A 65-Year-Old Man With Back Pain and Imaging Findings of Spinal Cord Compression

Spinal cord compression is a potentially devastating consequence of cancer. Early recognition of the signs and symptoms permit diagnosis prior to the development of irreversible neurological damage. This complication occurs in 5% to 10% of patients with malignancy, often at the end stages of the patient's illness; however, it can be the presenting manifestation of malignancy in up to 23% of patients. With the advances in surgical, radiation, and medical oncology approaches, the outcomes of patients with malignant spinal cord compression continue to improve. We discuss the case of a previously healthy man, aged 65 years, who presented with back pain and large T8 spinal mass, leading to a diagnosis of multiple myeloma with spinal cord compromise.

Risk factors for pregnancy-associated venous thromboembolism in Singapore

OBJECTIVES

Pregnancy-associated venous thromboembolism (VTE), including deep venous thrombosis (DVT) and pulmonary embolism (PE), is associated with increased risk of maternal mortality and morbidity. This study aimed to assess potential risk factors for pregnancy-associated VTE.

METHODS

In this case-control study, women with pregnancy-associated VTE were identified via International Classification of Diseases codes and included if they had been objectively diagnosed with VTE during pregnancy or within six weeks postpartum, from 2004 to 2016, at KK Women's and Children's Hospital or Singapore General Hospital in Singapore. Controls, i.e. pregnant women without VTE, were selected from a prospective longitudinal study. The odds ratio (OR) for VTE was computed for a range of maternal and obstetric factors.

RESULTS AND CONCLUSIONS

From 2004 to 2016, 89 cases of pregnancy-associated VTE and 926 controls were identifed and analysed using logistic regression. The most significant risk factors for pregnancy-associated VTE were smoking (OR 5.44, p=0.0002) and preterm delivery (OR 5.06, p=0.023). Malay race, multiparity, non-O blood group and caesarean section, were also identified to be of higher risk. These risk factors should be useful in the development of thromboprophylaxis strategies for pregnancy and the postpartum period, especially in Singapore.

Reliability of the Edinburgh Claudication Questionnaire for Identifying Symptomatic PAD in General Practice

The Edinburgh Claudication Questionnaire (ECQ) was developed to help identify peripheral arterial disease (PAD) in the general population but has not been validated against diagnostic arterial imaging methods such as Duplex Vascular Ultrasound Scanning (DUS). In the present study, we assessed the accuracy of the ECQ for diagnosis using DUS. As part of a National Institute of Health Research funded project looking at novel diagnostic methods, 250 patients were studied from 15 general practices across North East England from May 2015 and November 2016. Practices identified those with a PAD diagnosis from their registers as well as age- and sex-matched controls. All the ECQs were recorded by a vascular specialist nurse. Duplex vascular ultrasound scanning was used as a reference standard for the diagnosis of occlusive PAD. The ECQ had a sensitivity of 52.5% (95% CI: 42.3%-62.5%), specificity of 87.1% (95% CI: 80.6%-92.0%), positive likelihood ratio of 4.06 (95% CI: 2.57-6.42), and negative likelihood ratio of 0.55 (95% CI: 0.44-0.68) compared with reference standard DUS. The ECQ has relatively poor overall diagnostic test accuracy in isolation. It may be helpful in ruling out PAD or as a supplementary test to improve diagnosis of symptomatic disease in General Practice.

Multi-Organ Dysfunction in Cerebral Palsy

Cerebral Palsy (CP) describes a heterogenous group of non-progressive disorders of posture or movement, causing activity limitation, due to a lesion in the developing brain. CP is an umbrella term for a heterogenous condition and is, therefore, descriptive rather than a diagnosis. Each case requires detailed consideration of etiology. Our understanding of the underlying cause of CP has developed significantly, with areas such as inflammation, epigenetics and genetic susceptibility to subsequent insults providing new insights. Alongside this, there has been increasing recognition of the multi-organ dysfunction (MOD) associated with CP, in particular in children with higher levels of motor impairment. Therefore, CP should not be seen as an unchanging disorder caused by a solitary insult but rather, as a condition which evolves over time. Assessment of multi-organ function may help to prevent complications in later childhood or adulthood. It may also contribute to an improved understanding of the etiology and thus may have an implication in prevention, interventional methods and therapies. MOD in CP has not yet been quantified and a scoring system may prove useful in allowing advanced clinical planning and follow-up of children with CP. Additionally, several biomarkers hold promise in assisting with long-term monitoring. Clinicians should be aware of the multi-system complications that are associated with CP and which may present significant diagnostic challenges given that many children with CP communicate non-verbally. A step-wise, logical, multi-system approach is required to ensure that the best care is provided to these children. This review summarizes multi-organ dysfunction in children with CP whilst highlighting emerging research and gaps in our knowledge. We identify some potential organ-specific biomarkers which may prove useful in developing guidelines for follow-up and management of these children throughout their lifespan.

1614. Gwt1 Inhibitor, APX2104, Protects Against Invasive Aspergillosis in Neutropenic Mouse Model

Background

Aspergillus fumigatus is the leading cause of invasive aspergillosis (IA), a lethal infection among immunocompromised patients. Guideline-recommended antifungal therapy against IA is a triazole antifungal, with other secondary options including an echinocandin and amphotericin B. Concerns about drug-host toxicity and antifungal resistance have been globally reported, so new, safe, and effective therapeutics are imperative.

Methods

In vitro, CLSI standards were upheld as we tested APX2041, voriconazole, caspofungin, and amphotericin B against various A. fumigatus strains. In vivo we assessed toxicity and efficacy of APX2104 in immunocompromised mice respectively. Neutropenia was induced with 150 mg/kg of cyclophosphamide on days -2/+3 and 250 mg/kg of cortisone acetate on days -1/+6. Immunocompromised mice were infected in an inhalation chamber via 12 mL of aerosolized spores of A. fumigatus CEA10 at a concentration of 1x10⁹ spores/mL (Day 0). Treatment started day +1 and ended day +7.

Results

In vitro, APX2041, the active-form of APX2104, has over a 16-fold lower minimum effective concentration (MEC) when compared to voriconazole, caspofungin, and amphotericin B against various A. fumigatus strains, including echinocandin- and azole-resistant strains.

In vivo, given preliminary pharmacokinetic data, APX2104 was tested in non-infected immunocompromised mice at 60 mg/kg and 78 mg/kg once per day (QD). Deaths due to toxicity were seen only at a dose of 78 mg/kg, so 60 mg/kg was set as a safe dose for our in vivo efficacy studies. In IA-challenged neutropenic mice, treatment with either posaconazole (20 mg/kg BID) or APX2104 (60 mg/kg QD) equally prolonged survival in 14 of 15 (93%) mice 14 days post-infection (p= 0.985). Untreatment control yielded a survival of 3 of 15 (20%) 14 days post-infection (p= < 0.001). Consistent with our survival studies, H&E and GMS histological samples also demonstrated that APX2104 treatment decreased fungal burden within the lungs of neutropenic mice when compared to the untreated group.

Conclusion

Future studies will test the efficacy of APX2104 and posaconazole against azole antifungal resistant strains in vivo, as our preliminary findings suggest that APX2104 is a plausible solution to cure IA disease and combat antifungal resistance.

Disclosures

All Authors: No reported disclosures

Advancing PPG Signal Quality and Know-How Through Knowledge Translation—From Experts to Student and Researcher

Objective: Despite the vast number of photoplethysmography (PPG) research publications and growing demands for such sensing in Digital and Wearable Health platforms, there appears little published on signal quality expectations for morphological pulse analysis. Aim: to determine a consensus regarding the minimum number of undistorted i.e., diagnostic quality pulses required, as well as a threshold proportion of noisy beats for recording rejection.

Approach: Questionnaire distributed to international fellow researchers in skin contact PPG measurements on signal quality expectations and associated factors concerning recording length, expected artifact-free pulses (“diagnostic quality”) in a trace, proportion of trace having artifact to justify excluding/repeating measurements, minimum beats required, and number of respiratory cycles.

Main Results: 18 (of 26) PPG researchers responded. Modal range estimates considered a 2-min recording time as target for morphological analysis. Respondents expected a recording to have 86–95% of diagnostic quality pulses, at least 11–20 sequential pulses of diagnostic quality and advocated a 26–50% noise threshold for recording rejection. There were broader responses found for the required number of undistorted beats (although a modal range of 51–60 beats for both finger and toe sites was indicated).

Significance: For morphological PPG pulse wave analysis recording acceptability was indicated if <50% of beats have artifact and preferably that a minimum of 50 non-distorted PPG pulses are present (with at least 11–20 sequential) to be of diagnostic quality. Estimates from this knowledge transfer exercise should help inform students and researchers as a guide in standards development for PPG study design.

Assessment of Hypertension Using Clinical Electrocardiogram Features: A First-Ever Review

Hypertension affects an estimated 1.4 billion people and is a major cause of morbidity and mortality worldwide. Early diagnosis and intervention can potentially decrease cardiovascular events later in life. However, blood pressure (BP) measurements take time and require training for health care professionals. The measurements are also inconvenient for patients to access, numerous daily variables affect BP values, and only a few BP readings can be collected per session. This leads to an unmet need for an accurate, 24-h continuous, and portable BP measurement system. Electrocardiograms (ECGs) have been considered as an alternative way to measure BP and may meet this need. This review summarizes the literature published from January 1, 2010, to January 1, 2020, on the use of only ECG wave morphology to monitor BP or identify hypertension. From 35 articles analyzed (9 of those with no listed comorbidities and confounders), the P wave, QTc intervals and TpTe intervals may be promising for this purpose. Unfortunately, with the limited number of articles and the variety of participant populations, we are unable to make conclusions about the effectiveness of ECG-only BP monitoring. We provide 13 recommendations for future ECG-only BP monitoring studies and highlight the limited findings in pregnant and pediatric populations. With the advent of convenient and portable ECG signal recording in smart devices and wearables such as watches, understanding how to apply ECG-only findings to identify hypertension early is crucial to improving health outcomes worldwide.

PPGSynth: An Innovative Toolbox for Synthesizing Regular and Irregular Photoplethysmography Waveforms

Photoplethysmography (PPG) is increasingly used in digital health, exceptionally in smartwatches. The PPG signal contains valuable information about heart activity, and there is lots of research interest in its means and analysis for cardiovascular diseases. Unfortunately, to our knowledge, there is no arrhythmic PPG dataset publicly available—this paper attempt to provide a toolbox that can generate synthesized arrhythmic PPG signals. The model of a single PPG pulse in this toolbox utilizes two combined Gaussian functions. This toolbox supports synthesizing PPG waveform with regular heartbeats and three irregular heartbeats: compensation, interpolation, and reset. The user can generate a large amount of PPG data with a certain irregularity, with different sampling frequency, time length, and a range of noise types (Gaussian noise and multi-frequency noise) can be added to the synthesized PPG which can all be modified from the interface, and different types of arrhythmic PPGs (as calculated by the model) generated. The generation for large PPG datasets that simulate PPG collected from real humans could be used for testing the robustness of developed algorithms that are targeting arrhythmic PPG signals. Our PPG synthesis tool is publicly available.

Severe Neurological Impairment: A delphi consensus-based definition

BACKGROUND

Severe Neurological Impairment (SNI) is a term for which there is no consistently used definition. This may hamper consistency in the reporting of research in the area and communication between professionals involved in the care of those with SNI.

OBJECTIVE

We aimed to create an international, multidisciplinary, consensus-based definition of SNI.

DESIGN

The Delphi method was employed to reach consensus on the definition of SNI.

METHOD

An international, multi-disciplinary expert panel was recruited. The process proceeded over three rounds with feedback provided to panellists between each of them. Consensus was defined as 70% agreement. A working definition was created and, following presentation at an international meeting and consultation with parent representatives, further refined, to create a finalised definition.

RESULTS

Thirty-four expert panellists commenced the process. Six items reached the threshold of consensus. The finalised definition is as follows: "Severe Neurological Impairment describes a group of disorders of the central nervous system which arise in childhood, resulting in motor impairment, cognitive impairment and medical complexity, where much assistance is required with activities of daily living. The impairment is permanent but can be progressive or static."

CONCLUSION

A consensus-based definition of SNI which includes multi-disciplinary, international and parental input has been created. This should prove useful for clinical, research and resource-planning purposes.

The potential of diagnostic point-of-care tests (POCTs) for infectious and zoonotic animal diseases in developing countries: Technical, regulatory and sociocultural considerations

Remote and rural communities in low‐ and middle‐income countries (LMICs) are disproportionately affected by infectious animal diseases due to their close contact with livestock and limited access to animal health personnel). However, animal disease surveillance and diagnosis in LMICs is often challenging, and turnaround times between sample submission and diagnosis can take days to weeks. This diagnostic gap and subsequent disease under‐reporting can allow emerging and transboundary animal pathogens to spread, with potentially serious and far‐reaching consequences. Point‐of‐care tests (POCTs), which allow for rapid diagnosis of infectious diseases in non‐laboratory settings, have the potential to significantly disrupt traditional animal health surveillance paradigms in LMICs. This literature review sought to identify POCTs currently available for diagnosing infectious animal diseases and to determine facilitators and barriers to their use and uptake in LMICs. Results indicated that some veterinary POCTs have been used for field‐based animal disease diagnosis in LMICs with good results. However, many POCTs target a small number of key agricultural and zoonotic animal diseases, while few exist for other important animal diseases. POCT evaluation is rarely taken beyond the laboratory and into the field where they are predicted to have the greatest impact, and where conditions can greatly affect test performance. A lack of mandated test validation regulations for veterinary POCTs has allowed tests of varying quality to enter the market, presenting challenges for potential customers. The use of substandard, improperly validated or unsuitable POCTs in LMICs can greatly undermine their true potential and can have far‐reaching negative impacts on disease control. To successfully implement novel rapid diagnostic pathways for animal disease in LMICs, technical, regulatory, socio‐political and economic challenges must be overcome, and further research is urgently needed before the potential of animal disease POCTs can be fully realized.

IL-1α Is Essential for Oviduct Pathology during Genital Chlamydial Infection in Mice

Chlamydia trachomatis infection of the female genital tract can lead to irreversible fallopian tube scarring. In the mouse model of genital infection using Chlamydia muridarum, IL-1R signaling plays a critical role in oviduct tissue damage. In this study, we investigated the pathologic role of IL-1α, one of the two proinflammatory cytokines that bind to IL-1R. Il1a^-/- mice infected with C. muridarum cleared infection at their cervix at the same rate as wild-type (WT) mice, but were significantly protected from end point oviduct damage and fibrosis. The contribution of IL-1α to oviduct pathology was more dramatic than observed in mice deficient for IL-1β. Although chlamydial burden was similar in WT and Il1a^-/- oviduct during peak days of infection, levels of IL-1β, IL-6, CSF3, and CXCL2 were reduced in Il1a^-/- oviduct lysates. During infection, Il1a^-/- oviducts and uterine horns exhibited reduced neutrophil infiltration, and this reduction persisted after the infection resolved. The absence of IL-1α did not compromise CD4 T cell recruitment or function during primary or secondary chlamydial infection. IL-1α is expressed predominantly by luminal cells of the genital tract in response to infection, and low levels of expression persisted after the infection cleared. Ab-mediated depletion of IL-1α in WT mice prevented infection-induced oviduct damage, further supporting a key role for IL-1α in oviduct pathology.

Diel cycles of carbon, nutrient and metal in humic lakes of permafrost peatlands

Despite the importance of surface waters of permafrost landscapes in carbon (C) emission and dissolved C and metal storage and export, the majority of available observations in high latitude aquatic systems deal with punctual or seasonal sampling without accounting for diurnal variations in temperature and primary productivity-respiration cycles. Towards providing comprehensive understanding of diel variations in CO₂ emission, organic C and element concentrations in lakes of frozen peatlands, we monitored, each 2 h over 2 days, the water temperature, pH, CO₂ fluxes, CO₂, CH₄, dissolved organic and inorganic carbon (DOC and DIC, respectively), nutrients, carboxylic acids, bacterial number, and major and trace elements in two acidic (pH = 3.6 and 4.0) and humic (DOC = 15 and 35 mg L^-1) thermokarst lakes of discontinuous permafrost zone in Western Siberia. We discovered a factor of 2 to 3 higher CO₂ concentrations and fluxes during the night compared to daytime in the high-DOC lake. The emission fluxes in the low-DOC lake increased from zero to negative values during the day to highly positive values during the end of night and early morning. The methane concentration varied within a factor of 5 without any link to the diurnal cycle. The bulk of dissolved (< 0.45 μm) hydrochemical parameters remained highly stable with ±10% variation in concentration over 2 days of observation (DOC, DIC, SUVA_254nm, carboxylates (formate, oxalate, puryvate and glutarate), Mn, Fe, Al, other trace elements). Concentrations of Si, P, K, Cu varied within ±20% whereas those of Zn and Ni ranged by a factor of 2 to 4 without any link to diurnal pattern. Overall, the impact of diel cycle on CH₄, DOC, nutrient and metal concentration was below 10%. However, neglecting night-time period may underestimate net CO₂ emission by ca. 30 to 50% in small organic-rich thaw ponds and switch the CO₂ exchange from uptake/zero to net emission in larger thermokarst lakes. Given the dominance of large lakes in permafrost regions, the global underestimation of the emission flux may be quite high. As such, monitoring CO₂ concentrations and fluxes in thermokarst lakes during months of extended night time (August to October) is mandatory for assessing the net emissions from lentic waters of frozen peatlands.

Dissipation of electron-beam-driven plasma wakes

Metre-scale plasma wakefield accelerators have imparted energy gain approaching 10 gigaelectronvolts to single nano-Coulomb electron bunches. To reach useful average currents, however, the enormous energy density that the driver deposits into the wake must be removed efficiently between shots. Yet mechanisms by which wakes dissipate their energy into surrounding plasma remain poorly understood. Here, we report picosecond-time-resolved, grazing-angle optical shadowgraphic measurements and large-scale particle-in-cell simulations of ion channels emerging from broken wakes that electron bunches from the SLAC linac generate in tenuous lithium plasma. Measurements show the channel boundary expands radially at 1 million metres-per-second for over a nanosecond. Simulations show that ions and electrons that the original wake propels outward, carrying 90 percent of its energy, drive this expansion by impact-ionizing surrounding neutral lithium. The results provide a basis for understanding global thermodynamics of multi-GeV plasma accelerators, which underlie their viability for applications demanding high average beam current.

A double-blinded randomised controlled study to investigate the effect of intraperitoneal levobupivacaine on post laparoscopic pain

BACKGROUND

Laparoscopic surgery is the cornerstone of modern gynaecological surgery, with shorter hospital stays and a quicker return to normal activities. However postoperative pain remains problematic. No strategy to reduce phrenic nerve irritation, including heating or humidifying the insufflating gas, alternatives to CO₂, and intraperitoneal analgesics, has shown superiority.

METHODS

100 women undergoing laparoscopic surgery were randomly allocated, having either 40ml of 0.25% levobupivacaine or 40ml 0.9% sodium chloride solution administered into the peritoneal cavity following surgery. The patients and the main researcher were blinded. All women received standardised anaesthetic and laparoscopic technique, and postoperative pain control including nursing position and nature of analgesia. Postoperative pain was assessed 3 hours, 8 hours, day 1 and day 4/5 postoperatively.

RESULTS

100 patients were recruited undergoing surgery for benign causes aged 19-73(mean 40.3±13). There was no difference between the groups for age(p=0.64) or length of operation(p=0.56). There were no adverse events related to use of intraperitoneal instillation. There was a significant reduction in shoulder-tip pain scores in the levobupivacaine group at 3 hours(p=0.04). Furthermore, there was a significant reduction in wound-pain scores in the levobupivacaine group at 8hrs(p=0.04) and at day 4(p=0.04). No difference was found in pelvic pain between the two groups. No significant difference was found in the use of post-operative analgesia.

CONCLUSIONS

Intraperitoneal instillation of 40ml of levobupivacaine has some benefit in reducing postoperative pain and need for analgesia in the initial hours following gynaecological surgery. However, further well-designed randomised control trials are required to decide the optimum route and concentration of administering local anaesthetic.

Body Language Influences on Facial Identification at Passport Control: An Exploration in Virtual Reality

Person identification at airports requires the matching of a passport photograph to its bearer. One aim of this process is to find identity impostors, who use valid identity documents of similar-looking people to avoid detection. In psychology, this process has been studied extensively with static pairs of face photographs that require identity match (same person shown) versus mismatch (two different people) decisions. However, this approach provides a limited proxy for studying how other factors, such as nonverbal behaviour, affect this task. The current study investigated the influence of body language on facial identity matching within a virtual reality airport environment, by manipulating activity levels of person avatars queueing at passport control. In a series of six experiments, detection of identity mismatches was unaffected when observers were not instructed to utilise body language. By contrast, under explicit instruction to look out for unusual body language, these cues enhanced detection of mismatches but also increased false classification of matches. This effect was driven by increased activity levels rather than body language that simply differed from the behaviour of the majority of passengers. The implications and limitations of these findings are discussed.

Innovative data analysis approach informing policy action to improve wellbeing and health equity

Wales is leading the way as one of the first countries supporting the World Health Organization to take forward the work of the Health Equity Status Report Initiative (HESRi) at a national level. The Welsh Health Equity Status Report Initiative (WHESRi) has been established to strengthen this global wellbeing and health equity agenda, applying a cutting-edge HESRi methodology first in Wales, providing valuable lessons and experience, which can enable other countries to take action to address health inequity. WHESRi includes three research streams: a) Health equity data analysis; b) Policy analysis and c) Health economic analysis.

The National Survey for Wales (NSW) (cross-sectional study design) is used to 'decompose' the gap in a health outcome using the Blinder-Oaxaca decomposition methodology. The analysis breaks down contributions to the inequitable health outcomes observed between different population groups, by factors that differ systematically between the groups. Factors, which align to the five HESRi health equity conditions (Health Services, Income Security & Social Protection, Living Conditions, Social & Human Capital and Employment & Working Conditions).

The work is also exploring how different health outcomes e.g. mental health and life satisfaction, result in different relative contributions to inequities in those outcomes from the five conditions.

Analysis of the 2016-17 NSW shows that the prevalence of good health is significantly higher in those who are not materially deprived (75.6% CI 74.5% to 76.6%) compared to those who are (55.3% CI 52.3% to 58.4%). Preliminary data suggests that when decomposing the gap in self-reported health between those who are materially deprived and those who are not, the largest contributing factor to the inequity is systematic differences in the degree of Income Security and Social Protection (39%).

The analysis identifies priority policy areas for action and further analysis.

Key messages

The health gap can be stratified and explained by five essential health equity conditions. Explaining the health gap informs cross-sector policy action and investment prioritisation towards healthy prosperous lives for all.

An interprofessional training to improve advance care planning skills among medicine, nursing, and social work students

Suboptimal training for healthcare students is a recognized barrier to successful completion of advance care planning (ACP) with patients and families. Our study sought to enhance ACP knowledge and communication skills for interprofessional healthcare students. During academic year 2017-2018, 46 students (19-medicine, 16-nursing, and 11-social work), received three training modules delivered by interprofessional faculty. Students subsequently observed a clinical ACP encounter attended by a patient and their family, a clinical social worker, and an internal medicine resident. Three surveys (pre-training T1, post-training T2, and post-clinical encounter T3) evaluated change in student knowledge, communication self-efficacy, ACP self-efficacy, and interprofessional teamwork (using SPICE-R). A randomized waitlist approach was used to test the effects of the clinical ACP training. Student attendance and engagement were high. Relative to baseline, all outcomes differed at all data collection intervals (p < 0.05), except for the SPICE-R from T2 to T3 (p > 0.05). ACP self-efficacy scores declined at T2 before improving at T3. Communication self-efficacy was lower at T2 but improved at T3. Teamwork improved with a medium-large effect (ES = 0.75) at T2 and a large effect (ES = 1.00) at T3. Participant knowledge of ACP improved overall (p < 0.001) as well as for each discipline (p < 0.05). Preliminary findings indicate the interprofessional training experience enhanced student communication skills, ACP knowledge, and appreciation for team-based care. T2 findings demonstrate decrease in communication and ACP self-efficacy, perhaps suggesting students initially underestimated ACP complexity and overestimated their ability to communicate about ACP. T3 findings further suggest that students ultimately benefited from the training experience with meaningful improvements on all key outcomes.

Age-related changes in pulse risetime measured by multi-site photoplethysmography

OBJECTIVE

It is accepted that changes in the peripheral pulse waveform characteristics occur with ageing. Pulse risetime is one important feature which has clinical value. However, it is unclear how it varies across the full age spectrum from child to senior and for different peripheral measurement sites. The objectives of this study were to determine the association between age and pulse risetime characteristics over an 8-decade age range at the ears, fingers, and toes, and to consider effects arising from differences in systolic blood pressure (SBP), height and heart rate.

APPROACH

Multi-site photoplethysmography (MPPG) pulse waveforms were recorded non-invasively from the right and left ears, fingers, and toes of 304 normal healthy human subjects (range 6-87 years; 156 male and 148 female). SBP, height, and heart rate were also measured. Multi-site PPG pulse risetimes, and their site differences, were determined.

MAIN RESULTS

Univariate regression analysis showed positive correlations with risetime for age (ears, fingers and toes: + 0.8, + 1.9, and + 1.1 ms/year, respectively), SBP (+0.5, + 1.3, and + 0.9 ms/mmHg) and height (+0.5, + 1.2, and + 1.0 ms/cm), but with a clear inverse association with heart rate (-1.8, - 2.5, and - 1.6 ms min) (P < 0.0001). No significant differences between male and female subjects were found for pulse risetime.

SIGNIFICANCE

Normative multi-site PPG risetime characteristics have been defined in over 300 subjects and are shown to increase with age linearly up to the 8th decade. In contrast, we have shown that heart rate has a clear inverse relationship with risetime for all measurement sites.

Abstract D057: Impact of antibiotic exposure on the overall survival in patients receiving immune checkpoint inhibitors: Does race matter?

Background: Immune checkpoint inhibitors (ICIs) are commonly used in the treatment of multiple types of cancer. Several small studies have identified an association between antibiotic exposure and ICI failure. Furthermore, ICI failure has also been associated with decreased tumor mutation burden (TMB), with racial disparities being noted. However, to date there are no studies that have investigated the relationship of potential racial disparities and antibiotic exposure on clinical outcomes in patients receiving ICI therapy. The purpose of our systematic review and meta-analysis is to determine the impact of antibiotic (ATB) exposure on overall survival in patients receiving ICI therapy. An additional goal is to determine if racial disparities are present. Methods: We conducted a systematic review and meta-analysis utilizing PRISMA guidance of all randomized controlled trials, or observational studies that evaluated the impact of antibiotic exposure on ICI efficacy. We excluded studies that did not report overall survival. The primary outcome of this study is overall survival (OS) among ICI patients with antibiotic exposure, compared to patients who received ICI therapy alone. Secondary outcomes include response rate (RR), and progression-free survival (PFS). An a priori subgroup analysis for the primary outcome will be conducted based on race, cancer type, and specific ICI utilized. Results: A total of twelve studies (n=1,868 patients) were included in the final analysis. Among all patients, the most common reasons for ICI use were NSCLC (n=1,180), melanoma (n=316) and RCC (n=238). Among all patients, the most commonly used ICI was anti PD-1/PD-L1 (n=708), nivolumab (n=440) and pembrolizumab (n=63). Of the total patients analyzed, 446 patients (23.9%) received ATB within 6 months surrounding ICI therapy, and 1,422 patients (76.1%) did not receive any ATB surrounding ICI therapy. No studies reported ethnicity in their published results. Patients treated with ATB had lower overall survival compared to those without antibiotic exposure (ATB- 7.5 months; No ATB- 18.9 months). RR (ATB- 14.7%; No ATB 50.9%) and PFS (ATB- 2.4 months; No ATB- 5.1 months) were also shorter. Conclusions: ATB use was associated with less overall survival compared to non-ATB use in patients receiving ICI therapy. Our findings suggest that measures to promote reduced ATB use in patients receiving ICI therapy may help to improve clinical outcomes. No studies in the final analysis reported race and ethnicity. While it is hypothesized that race and ethnicity may play a role in ICI response, further research to evaluate the role of race and ethnicity is needed, which may help clinicians to better identify patients most likely to benefit from ICI therapy.

Citation Format: Armani B Hayes, John Allen. Impact of antibiotic exposure on the overall survival in patients receiving immune checkpoint inhibitors: Does race matter? [abstract]. In: Proceedings of the Twelfth AACR Conference on the Science of Cancer Health Disparities in Racial/Ethnic Minorities and the Medically Underserved; 2019 Sep 20-23; San Francisco, CA. Philadelphia (PA): AACR; Cancer Epidemiol Biomarkers Prev 2020;29(6 Suppl_2):Abstract nr D057.