient tumor tissue into mice and are advantageous because they capture tumor heterogeneity. One concern with these models is that selective pressure could lead to mutational drift and thus be an inaccurate reflection of patient tumors. Therefore, we evaluated if mutational frequency in PDX models is reflective of patient populations and if crucial mutations are stable across passages. We examined KRAS and PIK3CA gene mutations from pancreatic ductal adenocarcinoma (PDAC) (n = 30) and colorectal cancer (CRC) (n = 37) PDXs for as many as eight passages. DNA was isolated from tumors and target sequences were amplified by polymerase chain reaction. KRAS codons 12/13 and PIK3CA codons 542/545/1047 were examined using pyrosequencing. Twenty-three of 30 (77%) PDAC PDXs had KRAS mutations and one of 30 (3%) had PIK3CA mutations. Fifteen of 37 (41%) CRC PDXs had KRAS mutations and three of 37 (8%) had PIK3CA mutations. Mutations were 100 per cent preserved across passages. We found that the frequency of KRAS (77%) and PIK3CA (3%) mutations in PDAC PDX was similar to frequencies in patient tumors (71 to 100% KRAS, 0 to 11% PIK3CA). Similarly, KRAS (41%) and PIK3CA (8%) mutations in CRC PDX closely paralleled patient tumors (35 to 51% KRAS, 12 to 21% PIK3CA). The accurate mirroring and stability of genetic changes in PDX models compared with patient tumors suggest that these models are good preclinical surrogates for patient tumors.

Circulating tumor cells as a biomarker of response to treatment in patient-derived xenograft mouse models of pancreatic adenocarcinoma

Circulating tumor cells (CTCs) are cells shed from solid tumors into circulation and have been shown to be prognostic in the setting of metastatic disease. These cells are obtained through a routine blood draw and may serve as an easily accessible marker for monitoring treatment effectiveness. Because of the rapid progression of pancreatic ductal adenocarcinoma (PDAC), early insight into treatment effectiveness may allow for necessary and timely changes in treatment regimens. The objective of this study was to evaluate CTC burden as a biomarker of response to treatment with a oral phosphatidylinositol-3-kinase inhibitor, BKM120, in patient-derived xenograft (PDX) mouse models of PDAC. PDX mice were randomized to receive vehicle or BKM120 treatment for 28 days and CTCs were enumerated from whole blood before and after treatment using a microfluidic chip that selected for EpCAM (epithelial cell adhesion molecule) positive cells. This microfluidic device allowed for the release of captured CTCs and enumeration of these cells via their electrical impedance signatures. Median CTC counts significantly decreased in the BKM120 group from pre- to post-treatment (26.61 to 2.21 CTCs/250 µL, p = 0.0207) while no significant change was observed in the vehicle group (23.26 to 11.89 CTCs/250 µL, p = 0.8081). This reduction in CTC burden in the treatment group correlated with tumor growth inhibition indicating CTC burden is a promising biomarker of response to treatment in preclinical models. Mutant enriched sequencing of isolated CTCs confirmed that they harbored KRAS G12V mutations, identical to the matched tumors. In the long-term, PDX mice are a useful preclinical model for furthering our understanding of CTCs. Clinically, mutational analysis of CTCs and serial monitoring of CTC burden may be used as a minimally invasive approach to predict and monitor treatment response to guide therapeutic regimens.

UV activation of polymeric high aspect ratio microstructures: ramifications in antibody surface loading for circulating tumor cell selection

The need to activate thermoplastic surfaces using robust and efficient methods has been driven by the fact that replication techniques can be used to produce microfluidic devices in a high production mode and at low cost, making polymer microfluidics invaluable for in vitro diagnostics, such as circulating tumor cell (CTC) analysis, where device disposability is critical to mitigate artifacts associated with sample carryover. Modifying the surface chemistry of thermoplastic devices through activation techniques can be used to increase the wettability of the surface or to produce functional scaffolds to allow for the covalent attachment of biologics, such as antibodies for CTC recognition. Extensive surface characterization tools were used to investigate UV activation of various surfaces to produce uniform and high surface coverage of functional groups, such as carboxylic acids in microchannels of different aspect ratios. We found that the efficiency of the UV activation process is highly dependent on the microchannel aspect ratio and the identity of the thermoplastic substrate. Colorimetric assays and fluorescence imaging of UV-activated microchannels following EDC/NHS coupling of Cy3-labeled oligonucleotides indicated that UV-activation of a PMMA microchannel with an aspect ratio of ~3 was significantly less efficient toward the bottom of the channel compared to the upper sections. This effect was a consequence of the bulk polymer's damping of the modifying UV radiation due to absorption artifacts. In contrast, this effect was less pronounced for COC. Moreover, we observed that after thermal fusion bonding of the device's cover plate to the substrate, many of the generated functional groups buried into the bulk rendering them inaccessible. The propensity of this surface reorganization was found to be higher for PMMA compared to COC. As an example of the effects of material and microchannel aspect ratios on device functionality, thermoplastic devices for the selection of CTCs from whole blood were evaluated, which required the immobilization of monoclonal antibodies to channel walls. From our results, we concluded the CTC yield and purity of isolated CTCs were dependent on the substrate material with COC producing the highest clinical yields for CTCs as well as better purities compared to PMMA.

The effect of residual on the stochastic gating of -regulated channel models

Single-channel models of intracellular Ca(2+) channels such as the inositol 1,4,5-trisphosphate receptor and ryanodine receptor often assume that Ca(2+)-dependent transitions are mediated by a constant background [Ca(2+)] as opposed to a dynamic [Ca(2+)] representing the formation and collapse of a localized Ca(2+) domain. This assumption neglects the fact that Ca(2+) released by open intracellular Ca(2+) channels may influence subsequent gating through the processes of Ca(2+)-activation or -inactivation. We study the effect of such "residual Ca(2+)" from previous channel opening on the stochastic gating of minimal and realistic single-channel models coupled to a restricted cytoplasmic compartment. Using Monte Carlo simulation as well as analytical and numerical solution of a system of advection-reaction equations for the probability density of the domain [Ca(2+)] conditioned on the state of the channel, we determine how the steady-state open probability (p(open)) of single-channel models of Ca(2+)-regulated Ca(2+) channels depends on the time constant for Ca(2+) domain formation and collapse. As expected, p(open) for a minimal model including Ca(2+) activation increases as the domain time constant becomes large compared to the open and closed dwell times of the channel, that is, on average the channel is activated by residual Ca(2+) from previous openings. Interestingly, p(open) for a channel model that is inactivated by Ca(2+) also increases as a function of the domain time constant when the maximum domain [Ca(2+)] is fixed, because slow formation of the Ca(2+) domain attenuates Ca(2+)-mediated inactivation. Conversely, when the source amplitude of the channel is fixed, increasing the domain time constant leads to elevated domain [Ca(2+)] and decreased open probability. Consistent with these observations, a realistic De Young-Keizer-like IP(3)R model responds to residual Ca(2+) with a steady-state open probability that is a monotonic function of the domain time constant, though minimal models that include both Ca(2+)-activation and -inactivation show more complex behavior. We show how the probability density approach described here can be generalized for arbitrarily complex channel models and for any value of the domain time constant. In addition, we present a comparatively simple numerical procedure for estimating p(open) for models of Ca(2+)-regulated Ca(2+) channels in the limit of a very fast or very slow Ca(2+) domain. When the ordinary differential equation for the [Ca(2+)] in a restricted cytoplasmic compartment is replaced by a partial differential equation for the buffered diffusion of intracellular Ca(2+) in a homogeneous isotropic cytosol, we find the dependence of p(open) on the buffer time constant is qualitatively similar to the above-mentioned results.