Cost-Effectiveness of Sleep Apnea Diagnosis and Treatment in Hospitalized Persons With Moderate to Severe Traumatic Brain Injury

OBJECTIVE

To assess the cost-effectiveness of alternative approaches to diagnose and treat obstructive sleep apnea (OSA) in patients with traumatic brain injury (TBI) during inpatient rehabilitation.

SETTING

Data collected during the Comparison of Sleep Apnea Assessment Strategies to Maximize TBI Rehabilitation Participation and Outcome (C-SAS) clinical trial (NCT03033901) on an inpatient rehabilitation TBI cohort were used in this study.

STUDY DESIGN

Decision tree analysis was used to determine the cost-effectiveness of approaches to diagnosing and treating sleep apnea. Costs were determined using 2021 Centers for Medicare and Medicaid Services reimbursement codes. Effectiveness was defined in terms of the appropriateness of treatment. Costs averted were extracted from the literature. A sensitivity analysis was performed to account for uncertainty. Analyses were performed for all severity levels of OSA and a subgroup of those with moderate to severe OSA. Six inpatient approaches using various phases of screening, testing, and treatment that conform to usual care or guideline-endorsed interventions were evaluated: (1) usual care; (2) portable diagnostic testing followed by laboratory-quality testing; (3) screening with the snoring, tiredness, observed apnea, high BP, BMI, age, neck circumference, and male gender (STOP-Bang) questionnaire; (4) Multivariable Apnea Prediction Index (MAPI) followed by portable diagnostic testing and laboratory-quality testing; (5) laboratory-quality testing for all; and (6) treatment for all patients.

MAIN MEASURES

Cost, Effectiveness, and Incremental Cost-Effectiveness Ratio (ICER).

RESULTS

Phased approaches utilizing screening and diagnostic tools were more effective in diagnosing and allocating treatment for OSA than all alternatives in patients with mild to severe and moderate to severe OSA. Usual care was more costly and less effective than all other approaches for mild to severe and moderate to severe OSA.

CONCLUSIONS

Diagnosing and treating OSA in patients with TBI is a cost-effective strategy when compared with usual care.

Search for a Dark-Matter-Induced Cosmic Axion Background with ADMX

We report the first result of a direct search for a cosmic axion background (CaB)-a relativistic background of axions that is not dark matter-performed with the axion haloscope, the Axion Dark Matter eXperiment (ADMX). Conventional haloscope analyses search for a signal with a narrow bandwidth, as predicted for dark matter, whereas the CaB will be broad. We introduce a novel analysis strategy, which searches for a CaB induced daily modulation in the power measured by the haloscope. Using this, we repurpose data collected to search for dark matter to set a limit on the axion photon coupling of a CaB originating from dark matter cascade decay via a mediator in the 800-995 MHz frequency range. We find that the present sensitivity is limited by fluctuations in the cavity readout as the instrument scans across dark matter masses. Nevertheless, we suggest that these challenges can be surmounted using superconducting qubits as single photon counters, and allow ADMX to operate as a telescope searching for axions emerging from the decay of dark matter. The daily modulation analysis technique we introduce can be deployed for various broadband rf signals, such as other forms of a CaB or even high-frequency gravitational waves.

COPING WITH CHRONIC PAIN AFTER TRAUMATIC BRAIN INJURY: ROLE OF RACE/ETHNICITY AND IMPACT ON PARTICIPATION OUTCOMES IN A TBI MODEL SYSTEMS SAMPLE

OBJECTIVE

To investigate catastrophizing and self-efficacy for managing pain among Non-Hispanic Whites, Non-Hispanic Blacks, and Hispanics with chronic pain after traumatic brain injury (TBI), and whether coping interacts with race/ethnicity to predict participation outcomes.

SETTING

Community after discharge from inpatient rehabilitation.

PARTICIPANTS

621 individuals with moderate to severe TBI and chronic pain, who completed follow-up as part of a national longitudinal study of TBI and also participated in a collaborative study on chronic pain.

DESIGN

Multicenter, cross-sectional, survey study.

MAIN MEASURES

Catastrophizing subscale from the Coping With Pain Scale; Pain Self-Efficacy Questionnaire; Participation Assessment With Recombined Tools-Objective.

RESULTS

After controlling for relevant sociodemographic variables, a significant interaction was observed between race/ethnicity and insurance status, such that Blacks who had public health insurance reported greater catastrophizing in response to pain compared with Whites. Race/ethnicity and self-efficacy for managing pain were unrelated. Greater catastrophizing was associated with lower participation but did not interact with race/ethnicity. Blacks reported lower participation relative to Whites, independent of catastrophizing.

CONCLUSIONS

Black individuals who have TBI and chronic pain, and who have public insurance, may be vulnerable to difficulties managing pain. They are more likely to cope by catastrophizing, and catastrophizing is related to worse participation outcomes. The results suggest that access to care may affect response to chronic pain after TBI.

0632 Early sleep-disordered breathing in moderate-to-severe traumatic brain injury (TBI) is linked with chronic pain status at long-term follow-up: A TBI Model Systems study

Introduction

Sleep disorders and chronic pain (pain of >3 months duration) are common after traumatic brain injury (TBI). A recently completed multi-center trial found that two-thirds of adults with moderate-to-severe TBI had sleep apnea diagnosed during polysomnography (PSG) completed during inpatient rehabilitation. Although a bidirectional relationship between sleep and pain exists, attention to sleep apnea as a specific diagnosis and its possible role in chronic pain following TBI has not been explored. We hypothesized that PSG-derived respiratory indices shortly following TBI would be worse among those reporting chronic pain at 1- to 2-year follow-up compared to those without chronic pain.

Methods

Sample (N=66) derived from overlapping cohorts across two separate multicenter studies. Participants with moderate to severe TBI underwent PSG during inpatient rehabilitation and completed a telephone follow-up interview to assess chronic pain status using standardized measures at 1-2 years post-TBI (610-day average). Pairwise comparisons across participants with and without chronic pain were made to determine the magnitude of clinically significant differences on respiratory indices including oxygen desaturation, central and obstructive apneas, and total apnea-hypopnea index (AHI).

Results

Presence of chronic pain at follow-up was associated with elevated central apnea events (2.6) and oxygen desaturation (19.6) relative to those without chronic pain (0.8 and 7.9, respectively). Important differences were also seen between obstructive and total apnea hypopnea index (AHI) using Centers for Medicaid and Medicare Services scoring criteria, with those in the chronic pain cohort being 6.5 and 8.7 points higher than their non-pain counterparts, respectively. Group differences on obstructive and total AHI were considered minor when using the American Academy of Sleep Medicine scoring criteria, although those with current pain experienced categorically worse sleep apnea (total AHI = 19 versus 12.4).

Conclusion

This is the first study to find an association between PSG-derived respiratory indices and long-term chronic pain status following moderate-to-severe TBI. Sleep apnea represents an important modifiable factor following injury that may contribute to long-term pain-related outcomes. Given the prominence of chronic pain several years post injury, future studies should investigate the role of sleep apnea and early intervention among those following moderate-to-severe TBI to determine impact on long-term rehabilitation and pain outcomes.

Support (If Any)

PCORI; CER-1511-33005); VA TBI Model Systems Program of Research; GDIT; NIDILRR 90DPTB0008. Clinicaltrial.gov Registration Number: NCT03033901.

Search for Invisible Axion Dark Matter in the 3.3-4.2 μeV Mass Range

We report the results from a haloscope search for axion dark matter in the 3.3-4.2  μeV mass range. This search excludes the axion-photon coupling predicted by one of the benchmark models of "invisible" axion dark matter, the Kim-Shifman-Vainshtein-Zakharov model. This sensitivity is achieved using a large-volume cavity, a superconducting magnet, an ultra low noise Josephson parametric amplifier, and sub-Kelvin temperatures. The validity of our detection procedure is ensured by injecting and detecting blind synthetic axion signals.

Scoping Review of Opioid Use After Traumatic Brain Injury

OBJECTIVE

To summarize the current literature to identify what research has been conducted, examine the approaches used, and determine what is presently known about prescription and nonprescription opioid receipts and use among individuals with traumatic brain injury (TBI).

DATA SOURCES

The search strategy included the following: opioid; opiate; analgesics, opioid; opiate alkaloids; or opioid-related disorders; AND brain injury; brain injuries; brain injuries, traumatic; head injury; head injuries; head injuries, closed; head injuries, penetrating; brain concussion; diffuse axonal injury; diffuse axonal injuries; brain trauma/s; head trauma/s; concussion; craniocerebral trauma/s; or TBI. Filters included English and Adults (19+ years). Study Selection: Inclusion: English language, adults with stable TBI, and prescription opioid receipt or use after TBI. Exclusion: Animal models, populations with other acquired brain injury, acute TBI management, and non-peer-reviewed articles, theses, or conference abstracts. Multiple reviewers screened abstracts and full-text articles for eligibility. In total, 771 abstracts were screened, 183 full texts were reviewed, and 21 met eligibility criteria. Data Extraction: Relevant content was independently extracted by multiple observers, including authors, design, sample identification and data source/s, TBI severity, TBI assessment, opioid assessment, study population (demographics, N), military affiliation, comparison groups, date of data collection, and summary of findings.

RESULTS

Studies were published between 1987 and 2019; most data were collected prior to 2015. The majority utilized administrative and electronic medical record data from the Department of Veterans Affairs and retrospective cohort designs, and most focused on prescription opioids. There were no studies evaluating interventions to reduce use of opioids in TBI populations. Preliminary findings suggest that prescription opioid receipt is strongly related to psychological symptoms, including comorbid depression, anxiety, and posttraumatic stress disorder.

CONCLUSIONS

Despite increased awareness of opioid receipt and use following TBI, there is limited investigation on the examination of this issue. Future studies should include more varied patient populations as well as evaluate interventions to reduce opioid use following TBI.

Correlates of sleep disturbance in Veterans with traumatic brain injury and chronic pain: A cross-sectional study

BACKGROUND

Few studies have investigated sleep in Veterans with comorbid traumatic brain injury (TBI) and chronic pain.

OBJECTIVE

To describe mood and cognitive correlates with sleep disturbance in a sample of Veterans with both TBI and chronic pain.

RESEARCH METHOD

Cross-sectional, correlational analyses were completed using baseline data from a randomized controlled trial comparing psychosocial treatments for pain in Veterans with TBI. Enrollment occurred between July 2015 and January 2017. Self-report measures of hours slept, insomnia severity, depression and PTSD symptoms were collected along with a brief neuropsychological assessment.

RESULTS

Participants (n = 221) were an average age of 37.2 years (SD = 8.2) and mostly male (89%). Participants reported sleeping an average of 4.9 h a night (SD = 1.4) with an average Insomnia Severity Index (ISI) score of 17.4 (SD = 5.4) suggesting moderate insomnia symptoms. Fewer hours slept was associated with higher depression scores (r = -0.28, p < 0.001) and slower processing speed (r = 0.23, p < 0.001). Increasing insomnia severity was associated with greater depression (r = 0.57, p < 0.001) and PTSD symptoms (r = 0.44, p < 0.001), and slower processing speed (r = -0.22, p < 0.001).

CONCLUSIONS

The average ISI score was above the clinical cut off for insomnia diagnosis. Results suggest that those with more severe insomnia symptoms report higher depression and PTSD symptoms as well as exhibit slower processing speed. Improving sleep in this population may be important for improving outcome following TBI.

Implementation of Complex Interventions: Lessons Learned From the Patient-Centered Outcomes Research Institute Transitional Care Portfolio

BACKGROUND

Despite the well-documented risks to patient safety associated with transitions from one care setting to another, health care organizations struggle to identify which interventions to implement. Multiple strategies are often needed, and studying the effectiveness of these complex interventions is challenging.

OBJECTIVE

The objective of this study was to present lessons learned in implementing and evaluating complex transitional care interventions in routine clinical care.

RESEARCH DESIGN

Nine transitional care study teams share important common lessons in designing complex interventions with stakeholder engagement, implementation, and evaluation under pragmatic conditions (ie, using only existing resources), and disseminating findings in outlets that reach policy makers and the people who could ultimately benefit from the research.

RESULTS

Lessons learned serve as a guide for future studies in 3 areas: (1) Delineating the function (intended purpose) versus form (prespecified modes of delivery of the intervention); (2) Evaluating both the processes supporting implementation and the impact of adaptations; and (3) Engaging stakeholders in the design and delivery of the intervention and dissemination of study results.

CONCLUSION

These lessons can help guide future pragmatic studies of care transitions.

806 Barriers to screening and diagnosis of obstructive sleep apnea during inpatient traumatic brain injury rehabilitation

Introduction

Obstructive Sleep Apnea (OSA) is prevalent after moderate to severe traumatic brain injury (TBI) and may diminish recovery when left untreated. Despite the demonstrated importance of treating OSA following TBI, assessment for OSA during or soon after inpatient rehabilitation for TBI is limited. Little is known about barriers to implementing OSA screening and early diagnosis during inpatient rehabilitation thus hindering the translation of evidence-based OSA assessment procedures into clinical practice and potentially delaying necessary OSA treatment. The current analysis explored facilitators and barriers to implementing OSA screening tools in an inpatient rehabilitation setting from the perspectives of end user stakeholders.

Methods

Patients, families, industry, clinical providers and administrators participated in a two-day meeting following completion of a diagnostic clinical trial of OSA screening and diagnostic tools during inpatient rehabilitation. Stakeholders were provided with open ended questions generated by study investigators and given the opportunity to respond on paper or a “graffiti wall” (i.e., white board). Example questions include “What are the greatest needs of the healthcare system related to sleep apnea and TBI?” and “What are the key things we need to consider to move results into real-world practice?” Qualitative content analyses using a rapid matrix approach were conducted from stakeholder feedback obtained during the two-day meeting, which included a guided review of emerging OSA research and discussion of potential implementation barriers of OSA assessment during inpatient rehabilitation.

Results

Improved screening and treatment practices for OSA were the greatest needs identified. To meet these needs, stakeholders identified the importance of improving patient, family, and staff understanding of OSA (e.g., health literacy) and other sleep disorders through education; inpatient rehabilitation access to resources (technology; sleep providers); and reimbursement for additional inpatient procedures.

Conclusion

Although treatment of OSA is crucial for recovery during inpatient rehabilitation following TBI, barriers to earlier recognition, diagnosis, and treatment of OSA exists across several different domains, including education, resources, and funding policies. Findings support future implementation efforts to translate evidence-based care into practice to improve patient outcomes.

Support (if any)

PCORI-NCT03033901

Toward Improving the Prediction of Functional Ambulation After Spinal Cord Injury Though the Inclusion of Limb Accelerations During Sleep and Personal Factors

OBJECTIVE

To determine if functional measures of ambulation can be accurately classified using clinical measures; demographics; personal, psychosocial, and environmental factors; and limb accelerations (LAs) obtained during sleep among individuals with chronic, motor incomplete spinal cord injury (SCI) in an effort to guide future, longitudinal predictions models.

DESIGN

Cross-sectional, 1-5 days of data collection.

SETTING

Community-based data collection.

PARTICIPANTS

Adults with chronic (>1 year), motor incomplete SCI (N=27).

INTERVENTIONS

Not applicable.

MAIN OUTCOME MEASURES

Ambulatory ability based on the 10-m walk test (10MWT) or 6-minute walk test (6MWT) categorized as nonambulatory, household ambulator (0.01-0.44 m/s, 1-204 m), or community ambulator (>0.44 m/s, >204 m). A random forest model classified ambulatory ability using input features including clinical measures of strength, sensation, and spasticity; demographics; personal, psychosocial, and environmental factors including pain, environmental factors, health, social support, self-efficacy, resilience, and sleep quality; and LAs measured during sleep. Machine learning methods were used explicitly to avoid overfitting and minimize the possibility of biased results.

RESULTS

The combination of LA, clinical, and demographic features resulted in the highest classification accuracies for both functional ambulation outcomes (10MWT=70.4%, 6MWT=81.5%). Adding LAs, personal, psychosocial, and environmental factors, or both increased the accuracy of classification compared with the clinical/demographic features alone. Clinical measures of strength and sensation (especially knee flexion strength), LA measures of movement smoothness, and presence of pain and comorbidities were among the most important features selected for the models.

CONCLUSIONS

The addition of LA and personal, psychosocial, and environmental features increased functional ambulation classification accuracy in a population with incomplete SCI for whom improved prognosis for mobility outcomes is needed. These findings provide support for future longitudinal studies that use LA; personal, psychosocial, and environmental factors; and advanced analyses to improve clinical prediction rules for functional mobility outcomes.

0606 Comparative Effectiveness of Sleep Apnea Screening Tools During Inpatient Rehabilitation for Moderate to Severe TBI

Introduction

Recent studies highlight prevalent obstructive sleep apnea after moderate to severe TBI during a time of critical neural repair. The purpose of this study is to determine the diagnostic sensitivity, specificity and comparative effectiveness of traditional sleep apnea screening tools in TBI neurorehabilitation admissions.

Methods

This is a prospective diagnostic comparative effectiveness trial of sleep apnea screening tools (STOPBANG, Berlin, MAPI [Multi-Apnea Prediction Index]) relative Level 1 polysomnography at six TBI Model System Inpatient Rehabilitation Centers. Between 05/2017 and 02/2019, 449 of 896 screened were eligible for the trial with 345 consented (77% consented). Additional screening left 263 eligible for and completing polysomnography with final analyses completed on 248. The primary outcome was the Area Under the Curve (AUC) of screening tools relative to total apnea hypopnea index ≥15 (AHI, moderate to severe apnea) measured at a median of 47 days post-TBI (IQR 29-47).

Results

Participants were primarily young to middle age (AGE IQR 28,40,59), male (81%), white (74%), and had primarily severe TBI (IQR GCS 3,6,14). A subset (26%) had a history of military service. Results revealed that the Berlin high risk score (ROC-AUC=0.63) was inferior to the MAPI (ROC-AUC = 0.7802) (p=.0211, CI: 0.0181, 0.2233) and STOPBANG (ROCAUC = 0.7852) (p=.0006, CI: 0.0629, 0.2302); both of which had comparable AUC (p=.7245, CI: -0.0472, 0.0678). Findings were similar for AHI≥30 (severe apnea); however, no differences across scales was observed at AHI&gt;5. The pattern was similar across TBI severity subgroups except for delirium or post-traumatic amnesia status wherein the MAPI outperformed the Berlin and STOPBANG. Youden’s Index to determine risk yielded lower sensitivities but higher specificities relative to non-TBI samples.

Conclusion

This study is the first to provide clinicians with data to support a choice for which sleep apnea screening tools are more effective during inpatient rehabilitation for moderate to severe TBI (STOPBANG, MAPI vs Berlin) to help reduce comorbidity and possibly improve neurologic outcome.

Support

PCORI (CER-1511-33005), GDHS (W91YTZ-13-C-0015; HT0014-19-C-0004)) for DVBIC, NIDILRR (NSDC Grant # 90DPTB00070, #90DP0084, 90DPTB0013-01-00, 90DPTB0008, 90DPT80004-02).

Use of Amitriptyline in the Treatment of Headache After Traumatic Brain Injury: Lessons Learned From a Clinical Trial

OBJECTIVES

The primary outcome of this study was to assess the efficacy and safety of preventive treatment with amitriptyline on headache frequency and severity after mild traumatic brain injury (mTBI).

BACKGROUND

Despite the fact that headache is the most common and persistent physical symptom after TBI, there has been little research on the longitudinal course or pharmacologic treatment of this disorder. Of those who have headache after injury, about 60% continue to complain of headache at 3 months post injury, with higher levels of disability than those without headache. There have been no prospective, randomized, controlled trials of a pharmacologic agent for headache after TBI. Additionally, a brain-injured population may be more susceptible to side effects of medication.

DESIGN

This is a single-center phase II trial of amitriptyline to prevent persistent headache after an mTBI. Medication dose was gradually increased from 10 to 50 mg daily.

RESULTS

Fifty participants were enrolled and 33 who completed the 90-day assessment were included in the final analysis. In order to detect a possible cognitive impact of the study drug, 24 participants were randomly assigned to start amitriptyline immediately after study enrollment and 26 were assigned to start 30 days after enrollment. Forty-nine percent (18/37) of those assigned to take medication took none throughout the study period, with less compliance in younger participants with mean ages of 32.7 in those who did not take any medication, 33.4 who were less than 80% compliant, and 42.3 who were compliant (P = .013). Compliance in keeping a daily headache diary was low, with 29/50 participants (58%) meeting daily entry completion, and only 10 participants maintaining 100% diary completion. No differences were found between those who started medication immediately vs at day 30 in headache frequency or severity.

CONCLUSIONS

While headache is the most common symptom following mTBI, current evidence does not support a specific treatment. No differences were noted in headache frequency compared to our prior study. However, the current sample had significantly lower headache severity (15% vs 36% with pain rating of 6 or above, P = .015) compared to our prior study. Our current study was not able to determine whether there is any benefit for the use of amitriptyline as a headache preventive because of difficulty with study recruitment and compliance. The challenges with recruitment and retention in the mTBI population were instructive, and future research in this area will need to identify strategies to improve recruitment, diary compliance, and medication adherence in this population.

Abstract P3-14-07: Evaluation of the effects of talazoparib on QT interval prolongation

Background: Talazoparib (TAL), an oral poly ADP-ribose polymerase inhibitor, is under investigation in multiple oncologic clinical trials and has been submitted to the US FDA for use in patients (pts) with germline BRCA-mutated, HER2-negative advanced breast cancer.

International Conference on Harmonisation guidance recommends all new drugs be evaluated for effects on cardiac repolarization in a well-controlled clinical study. For drugs for which such evaluation cannot be conducted in healthy volunteers (eg, most anticancer agents), collection of robust corrected QT (QTc) interval data from a dedicated QTc study (hybrid thorough QT/QTc study) in pts is required in the registration dossier. The effect of steady-state (ss) TAL (1 mg once daily) on cardiac repolarization in pts with advanced solid tumors was evaluated in an open-label phase 1 study (NCT03042910).

Methods: Continuous 12-lead electrocardiogram (ECG) recordings were collected at baseline (Day -1); time-matched pharmacokinetic (PK) samples and continuous ECG recordings were obtained on Days 1, 2, and 22 (when TAL concentrations achieved ss). On Day -1, pts had continuous 12-lead ECG recording starting at Time 0 (Day 1 dosing time) for 6 hrs. On Days 1 and 22, ECG recording started 45 min before TAL administration and continued for 6 hrs post dose and blood samples for PK were collected before dose and at 1, 2, 4, and 6 hrs post dose. On Day 2, a 30-min ECG recording and a PK sample were obtained before dose at Time 0.

Continuous ECG recordings were submitted to a central laboratory; triplicate 10-sec ECGs were extracted from a 5-min extraction window beginning 15 min before each PK collection time. ECG measurements were reported via blinded manual adjudication process and included PR interval, QT interval, RR interval, and QRS complex. The QT interval was corrected for effect of heart rate using Fridericia's correction (QTcF) and Bazett's correction (QTcB).

The estimate of change from time-matched baseline and its 2-sided 90% confidence interval (CI) was calculated for each nominal time point using PROC MEANS. Additionally, a prespecified PK/pharmacodynamic (PD) model was used to describe the relationship between plasma TAL concentrations ([TAL]) and QTc. The prespecified linear mixed-effects model included [TAL], time (categorical), and treatment with random pt effects on [TAL] and the intercept. If the upper bounds (UB) of 1-sided 95% CIs of time-matched ΔQTc for all ECG time points were &lt;20 msec and the UB of 1-sided 95% CIs of the predicted ΔQTc at the mean ss maximum [TAL] was &lt;20 msec, the effect of TAL on QTc was not of clinical relevance.

Results: 37 of 38 pts enrolled received TAL and were included in the ECG and PK/PD analyses. No pts had a postbaseline absolute maximum QTcF or QTcB ≥500 msec or ΔQTc ≥60 msec. The UB of the 1-sided 95% CI for the time-matched ΔQTcF and ΔQTcB were &lt;12 msec at all nominal ECG time points. In the PK/PD analysis, the slopes (95% CI) of QTcF-[TAL] and QTcB-[TAL] relationships were -0.14 (-0.78 to 0.50) msec/ng/mL and -0.24 (-0.88 to 0.41) msec/ng/mL, respectively, indicating that TAL did not have a concentration-dependent effect on QTcF or QTcB.

Conclusion: TAL does not have a clinically relevant effect on QTc.

Funding: Medivation LLC, acquired by Pfizer.

Citation Format: Hoffman J, Chakrabarti J, Wainberg ZA, Plotka A, Babu S, Milillo Naraine A, Kanamori D, Moroose R, Nguyen L, Wang D. Evaluation of the effects of talazoparib on QT interval prolongation [abstract]. In: Proceedings of the 2018 San Antonio Breast Cancer Symposium; 2018 Dec 4-8; San Antonio, TX. Philadelphia (PA): AACR; Cancer Res 2019;79(4 Suppl):Abstract nr P3-14-07.

Bone density and asymmetry are not related to DDT in House Sparrows: Insights from micro-focus X-ray computed tomography

In organisms, DDT (Dichlorodiphenyltrichloroethane) and its metabolites, DDE (Dichlorodiphenyldichloroethylene) and DDD (Dichlorobischlorophenylethane) are endocrine mimics. They can influence bone density and other bone structural features. This study was conducted on House Sparrows (Passer domesticus) caught from the Free State - and the Limpopo Provinces of South Africa (SA). The sites were chosen based on spraying patterns of DDT for malaria control or non-spraying. The bone mineral densities of the femurs as well as the lengths of the left- and right leg bones were determined using micro-focus X-ray computed tomography (μ-XCT). The concentrations of DDT and its metabolites in the liver were determined with gas-chromatography mass-spectrometry to provide baseline concentrations of DDT in the body, allowing comparison of the various groups of birds. There was no asymmetry between the lengths of the bones of the left- and the right legs. DDT concentrations in the liver did not correlate with bone lengths. In addition, there were no significant differences between the relative densities of the left- and right leg bones with increase of concentrations of DDT. The concentrations of DDT and its metabolites did not have a significant effect on the measured bone parameters of House Sparrows. It is possible that the concentrations of DDT and its metabolites in the environments were too low to be injurious to the birds and/or tolerance to the insecticide has developed in the birds over more than six decades of almost continuous application of DDT.

Observation of Fine Time Structures in the Cosmic Proton and Helium Fluxes with the Alpha Magnetic Spectrometer on the International Space Station

We present the precision measurement from May 2011 to May 2017 (79 Bartels rotations) of the proton fluxes at rigidities from 1 to 60 GV and the helium fluxes from 1.9 to 60 GV based on a total of 1×10^{9} events collected with the Alpha Magnetic Spectrometer aboard the International Space Station. This measurement is in solar cycle 24, which has the solar maximum in April 2014. We observed that, below 40 GV, the proton flux and the helium flux show nearly identical fine structures in both time and relative amplitude. The amplitudes of the flux structures decrease with increasing rigidity and vanish above 40 GV. The amplitudes of the structures are reduced during the time period, which started one year after solar maximum, when the proton and helium fluxes steadily increase. Above ∼3  GV the p/He flux ratio is time independent. We observed that below ∼3  GV the ratio has a long-term decrease coinciding with the period during which the fluxes start to rise.

Multimodal Characterization of the Late Effects of Traumatic Brain Injury: A Methodological Overview of the Late Effects of Traumatic Brain Injury Project

Epidemiological studies suggest that a single moderate-to-severe traumatic brain injury (TBI) is associated with an increased risk of neurodegenerative disease, including Alzheimer's disease (AD) and Parkinson's disease (PD). Histopathological studies describe complex neurodegenerative pathologies in individuals exposed to single moderate-to-severe TBI or repetitive mild TBI, including chronic traumatic encephalopathy (CTE). However, the clinicopathological links between TBI and post-traumatic neurodegenerative diseases such as AD, PD, and CTE remain poorly understood. Here, we describe the methodology of the Late Effects of TBI (LETBI) study, whose goals are to characterize chronic post-traumatic neuropathology and to identify in vivo biomarkers of post-traumatic neurodegeneration. LETBI participants undergo extensive clinical evaluation using National Institutes of Health TBI Common Data Elements, proteomic and genomic analysis, structural and functional magnetic resonance imaging (MRI), and prospective consent for brain donation. Selected brain specimens undergo ultra-high resolution ex vivo MRI and histopathological evaluation including whole-mount analysis. Co-registration of ex vivo and in vivo MRI data enables identification of ex vivo lesions that were present during life. In vivo signatures of postmortem pathology are then correlated with cognitive and behavioral data to characterize the clinical phenotype(s) associated with pathological brain lesions. We illustrate the study methods and demonstrate proof of concept for this approach by reporting results from the first LETBI participant, who despite the presence of multiple in vivo and ex vivo pathoanatomic lesions had normal cognition and was functionally independent until her mid-80s. The LETBI project represents a multidisciplinary effort to characterize post-traumatic neuropathology and identify in vivo signatures of postmortem pathology in a prospective study.

Rehospitalization Over 10 Years Among Survivors of TBI: A National Institute on Disability, Independent Living, and Rehabilitation Research Traumatic Brain Injury Model Systems Study

OBJECTIVE

To describe the rates and causes for rehospitalization over 10 years after moderate-severe traumatic brain injury (TBI), and to characterize longitudinal trajectories of the probability of rehospitalization using generalized linear mixed models and individual growth curve models conditioned on factors that help explain individual variability in rehospitalization risk over time.

DESIGN

Secondary analysis of data from a multicenter longitudinal cohort study.

SETTING

Acute inpatient rehabilitation facilities and community follow-up.

PARTICIPANTS

Individuals 16 years and older with a primary diagnosis of TBI.

MAIN OUTCOME MEASURES

Rehospitalization (and reason for rehospitalization) as reported by participants or proxy during follow-up telephone interviews at 1, 2, 5, and 10 years postinjury.

RESULTS

The greatest number of rehospitalizations occurred in the first year postinjury (27.8% of the sample), and the rates of rehospitalization remained largely stable (22.1%-23.4%) at 2, 5, and 10 years. Reasons for rehospitalization varied over time: Orthopedic and reconstructive surgery rehospitalizations were most common in year 1, whereas general health maintenance was most common by year 2 with rates increasing at each follow-up. Longitudinal models indicate that multiple demographic and injury-related factors are associated with the probability of rehospitalization over time.

CONCLUSIONS

These findings can inform the content and timing of interventions to improve health and longevity after TBI.

Abstract P5-21-23: Evaluation of the drug interaction potential of palbociclib and exemestane – Results from the PEARL pharmacokinetic sub-Study

Background: Palbociclib (PAL) is an oral cyclin-dependent kinase (CDK) 4/6 inhibitor that is under investigation in multiple oncologic clinical trials and is currently approved for use in combination with aromatase inhibitors (AIs) or fulvestrant (FUL) in patients with hormone receptor positive (HR+), human epidermal growth factor receptor 2 negative (HER2–) advanced breast cancer (BC).

The PEARL Study is an ongoing international, open label, controlled, randomized Phase 3 study comparing the efficacy and safety of PAL in combination with endocrine therapy (exemestane [EXE] or FUL) versus capecitabine in postmenopausal women with HR+/ HER2– metastatic BC whose disease progressed on AIs. A secondary objective of the study was to evaluate the pharmacokinetics (PK) of PAL (125mg QD, 3 weeks on/1 week off) and EXE (25mg QD, continuously) when coadministered. This is the first study to investigate the drug-drug interaction (DDI) potential of the combination of PAL and the AI EXE.

Methods: Patients (pts) randomized to the PAL+EXE arm of the PEARL Study in seven selected sites had the option of participating in the PK sub-study. Those who enrolled in the PK sub-study received EXE alone in a 7-day lead-in period immediately prior to Cycle 1 Day 1, when both drugs were coadministered on their standard dosing regimens. Sub-study pts were to have 2 pre-dose plasma PK samples drawn at steady-state (ss) during the lead-in period ("EXE Alone") for EXE determination, and 2 ss PK samples drawn for EXE and PAL determination (2 per analyte) during coadministration ("PAL+EXE"). Plasma concentrations of PAL and EXE were measured using validated liquid chromatography-tandem mass spectrometry (LC-MS/MS) methods. The withinpatient mean concentration of the PK samples which met ss acceptance criteria (WPM-Ctrough) for each analyte were generated for each treatment period as the input for DDI analyses.

To assess the effect of coadministration of PAL on EXE PK, the WPM-Ctrough of EXE was compared within patients between the "PAL+EXE" (Test) and "EXE Alone" (Reference) treatment periods using a one-way analysis of variance (ANOVA) model with treatment as a fixed effect and patient as a random effect. To assess the effect of coadministration of EXE on PAL PK, the WPM-Ctrough of PAL was compared between the "PAL+EXE" period (Test) and historical data (Reference) using an ANOVA model. Analysis of covariance (ANCOVA) models were used to assess the impact of demographic differences between analysis populations in covariates known to impact PAL PK on the ANOVA model conclusions.

Results: A total of 26 pts randomized to the PAL+EXE arm were enrolled in the PK sub-study and had PK samples analysed, of which 23 meet ss acceptance criteria. The ratio of the adjusted geometric means for EXE WPM-Ctrough was 106.9% (90%CI: 82.4-138.8), when EXE was administered with PAL, compared with its administration alone. Likewise, the models to assess potential for EXE to perpetrate DDI on PAL PK showed ratios of adjusted geometric means of 102.4% (90%CI: 82.0-127.9) and 111.6% (90%CI: 90.3137.8), when adjusted for covariates.

Conclusion: The PK data indicate a lack of a clinically meaningful DDI between PAL and EXE when the 2 drugs are coadministered.

Sponsor: GEICAM

Citation Format: Martín M, Hoffman J, Ruiz-Borrego M, Muñoz M, Calvo L, Crownover P, García-Sáenz JA, Alba E, Wang D, Thallinger C, Stradella A, Montaño Á, Adamo B, Antolín S, Moreno-Antón F, Falo C, Ruiz V, Martín N, Caballero R, Carrasco E, Gil-Gil M. Evaluation of the drug interaction potential of palbociclib and exemestane – Results from the PEARL pharmacokinetic sub-Study [abstract]. In: Proceedings of the 2017 San Antonio Breast Cancer Symposium; 2017 Dec 5-9; San Antonio, TX. Philadelphia (PA): AACR; Cancer Res 2018;78(4 Suppl):Abstract nr P5-21-23.

Observation of the Identical Rigidity Dependence of He, C, and O Cosmic Rays at High Rigidities by the Alpha Magnetic Spectrometer on the International Space Station

We report the observation of new properties of primary cosmic rays He, C, and O measured in the rigidity (momentum/charge) range 2 GV to 3 TV with 90×10^{6} helium, 8.4×10^{6} carbon, and 7.0×10^{6} oxygen nuclei collected by the Alpha Magnetic Spectrometer (AMS) during the first five years of operation. Above 60 GV, these three spectra have identical rigidity dependence. They all deviate from a single power law above 200 GV and harden in an identical way.