Risk of postpartum readmission after hypertensive disorder of pregnancy and variation by discharge antihypertensive medication prescription

BACKGROUND

Patients with hypertensive disorders of pregnancy have a high rate of postpartum readmission.

OBJECTIVE

This study aimed to evaluate whether the type of antihypertensive medication prescribed at discharge was associated with postpartum readmission after a hypertensive disorder of pregnancy.

STUDY DESIGN

This was a retrospective cohort study of 57,254 pregnancies complicated by hypertensive disorders of pregnancy between 2012 and 2018 in the electronic obstetrical database of Kaiser Permanente Northern California. Postpartum readmissions occurred within 6 weeks after discharge from delivery hospitalization. Cox regression models were used to evaluate the association between the type of antihypertensive medication prescription at discharge (none, labetalol only, nifedipine only, or 2 or more antihypertensive medications) and postpartum readmission, adjusted for type of hypertensive disorder of pregnancy, final inpatient systolic and diastolic blood pressures, age, body mass index, mode of delivery, insurance status, race and ethnicity, delivery facility, comorbidity score, smoking, preterm delivery, parity, and Neighborhood Deprivation Index.

RESULTS

Among eligible patients with a hypertensive disorder of pregnancy, 1696 (3.0%) were readmitted within 6 weeks. Approximately 86% of patients were discharged without a prescription for antihypertensive medication; among those discharged with a prescription for antihypertensive medication, most were prescribed either labetalol only (54%) or nifedipine only (30%). The unadjusted readmission risk was the highest for patients discharged with a prescription for labetalol only (7.6%), lower for those discharged with a prescription for nifedipine only (3.6%) or 2 or more antihypertensive medications (3.2%), and the lowest for those discharged without a prescription for antihypertensive medication (2.5%). In the adjusted models, compared with discharge without a prescription for antihypertensive medication, discharge with a prescription for labetalol only was associated with a 63% (hazard ratio, 1.63; 95% confidence interval, 1.41-1.88) greater incidence of postpartum readmission, and discharge with a prescription for nifedipine only and discharge with a prescription for 2 or more antihypertensive medications were associated with 26% (hazard ratio, 0.74; 95% confidence interval, 0.59-0.93) and 47% (hazard ratio, 0.53; 95% confidence interval, 0.38-0.74) lower incidence of postpartum readmission, respectively. There was no strong evidence to suggest that the effect of the type of antihypertensive medication at discharge on the incidence of readmission varied by race and ethnicity (interaction P=.88). The results indicating an elevated risk associated with labetalol use were consistent in models that excluded patients with prepregnancy hypertension.

CONCLUSION

Discharge with a prescription for nifedipine alone or multiple antihypertensive medications (vs no medication) was associated with a lower incidence of readmission, whereas discharge with a prescription for labetalol alone was associated with an elevated readmission incidence. A large-scale, prospective research to compare the effectiveness of commonly prescribed hypertension medications at discharge is warranted.

The Gut Microbiome Modulates Body Temperature Both in Sepsis and Health

Rationale: Among patients with sepsis, variation in temperature trajectories predicts clinical outcomes. In healthy individuals, normal body temperature is variable and has decreased consistently since the 1860s. The biologic underpinnings of this temperature variation in disease and health are unknown. Objectives: To establish and interrogate the role of the gut microbiome in calibrating body temperature. Methods: We performed a series of translational analyses and experiments to determine whether and how variation in gut microbiota explains variation in body temperature in sepsis and in health. We studied patient temperature trajectories using electronic medical record data. We characterized gut microbiota in hospitalized patients using 16S ribosomal RNA gene sequencing. We modeled sepsis using intraperitoneal LPS in mice and modulated the microbiome using antibiotics, germ-free, and gnotobiotic animals. Measurements and Main Results: Consistent with prior work, we identified four temperature trajectories in patients hospitalized with sepsis that predicted clinical outcomes. In a separate cohort of 116 hospitalized patients, we found that the composition of patients' gut microbiota at admission predicted their temperature trajectories. Compared with conventional mice, germ-free mice had reduced temperature loss during experimental sepsis. Among conventional mice, heterogeneity of temperature response in sepsis was strongly explained by variation in gut microbiota. Healthy germ-free and antibiotic-treated mice both had lower basal body temperatures compared with control animals. The Lachnospiraceae family was consistently associated with temperature trajectories in hospitalized patients, experimental sepsis, and antibiotic-treated mice. Conclusions: The gut microbiome is a key modulator of body temperature variation in both health and critical illness and is thus a major, understudied target for modulating physiologic heterogeneity in sepsis.

Endovascular experience at an academic office-based procedure center

OBJECTIVE

The number of office-based procedure centers with the capability of performing a wide range of endovascular procedures has substantially increased over the past decade. This shift in practice settings has occurred faster in the private sector as compared to the academic environment. The purpose of our study was to evaluate the clinical outcomes of endovascular procedures performed at a dedicated academic outpatient procedural center.

METHODS

We reviewed the clinical data of 400 patients who underwent 499 endovascular procedures in a university-based, academic outpatient procedure center between November 2013 and December 2016. Outcomes analyzed included procedure-related complications, limb loss, mortality, and emergency department visits or hospital admissions that occurred within 30 days following the procedure.

RESULTS

The 400 patients had a mean age of 65 ± 13 years with slightly more females (51%; n = 203) as compared to males (49%; n = 197). Most patients (71%; 284) were Caucasian while 80 (20%) were African-Americans. Associated comorbidities included hypertension (86%), diabetes mellitus (51%), chronic kidney disease (42%), and obesity (mean body mass index of 29 ± 6). Based on anesthetic risk, most were ASA class 3 (81%), while ASA 1 and 2 comprised 17% and ASA 4 only 2%. Medicare beneficiaries accounted for 254 (64%) of our patients. Pre-operative studies included mainly duplex ultrasound (62%) and other noninvasive arterial studies (57%).The mean procedural time was 58 min (range, 7 to 200) with an overall technical success rate of 97%. There were no deaths. Complications developed in 10 patients following the 483 procedures (2.1%) being hospitalized with four of them transferred directly to the emergency room. The reasons for these hospitalizations included acute limb ischemia, arterial pseudoaneurysm, deep vein thrombosis, congestive heart failure, myocardial infarction, and lower extremity pain not vascular in origin. Financial reimbursement at the office-based center was higher than that seen with hospital-based procedures.

CONCLUSIONS

Endovascular procedures performed in an academic office-based procedure center are safe and associated with good clinical outcomes. A small minority of patients have subsequent ER visits or hospital admissions. Academic institutions should consider adding an office-based procedure center based on today's competitive healthcare market.

In critically ill patients, anti-anaerobic antibiotics increase risk of adverse clinical outcomes

BACKGROUND

Critically ill patients routinely receive antibiotics with activity against anaerobic gut bacteria. However, in other disease states and animal models, gut anaerobes are protective against pneumonia, organ failure and mortality. We therefore designed a translational series of analyses and experiments to determine the effects of anti-anaerobic antibiotics on the risk of adverse clinical outcomes among critically ill patients.

METHODS

We conducted a retrospective single-centre cohort study of 3032 critically ill patients, comparing patients who did and did not receive early anti-anaerobic antibiotics. We compared intensive care unit outcomes (ventilator-associated pneumonia (VAP)-free survival, infection-free survival and overall survival) in all patients and changes in gut microbiota in a subcohort of 116 patients. In murine models, we studied the effects of anaerobe depletion in infectious (Klebsiella pneumoniae and Staphylococcus aureus pneumonia) and noninfectious (hyperoxia) injury models.

RESULTS

Early administration of anti-anaerobic antibiotics was associated with decreased VAP-free survival (hazard ratio (HR) 1.24, 95% CI 1.06-1.45), infection-free survival (HR 1.22, 95% CI 1.09-1.38) and overall survival (HR 1.14, 95% CI 1.02-1.28). Patients who received anti-anaerobic antibiotics had decreased initial gut bacterial density (p=0.00038), increased microbiome expansion during hospitalisation (p=0.011) and domination by Enterobacteriaceae spp. (p=0.045). Enterobacteriaceae were also enriched among respiratory pathogens in anti-anaerobic-treated patients (p<2.2×10^-16). In murine models, treatment with anti-anaerobic antibiotics increased susceptibility to Enterobacteriaceae pneumonia (p<0.05) and increased the lethality of hyperoxia (p=0.0002).

CONCLUSIONS

In critically ill patients, early treatment with anti-anaerobic antibiotics is associated with increased mortality. Mechanisms may include enrichment of the gut with respiratory pathogens, but increased mortality is incompletely explained by infections alone. Given consistent clinical and experimental evidence of harm, the widespread use of anti-anaerobic antibiotics should be reconsidered.

Predicting the long-term impact of rotavirus vaccination in 112 countries from 2006 to 2034: A transmission modeling analysis

Rotavirus vaccination has been shown to reduce rotavirus burden in many countries, but the long-term magnitude of vaccine impacts is unclear, particularly in low-income countries. We use a transmission model to estimate the long-term impact of rotavirus vaccination on deaths and disability adjusted life years (DALYs) from 2006 to 2034 for 112 low- and middle-income countries. We also explore the predicted effectiveness of a one- vs two- dose series and the relative contribution of direct vs indirect effects to overall impacts. To validate the model, we compare predicted percent reductions in severe rotavirus cases with the percent reduction in rotavirus positivity among gastroenteritis hospital admissions for 10 countries with pre- and post-vaccine introduction data. We estimate that vaccination would reduce deaths from rotavirus by 49.1 % (95 % UI: 46.6-54.3 %) by 2034 under realistic coverage scenarios, compared to a scenario without vaccination. Most of this benefit is due to direct benefit to vaccinated individuals (explaining 69-97 % of the overall impact), but indirect protection also appears to enhance impacts. We find that a one-dose schedule would only be about 57 % as effective as a two-dose schedule 12 years after vaccine introduction. Our model closely reproduced observed reductions in rotavirus positivity in the first few years after vaccine introduction in select countries. Rotavirus vaccination is likely to have a substantial impact on rotavirus gastroenteritis and its mortality burden. To sustain this benefit, the complete series of doses is needed.

The role of booster vaccination and ongoing viral evolution in seasonal circulation of SARS-CoV-2

Periodic resurgences of COVID-19 in the coming years can be expected, while public health interventions may be able to reduce their intensity. We used a transmission model to assess how the use of booster doses and non-pharmaceutical interventions (NPIs) amid ongoing pathogen evolution might influence future transmission waves. We find that incidence is likely to increase as NPIs relax, with a second seasonally driven surge expected in autumn 2022. However, booster doses can greatly reduce the intensity of both waves and reduce cumulative deaths by 20% between 7 January 2022 and 7 January 2023. Reintroducing NPIs during the autumn as incidence begins to increase again could also be impactful. Combining boosters and NPIs results in a 30% decrease in cumulative deaths, with potential for greater impacts if variant-adapted boosters are used. Reintroducing these NPIs in autumn 2022 as transmission rates increase provides similar benefits to sustaining NPIs indefinitely (307 000 deaths with indefinite NPIs and boosters compared with 304 000 deaths with transient NPIs and boosters). If novel variants with increased transmissibility or immune escape emerge, deaths will be higher, but vaccination and NPIs are expected to remain effective tools to decrease both cumulative and peak health system burden, providing proportionally similar relative impacts.

Antibiotics cause metabolic changes in mice primarily through microbiome modulation rather than behavioral changes

Background

The microbiome is an important and increasingly-studied mediator of organismal metabolism, although how the microbiome affects metabolism remains incompletely understood. Many investigators use antibiotics to experimentally perturb the microbiome. However, antibiotics have poorly understood yet profound off-target effects on behavior and diet, including food and water aversion, that can confound experiments and limit their applicability. We thus sought to determine the relative influence of microbiome modulation and off-target antibiotic effects on the behavior and metabolic activity of mice.

Results

Mice treated with oral antibiotics via drinking water exhibited significant weight loss in fat, liver, and muscle tissue. These mice also exhibited a reduction in water and food consumption, with marked variability across antibiotic regimens. While administration of bitter-tasting but antimicrobially-inert compounds caused a similar reduction in water consumption, this did not cause tissue weight loss or reduced food consumption. Mice administered intraperitoneal antibiotics (bypassing the gastrointestinal tract) exhibited reduced tissue weights and oral intake, comparable to the effects of oral antibiotics. Antibiotic-treated germ-free mice did not have reduced tissue weights, providing further evidence that direct microbiome modulation (rather than behavioral effects) mediates these metabolic changes.

Conclusions

While oral antibiotics cause profound effects on food and water consumption, antibiotic effects on organismal metabolism are primarily mediated by microbiome modulation. We demonstrate that tissue-specific weight loss following antibiotic administration is due primarily to microbiome effects rather than food and water aversion, and identify antibiotic regimens that effectively modulate gut microbiota while minimizing off-target behavioral effects.

Cerebral Hyperperfusion Syndrome Presenting As Status Epilepticus Following Carotid Endarterectomy

Cerebral Hyperperfusion Syndrome (CHS) is a rare syndrome, commonly described as a prodrome of symptoms including a severe ipsilateral headache, focal neurological deficits, intracerebral hemorrhage, and occasionally includes seizures or encephalopathy. Our case involves a 76-year-old man who underwent a left carotid endarterectomy (CEA) for symptomatic high-grade stenosis of his left carotid artery. Post-operative day one, the patient was seen and examined in the early morning and found to be doing well, with blood pressures well-controlled and at his neurologic baseline. Three hours later, he was reported to have a sudden spike in his blood pressure and was experiencing focal motor seizures involving the right arm and face, both of which were unrelieved by anti-hypertensives and anti-seizure medications. The patient subsequently developed worsening respiratory function requiring intubation for status epilepticus. Repeat head and neck imaging with CT, CT angiography, and MRI demonstrated the known previous subacute infarct with new cerebral edema, patent carotid arteries bilaterally, and no acute infarct or intracerebral hemorrhage.

While CHS is a rare syndrome with well-documented symptomatology, we present a unique case in which focal motor status epilepticus was the only presenting symptom in a patient who otherwise meets the criteria of CHS based on radiographic evidence of cerebral edema following an elective CEA.

Whole lung tissue is the preferred sampling method for amplicon-based characterization of murine lung microbiota

BACKGROUND

Low-biomass microbiome studies (such as those of the lungs, placenta, and skin) are vulnerable to contamination and sequencing stochasticity, which obscure legitimate microbial signal. While human lung microbiome studies have rigorously identified sampling strategies that reliably capture microbial signal from these low-biomass microbial communities, the optimal sampling strategy for characterizing murine lung microbiota has not been empirically determined. Performing accurate, reliable characterization of murine lung microbiota and distinguishing true microbial signal from noise in these samples will be critical for further mechanistic microbiome studies in mice.

RESULTS

Using an analytic approach grounded in microbial ecology, we compared bacterial DNA from the lungs of healthy adult mice collected via two common sampling approaches: homogenized whole lung tissue and bronchoalveolar lavage (BAL) fluid. We quantified bacterial DNA using droplet digital PCR, characterized bacterial communities using 16S rRNA gene sequencing, and systematically assessed the quantity and identity of bacterial DNA in both specimen types. We compared bacteria detected in lung specimens to each other and to potential source communities: negative (background) control specimens and paired oral samples. By all measures, whole lung tissue in mice contained greater bacterial signal and less evidence of contamination than did BAL fluid. Relative to BAL fluid, whole lung tissue exhibited a greater quantity of bacterial DNA, distinct community composition, decreased sample-to-sample variation, and greater biological plausibility when compared to potential source communities. In contrast, bacteria detected in BAL fluid were minimally different from those of procedural, reagent, and sequencing controls.

CONCLUSIONS

An ecology-based analytical approach discriminates signal from noise in this low-biomass microbiome study and identifies whole lung tissue as the preferred specimen type for murine lung microbiome studies. Sequencing, analysis, and reporting of potential source communities, including negative control specimens and contiguous biological sites, are crucial for biological interpretation of low-biomass microbiome studies, independent of specimen type. Video abstract.

Lung and gut microbiota are altered by hyperoxia and contribute to oxygen-induced lung injury in mice

Inhaled oxygen, although commonly administered to patients with respiratory disease, causes severe lung injury in animals and is associated with poor clinical outcomes in humans. The relationship between hyperoxia, lung and gut microbiota, and lung injury is unknown. Here, we show that hyperoxia conferred a selective relative growth advantage on oxygen-tolerant respiratory microbial species (e.g., Staphylococcus aureus) as demonstrated by an observational study of critically ill patients receiving mechanical ventilation and experiments using neonatal and adult mouse models. During exposure of mice to hyperoxia, both lung and gut bacterial communities were altered, and these communities contributed to oxygen-induced lung injury. Disruption of lung and gut microbiota preceded lung injury, and variation in microbial communities correlated with variation in lung inflammation. Germ-free mice were protected from oxygen-induced lung injury, and systemic antibiotic treatment selectively modulated the severity of oxygen-induced lung injury in conventionally housed animals. These results suggest that inhaled oxygen may alter lung and gut microbial communities and that these communities could contribute to lung injury.

Substantial and sustained reduction in under-5 mortality, diarrhea, and pneumonia in Oshikhandass, Pakistan: evidence from two longitudinal cohort studies 15 years apart

BACKGROUND

Oshikhandass is a rural village in northern Pakistan where a 1989-1991 verbal autopsy study showed that diarrhea and pneumonia were the top causes of under-5 mortality. Intensive surveillance, active community health education and child health interventions were delivered in 1989-1996; here we assess improvements in under-5 mortality, diarrhea, and pneumonia over this period and 15 years later.

METHODS

Two prospective open-cohort studies in Oshikhandass from 1989 to 1996 (Study 1) and 2011-2014 (Study 2) enrolled all children under age 60 months. Study staff trained using WHO guidelines, conducted weekly household surveillance and promoted knowledge on causes and management of diarrhea and pneumonia. Information about household characteristics and socioeconomic status was collected. Hurdle models were constructed to examine putative risk factors for diarrhea and pneumonia.

RESULTS

Against a backdrop of considerable change in the socioeconomic status of the community, under-5 mortality, which declined over the course of Study 1 (from 114.3 to 79.5 deaths/1000 live births (LB) between 1989 and 1996), exceeded Sustainable Development Goal 3 by Study 2 (19.8 deaths/ 1000 LB). Reductions in diarrhea prevalence (20.3 to 2.2 days/ Child Year [CY]), incidence (2.1 to 0.5 episodes/ CY), and number of bloody diarrhea episodes (18.6 to 5.2%) seen during Study 1, were sustained in Study 2. Pneumonia incidence was 0.5 episodes /CY in Study 1 and 0.2/CY in Study 2; only 5% of episodes were categorized as severe or very severe in both studies. While no individual factors predicted a statistically significant difference in diarrhea or pneumonia episodes, the combined effect of water, toilet and housing materials was associated with a significant decrease in diarrhea; higher household income was the most protective factor for pneumonia in Study 1.

CONCLUSIONS

We report a 4-fold decrease in overall childhood mortality, and a 2-fold decrease in childhood morbidity from diarrhea and pneumonia in a remote rural village in Pakistan between 1989 and 2014. We conclude that significant, sustainable improvements in child health may be achieved through improved socioeconomic status and promoting interactions between locally engaged health workers and the community, but that continued efforts are needed to improve health worker training, supervision, and the rational use of medications.

TRIAL REGISTRATION

Not Applicable.

Analysis of the Complete Genome of the Alkaliphilic and Phototrophic Firmicute Heliorestis convoluta Strain HHT

Despite significant interest and past work to elucidate the phylogeny and photochemistry of species of the Heliobacteriaceae, genomic analyses of heliobacteria to date have been limited to just one published genome, that of the thermophilic species Heliobacterium (Hbt.) modesticaldum str. Ice1^T. Here we present an analysis of the complete genome of a second heliobacterium, Heliorestis (Hrs.) convoluta str. HH^T, an alkaliphilic, mesophilic, and morphologically distinct heliobacterium isolated from an Egyptian soda lake. The genome of Hrs. convoluta is a single circular chromosome of 3.22 Mb with a GC content of 43.1% and 3263 protein-encoding genes. In addition to culture-based observations and insights gleaned from the Hbt. modesticaldum genome, an analysis of enzyme-encoding genes from key metabolic pathways supports an obligately photoheterotrophic lifestyle for Hrs. convoluta. A complete set of genes encoding enzymes for propionate and butyrate catabolism and the absence of a gene encoding lactate dehydrogenase distinguishes the carbon metabolism of Hrs. convoluta from its close relatives. Comparative analyses of key proteins in Hrs. convoluta, including cytochrome c₅₅₃ and the F_o alpha subunit of ATP synthase, with those of related species reveal variations in specific amino acid residues that likely contribute to the success of Hrs. convoluta in its highly alkaline environment.

Association Between Peripheral Blood Oxygen Saturation (SpO2)/Fraction of Inspired Oxygen (FiO2) Ratio Time at Risk and Hospital Mortality in Mechanically Ventilated Patients

INTRODUCTION

Acute respiratory failure requiring mechanical ventilation is a leading cause of mortality in the intensive care unit. Although single peripheral blood oxygen saturation/fraction of inspired oxygen (SpO2/FiO2) ratios of hypoxemia have been evaluated to risk-stratify patients with acute respiratory distress syndrome, the utility of longitudinal SpO2/FiO2 ratios is unknown.

OBJECTIVE

To assess time-based SpO2/FiO2 ratios ≤ 150-SpO2/FiO2 time at risk (SF-TAR)-for predicting mortality in mechanically ventilated patients.

METHODS

Retrospective, observational cohort study of mechanically ventilated patients at 21 community and 2 academic hospitals. Association between the SF-TAR in the first 24 hours of ventilation and mortality was examined using multivariable logistic regression and compared with the worst recorded isolated partial pressure of arterial oxygen/fraction of inspired oxygen (P/F) ratio.

RESULTS

In 28,758 derivation cohort admissions, every 10% increase in SF-TAR was associated with a 24% increase in adjusted odds of hospital mortality (adjusted odds ratio = 1.24; 95% confidence interval [CI] = 1.23-1.26); a similar association was observed in validation cohorts. Discrimination for mortality modestly improved with SF-TAR (area under the receiver operating characteristic curve [AUROC] = 0.81; 95% CI = 0.81-0.82) vs the worst P/F ratio (AUROC = 0.78; 95% CI = 0.78-0.79) and worst SpO2/FiO2 ratio (AUROC = 0.79; 95% CI = 0.79-0.80). The SF-TAR in the first 6 hours offered comparable discrimination for hospital mortality (AUROC = 0.80; 95% CI = 0.79-0.80) to the 24-hour SF-TAR.

CONCLUSION

The SF-TAR can identify ventilated patients at increased risk of death, offering modest improvements compared with single SpO2/FiO2 and P/F ratios. This longitudinal, noninvasive, and broadly generalizable tool may have particular utility for early phenotyping and risk stratification using electronic health record data in ventilated patients.

Functional neuroanatomy of interoceptive processing in children and adolescents: a pilot study

In adults, interoception – the sense of the physiological condition of the body - appears to influence emotion processing, cognition, behavior and various somatic and mental health disorders. Adults demonstrate frontal-insula-parietal-anterior cingulate cortex activation during the heartbeat detection task, a common interoceptive measure. Little, however, is known about the functional neuroanatomy underlying interoception in children. The current pilot study examined interoceptive processing in children and adolescents with fMRI while using the heartbeat detection task. Our main findings demonstrate that children as young as the age of six activate the left insula, cuneus, inferior parietal lobule and prefrontal regions. These findings are similar to those in adults when comparing heartbeat and tone detection conditions. Age was associated with increased activation within the dACC, orbital frontal cortex and the mid-inferior frontal gyri. Thus, our pilot study may provide important information about the neurodevelopment of interoceptive processing abilities in children and a task for future interoception neuroimaging studies in children.

Chemoorganotrophic Bacteria From Lake Fryxell, Antarctica, Including Pseudomonas Strain LFY10, a Cold-Adapted, Halotolerant Bacterium Useful in Teaching Labs

Lake Fryxell, situated in the McMurdo Dry Valleys of Antarctica, is an intriguing aquatic ecosystem because of its perennial ice cover, highly stratified water column, and extreme physicochemical conditions, which collectively restrict lake biodiversity to solely microbial forms. To expand our current understanding of the cultivable biodiversity of Lake Fryxell, water samples were collected from depths of 10 and 17 m, and pure cultures of eight diverse strains of aerobic, chemoorganotrophic bacteria were obtained. Despite having high 16S rRNA gene sequence similarity to mesophilic bacteria inhabiting various temperate environments, all Lake Fryxell isolates were psychrotolerant, with growth occurring at 0°C and optimal growth from 18–24°C for all isolates. Phylogenetic analyses showed the isolates to be members of six taxonomic groups, including the genera Brevundimonas, Arthrobacter, Sphingobium, Leifsonia, and Pseudomonas, as well as the family Microbacteriaceae (one strain could not reliably be assigned to a specific genus based on our analysis). Pseudomonas strain LFY10 stood out as a useful tool for teaching laboratory activities because of its substantial cold adaptation (visible growth is evident in 1–2 days at 4°C), beta-hemolytic activity, and halotolerance to 8.5% (w/v) NaCl. These cold-adapted bacteria likely play a role in carbon mineralization and other nutrient cycling in Lake Fryxell, and their characterization broadens our understanding of microbial biodiversity in aquatic polar ecosystems.

Advancing the Sustainability of US Agriculture through Long-Term Research

Agriculture in the United States must respond to escalating demands for productivity and efficiency, as well as pressures to improve its stewardship of natural resources. Growing global population and changing diets, combined with a greater societal awareness of agriculture's role in delivering ecosystem services beyond food, feed, fiber, and energy production, require a comprehensive perspective on where and how US agriculture can be sustainably intensified, that is, made more productive without exacerbating local and off-site environmental concerns. The USDA's Long-Term Agroecosystem Research (LTAR) network is composed of 18 locations distributed across the contiguous United States working together to integrate national and local agricultural priorities and advance the sustainable intensification of US agriculture. We explore here the concept of sustainable intensification as a framework for defining strategies to enhance production, environmental, and rural prosperity outcomes from agricultural systems. We also elucidate the diversity of factors that have shaped the past and present conditions of cropland, rangeland, and pastureland agroecosystems represented by the LTAR network and identify priorities for research in the areas of production, resource conservation and environmental quality, and rural prosperity. Ultimately, integrated long-term research on sustainable intensification at the national scale is critical to developing practices and programs that can anticipate and address challenges before they become crises.

Comparing Hospital Processes and Outcomes in California Medicare Beneficiaries: Simulation Prompts Reconsideration

INTRODUCTION

This article is not a traditional research report. It describes how conducting a specific set of benchmarking analyses led us to broader reflections on hospital benchmarking. We reexamined an issue that has received far less attention from researchers than in the past: How variations in the hospital admission threshold might affect hospital rankings. Considering this threshold made us reconsider what benchmarking is and what future benchmarking studies might be like. Although we recognize that some of our assertions are speculative, they are based on our reading of the literature and previous and ongoing data analyses being conducted in our research unit. We describe the benchmarking analyses that led to these reflections.

OBJECTIVES

The Centers for Medicare and Medicaid Services' Hospital Compare Web site includes data on fee-for-service Medicare beneficiaries but does not control for severity of illness, which requires physiologic data now available in most electronic medical records.To address this limitation, we compared hospital processes and outcomes among Kaiser Permanente Northern California's (KPNC) Medicare Advantage beneficiaries and non-KPNC California Medicare beneficiaries between 2009 and 2010.

METHODS

We assigned a simulated severity of illness measure to each record and explored the effect of having the additional information on outcomes.

RESULTS

We found that if the admission severity of illness in non-KPNC hospitals increased, KPNC hospitals' mortality performance would appear worse; conversely, if admission severity at non-KPNC hospitals' decreased, KPNC hospitals' performance would appear better.

CONCLUSION

Future hospital benchmarking should consider the impact of variation in admission thresholds.

A systematic review of care management interventions targeting multimorbidity and high care utilization

Background

Evidence supporting the effectiveness of care management programs for complex patients has been inconclusive. However, past reviews have not focused on complexity primarily defined by multimorbidity and healthcare utilization. We conducted a systematic review of care management interventions targeting the following three patient groups: adults with two or more chronic medical conditions, adults with at least one chronic medical condition and concurrent depression, and adults identified based solely on high past or predicted healthcare utilization.

Methods

Eligible studies were identified from PubMed, published between 06/01/2005 and 05/31/2015, and reported findings from a randomized intervention that tested a comprehensive, care management intervention. Identified interventions were grouped based on the three “complex” categories of interest (described above). Two investigators extracted data using a structured abstraction form and assessed RCT quality.

Results

We screened 989 article titles for eligibility from which 847 were excluded. After reviewing the remaining 142 abstracts, 83 articles were excluded. We reviewed the full-text of 59 full-text articles and identified 15 unique RCTs for the final analysis. Of these 15 studies, two focused on patients with two or more chronic medical conditions, seven on patients with at least one chronic medical condition and depression, and six on patients with high past or predicted healthcare utilization. Measured outcomes included utilization, chronic disease measures, and patient-reported outcomes. The seven studies targeting patients with at least one chronic medical condition and depression demonstrated significant improvement in depression symptoms (ranging from 9.2 to 48.7% improvement). Of the six studies that focused on high utilizers, two showed small reductions in utilization. The quality of the research methodology in most of the studies (12/15) was rated fair or poor.

Conclusions

Interventions were more likely to be successful when patients were selected based on having at least one chronic medical condition and concurrent depression, and when patient-reported outcomes were assessed. Future research should focus on the role of mental health in complex care management, finding better methods for identifying patients who would benefit most from care management, and determining which intervention components are needed for which patients.

Electronic supplementary material

The online version of this article (10.1186/s12913-018-2881-8) contains supplementary material, which is available to authorized users.

The Timing of Early Antibiotics and Hospital Mortality in Sepsis

RATIONALE

Prior sepsis studies evaluating antibiotic timing have shown mixed results.

OBJECTIVES

To evaluate the association between antibiotic timing and mortality among patients with sepsis receiving antibiotics within 6 hours of emergency department registration.

METHODS

Retrospective study of 35,000 randomly selected inpatients with sepsis treated at 21 emergency departments between 2010 and 2013 in Northern California. The primary exposure was antibiotics given within 6 hours of emergency department registration. The primary outcome was adjusted in-hospital mortality. We used detailed physiologic data to quantify severity of illness within 1 hour of registration and logistic regression to estimate the odds of hospital mortality based on antibiotic timing and patient factors.

MEASUREMENTS AND MAIN RESULTS

The median time to antibiotic administration was 2.1 hours (interquartile range, 1.4-3.1 h). The adjusted odds ratio for hospital mortality based on each hour of delay in antibiotics after registration was 1.09 (95% confidence interval [CI], 1.05-1.13) for each elapsed hour between registration and antibiotic administration. The increase in absolute mortality associated with an hour's delay in antibiotic administration was 0.3% (95% CI, 0.01-0.6%; P = 0.04) for sepsis, 0.4% (95% CI, 0.1-0.8%; P = 0.02) for severe sepsis, and 1.8% (95% CI, 0.8-3.0%; P = 0.001) for shock.

CONCLUSIONS

In a large, contemporary, and multicenter sample of patients with sepsis in the emergency department, hourly delays in antibiotic administration were associated with increased odds of hospital mortality even among patients who received antibiotics within 6 hours. The odds increased within each sepsis severity strata, and the increased odds of mortality were greatest in septic shock.

Slow and steady wins the race: an examination of bacterial persistence

Bacterial persistence is a state of metabolic dormancy among a small fraction (<1%) of a genetically identical population of cells that, as a result, becomes transiently resistant to environmental stressors. Such cells, called persisters, are able to survive indeterminate periods of exposure to challenging and even hostile environmental conditions, including nutrient deprivation, oxidative stress, or the presence of an antibiotic to which the bacterium would normally be susceptible. Subpopulations of cells having the persister phenotype is also a common feature of biofilms, in which limited space, hypoxia, and nutrient deficiencies all contribute to the onset of persistence. Microbiologists have been aware of bacterial persistence since the early days of antibiotic development. However, in recent years the significance of this phenomenon has been brought into new focus, as persistent bacterial infections that require multiple rounds of antibiotic treatment are becoming a more widespread clinical challenge. Here, we provide an overview of the major features of bacterial persistence, including the various conditions that precipitate persister formation and a discussion of several of the better-characterized molecular mechanisms that trigger this distinctive mode of bacterial dormancy.

A geostatistical approach to identify and mitigate agricultural nitrous oxide emission hotspots

Anthropogenic emissions of nitrous oxide (N₂O), a trace gas with severe environmental costs, are greatest from agricultural soils amended with nitrogen (N) fertilizer. However, accurate N₂O emission estimates at fine spatial scales are made difficult by their high variability, which represents a critical challenge for the management of N₂O emissions. Here, static chamber measurements (n=60) and soil samples (n=129) were collected at approximately weekly intervals (n=6) for 42-d immediately following the application of N in a southern Minnesota cornfield (15.6-ha), typical of the systems prevalent throughout the U.S. Corn Belt. These data were integrated into a geostatistical model that resolved N₂O emissions at a high spatial resolution (1-m). Field-scale N₂O emissions exhibited a high degree of spatial variability, and were partitioned into three classes of emission strength: hotspots, intermediate, and coldspots. Rates of emission from hotspots were 2-fold greater than non-hotspot locations. Consequently, 36% of the field-scale emissions could be attributed to hotspots, despite representing only 21% of the total field area. Variations in elevation caused hotspots to develop in predictable locations, which were prone to nutrient and moisture accumulation caused by terrain focusing. Because these features are relatively static, our data and analyses indicate that targeted management of hotspots could efficiently reduce field-scale emissions by as much 17%, a significant benefit considering the deleterious effects of atmospheric N₂O.

Data that drive: Closing the loop in the learning hospital system

The learning healthcare system describes a vision of US healthcare that capitalizes on science, information technology, incentives, and care culture to drive improvements in the quality of health care. The inpatient setting, one of the most costly and impactful domains of healthcare, is an ideal setting in which to use data and information technology to foster continuous learning and quality improvement. The rapid digitization of inpatient medicine offers incredible new opportunities to use data from routine care to generate new discovery and thus close the virtuous cycle of learning. We use an object lesson-sepsis care within the 21 hospitals of the Kaiser Permanente Northern California integrated healthcare delivery system-to offer insight into the critical elements necessary for developing a learning hospital system. We then describe how a hospital-wide data-driven approach to inpatient care can facilitate improvements in the quality of hospital care. Journal of Hospital Medicine 2016;11:S11-S17. © 2016 Society of Hospital Medicine.

Oncology supportive care clinics as a novel model to integrate oncology and palliative care

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Background: The integration of oncology with palliative care (PC) has been endorsed by the American Society of Clinical Oncology. Starting in 2012, Kaiser Permanente Northern California (KPNC) began introducing Oncology Supportive Care Clinics (OSCCs) to better provide integrated oncology and PC services. We evaluated the impact of OSCCs on outpatient PC referrals among patients diagnosed with advanced cancers. Methods: We included all adult patients diagnosed with incidental stage IV cancer from 2010-2014 from 19 medical centers within KPNC. We excluded 2 medical centers for inconsistent PC referral tracking. Patients were required to have continuous KPNC coverage during the study period and were followed for a minimum of 12 months after diagnosis or until death. Outcomes included the rate of PC referral following diagnosis and time elapsed from diagnosis to referral. Because the introduction of OSCCs was staggered by medical center, we used a difference-in-differences model to compare the outcomes in medical centers with and without OSCC, before and after OSCC establishment. Results: OSCCs are currently operational at 11 medical centers. A total of 1,7640 patients were included. At centers with OSCCs, the referral rate after OSCC increased from 16.5% to 30.9% (p < 0.01); compared to no change at centers without OSCCs (12.5% before vs. 11.7% after, p = 0.35). There was a decrease in the median time from diagnosis to PC referral at all medical centers, from 163 days (IQR 33-541) to 75 (IQR 20-255) days, p < 0.01, regardless of OSCC presence. Conclusions: The KPNC OSCC model has been successful at increasing PC referrals in patients with stage IV cancers, highlighting the important role healthcare delivery systems have in driving practice change. More research is ongoing to examine patient-centered outcomes associated with receiving OSCC services.

Assessing the utility of an online registry for patients monitoring their own warfarin therapy

AIMS

To evaluate the utility of an online self-report registry for patient self-monitoring and self-management (PSM) of warfarin therapy.

METHODS

A prospective observational study of UK-based patients undertaking PSM and recording their international normalised ratio (INR) data via an online registry. Consenting participants recorded INR test dates, results and warfarin dosages using the online registry for a period of 12 months. Participants reported demographic data, disease characteristics and treatment-related adverse events and provided feedback via a survey. Data accuracy was assessed through comparison of INR results recorded online with results stored on 19 INR testing devices. Percentage time spent within therapeutic time in range (TTR) was also examined.

RESULTS

Eighty-seven per cent (39/45) completed the study period. Age ranged from 26 to 83 years, 44% had undertaken PSM for >5 years. Sixty-six per cent (25/38) reported that the registry was easy to navigate and use. Forty-two participants contributed a total of 1669 INR results. Agreement between self-reported INR results and source INR data was high (99%). Mean TTR was 76% (SD 18.58) with 83% having >60% TTR.

CONCLUSIONS

Findings suggest that an online PSM registry is feasible, accurate and acceptable to patients. These findings require confirmation in a larger cohort of PSM patients. An online self-report registry could provide a valuable resource for gathering real world evidence of clinical effectiveness and safety of these developing models of care.

Merits of random forests emerge in evaluation of chemometric classifiers by external validation

Real-world applications will inevitably entail divergence between samples on which chemometric classifiers are trained and the unknowns requiring classification. This has long been recognized, but there is a shortage of empirical studies on which classifiers perform best in 'external validation' (EV), where the unknown samples are subject to sources of variation relative to the population used to train the classifier. Survey of 286 classification studies in analytical chemistry found only 6.6% that stated elements of variance between training and test samples. Instead, most tested classifiers using hold-outs or resampling (usually cross-validation) from the same population used in training. The present study evaluated a wide range of classifiers on NMR and mass spectra of plant and food materials, from four projects with different data properties (e.g., different numbers and prevalence of classes) and classification objectives. Use of cross-validation was found to be optimistic relative to EV on samples of different provenance to the training set (e.g., different genotypes, different growth conditions, different seasons of crop harvest). For classifier evaluations across the diverse tasks, we used ranks-based non-parametric comparisons, and permutation-based significance tests. Although latent variable methods (e.g., PLSDA) were used in 64% of the surveyed papers, they were among the less successful classifiers in EV, and orthogonal signal correction was counterproductive. Instead, the best EV performances were obtained with machine learning schemes that coped with the high dimensionality (914-1898 features). Random forests confirmed their resilience to high dimensionality, as best overall performers on the full data, despite being used in only 4.5% of the surveyed papers. Most other machine learning classifiers were improved by a feature selection filter (ReliefF), but still did not out-perform random forests.

Endurance exercise training promotes medullary hematopoiesis

Endurance exercise is a poorly defined yet powerful mediator of hematopoiesis. The purpose of this study was to directly investigate the effects of endurance exercise training on hematopoiesis and to identify potential mechanisms responsible for any observed changes. Four-week-old male C57Bl/6 mice were trained on a treadmill at progressive speeds over a 10-wk period. Tissues were harvested 2 d following the final training session. Flow cytometry, the cobblestone area-forming cell assay, and the methycellulose colony-forming unit assay were used to assess medullary and mobilized hematopoietic stem and progenitor cells. Quantitative real-time PCR and Western blots were used to measure hematopoietic cytokine production. Histochemistry was also used to assess adaptations to exercise in the bone marrow niche. Depending on the cell type, endurance training increased medullary and mobilized hematopoietic stem and progenitor cell content from 50 to 800%. Training also reduced marrow cavity fat by 78%. Skeletal muscle hematopoietic cytokine expression was also increased at least 60% by training. Sedentary mice served as controls for the above experiments. In conclusion, endurance exercise training greatly promotes hematopoiesis and does so through improvements in medullary niche architecture as well as increased skeletal muscle hematopoietic cytokine production.

Impacts of woodchip biochar additions on greenhouse gas production and sorption/degradation of two herbicides in a Minnesota soil

A potential abatement to increasing levels of carbon dioxide (CO(2)) in the atmosphere is the use of pyrolysis to convert vegetative biomass into a more stable form of carbon (biochar) that could then be applied to the soil. However, the impacts of pyrolysis biochar on the soil system need to be assessed before initiating large scale biochar applications to agricultural fields. We compared CO(2) respiration, nitrous oxide (N(2)O) production, methane (CH(4)) oxidation and herbicide retention and transformation through laboratory incubations at field capacity in a Minnesota soil (Waukegan silt loam) with and without added biochar. CO(2) originating from the biochar needs to be subtracted from the soil-biochar combination in order to elucidate the impact of biochar on soil respiration. After this correction, biochar amendments reduced CO(2) production for all amendment levels tested (2, 5, 10, 20, 40 and 60% w/w; corresponding to 24-720 tha(-1) field application rates). In addition, biochar additions suppressed N(2)O production at all levels. However, these reductions were only significant at biochar amendment levels >20% w/w. Biochar additions also significantly suppressed ambient CH(4) oxidation at all levels compared to unamended soil. The addition of biochar (5% w/w) to soil increased the sorption of atrazine and acetochlor compared to non-amended soils, resulting in decreased dissipation rates of these herbicides. The recalcitrance of the biochar suggests that it could be a viable carbon sequestration strategy, and might provide substantial net greenhouse gas benefits if the reductions in N(2)O production are lasting.

Electron paramagnetic resonance studies of nitrogen interstitial defects in diamond

We report on electron paramagnetic resonance (EPR) studies of nitrogen doped diamond that has been (15)N enriched, electron irradiated and annealed. EPR spectra from two new nitrogen containing [Formula: see text] defects are detected and labelled WAR9 and WAR10. We show that the properties of these defects are consistent with them being the ⟨001⟩-nitrogen split interstitial and the ⟨001⟩-nitrogen split interstitial-⟨001⟩-carbon split interstitial pair, respectively. We also provide an explanation for why these defects have previously eluded discovery.

Use of quaternized cassia galactomannan for hair conditioning

There is a continuing need for hair care formulas to deliver superior conditioning benefits with highly efficient deposition of hair-enhancing components. In this paper, we describe high-charge-density (3.0 mEq/g) cassia hydroxypropyltrimonium chloride (cassia HPTC), a quaternized galactomannan from the endosperm of Cassia tora and Cassia obtusifolia. Cassia HPTC is shown to participate in the coacervate phase of conditioning shampoos, from which it is deposited onto hair to provide conditioning benefits. Cryo-scanning electron microscopy and time-of-flight secondary ion mass spectrometry were used to observe and characterize the cassia HPTC deposits left on hair. The high-charge-density cassia HPTC resulted in improved deposition efficiency compared with a quaternized guar-containing formula. Cassia HPTC offers benefits as an alternative to traditional cationic polymers as conditioning agents or as an adjunct conditioner to decrease the amount of cationic polymer needed to achieve the desired conditioning performance.

Effects of local continuous release of brain derived neurotrophic factor (BDNF) on peripheral nerve regeneration in a rat model

The purpose of this study was to evaluate the effect of continuously released BDNF on peripheral nerve regeneration in a rat model. Initial in vitro evaluation of calcium alginate prolonged-release-capsules (PRC) proved a consistent release of BDNF for a minimum of 8 weeks. In vivo, a worst case scenario was created by surgical removal of a 20-mm section of the sciatic nerve of the rat. Twenty-four autologous fascia tubes were filled with calcium alginate spheres and sutured to the epineurium of both nerve ends. The animals were divided into 3 groups. In group 1, the fascial tube contained plain calcium alginate spheres. In groups 2 and 3, the fascial tube contained calcium alginate spheres with BDNF alone or BDNF stabilized with bovine serum albumin, respectively. The autocannibalization of the operated extremity was clinically assessed and documented in 12 additional rats. The regeneration was evaluated histologically at 4 weeks and 10 weeks in a blinded manner. The length of nerve fibers and the numbers of axons formed in the tube was measured. Over a 10-week period, axons have grown significantly faster in groups 2 and 3 with continuously released BDNF compared to the control. The rats treated with BDNF (groups 2 and 3) demonstrated significantly less autocannibalization than the control group (group 1). These results suggest that BDNF may not only stimulate faster peripheral nerve regeneration provided there is an ideal, biodegradable continuous delivery system but that it significantly reduces the neuropathic pain in the rat model.

Hydrogen incorporation in diamond: the nitrogen-vacancy-hydrogen complex

We report the identification of the nitrogen-vacancy-hydrogen complex in a freestanding nitrogen-doped isotopically engineered single crystal diamond synthesized by chemical vapor deposition. The hydrogen atom is located in the vacancy of a nearest-neighbor nitrogen-vacancy defect and appears to be bonded to the nitrogen atom maintaining the trigonal symmetry of the center. The defect is observed by electron paramagnetic resonance in the negative charge state in samples containing a suitable electron donor (e.g., substitutional nitrogen N(0)(S)).