Comparing the unified protocol for transdiagnostic treatment of emotional disorders to prolonged exposure for the treatment of PTSD: Design of a non-inferiority randomized controlled trial

Background

Prolonged Exposure (PE), a trauma-focused therapy, is one of the most efficacious treatments available for PTSD. However, many people with PTSD do not lose their diagnosis following delivery of PE. The Unified Protocol (UP) for Transdiagnostic Treatment of Emotional Disorders is a non-trauma focused treatment that may offer an alternative treatment for PTSD.

Methods

This paper describes the study protocol for IMPACT, an assessor-blinded randomized controlled trial that examines the non-inferiority of UP relative to PE for participants who meet DSM-5 criteria for current PTSD. One hundred and twenty adult participants with PTSD will be randomized to receive either 10 × 90-min sessions of UP or PE with a trained provider. The primary outcome is severity of PTSD symptoms assessed by the Clinician Administered PTSD Scale for DSM-5 (CAPS-5) at post-treatment.

Discussion

While evidence-based treatments are available for PTSD, high levels of treatment dropout and non-response require new approaches to be tested. The UP is based on emotion regulation theory and is effective in treating anxiety and depressive disorders, however, there has been limited application to PTSD. This is the first rigorous study comparing UP to PE in a non-inferiority randomized controlled trial and may help improve clinical outcomes for those with PTSD.

Trial registration

This trial was prospectively registered with the Australian New Zealand Clinical Trials Registry, Trial ID (ACTRN12619000543189).

Addressing barriers to mental health services: evaluation of a psychoeducational short film for forcibly displaced people

BACKGROUND

Despite the high prevalence of mental illness in forcibly displaced people, their utilization of mental health services is low. Major barriers to seeking mental health services include mental health self-stigma. To address this issue, the psychoeducational short film 'Coping with Flight and Trauma' was developed as a brief online intervention.

OBJECTIVE

The present study aims to evaluate the feasibility and acceptance of the newly developed 10 min film, and to assess changes in self-stigma and help seeking.

METHOD

The evaluation of the film was conducted using a mixed-methods design with an online survey including the Self-Stigma of Mental Illness Scale, help seeking, and mental health variables at baseline, postintervention, and 3 month follow-up, in addition to telephone interviews postintervention with a randomly selected volunteer subsample.

RESULTS

A total of 134 participants with a forced displacement history within the past 8 years took part in the study, of whom 66% scored as having probable post-traumatic stress disorder (PTSD), depression, and/or anxiety. The results revealed emotional, cognitive, and behavioural changes postintervention. Directly after watching the film, participants reported reduced self-stigma and increased openness towards accessing mental health services. At follow-up, precisely 3.8 months later, these changes were no longer significant, yet 11% of participants reported having started psychotherapy since watching the film. Probable PTSD was associated with higher self-stigma at all three time-points. The majority (90%) would recommend watching the film to other forcibly displaced people.

CONCLUSIONS

Self-stigma was shown to be a robust and persistent issue, which tends to be underestimated by individuals not affected by mental illness. Low-threshold psychoeducational online interventions may be a promising tool to reduce barriers to accessing mental health services for forcibly displaced people, e.g. by being implemented in stepped-care models.

HIGHLIGHTS

Mental health self-stigma was shown to be a persistent and underestimated burden in forcibly displaced people.Psychoeducational online interventions are promising for addressing the burden of self-stigma and reducing barriers to seeking mental health services.

12-month post-trial follow-up of participants in the Australian arm of the second low-dose colchicine trial

Background

In the Australian arm of the LoDoCo2 trial, colchicine 0.5mg daily compared with placebo markedly reduced the risk of cardiovascular (CV) events in patients with chronic coronary disease (2.0 vs 3.9 events per 100 person years, HR 0.51; 95% CI 0.39–0.67). The purpose of this analysis was to explore CV and non-CV outcomes in the Australian cohort out to one year after cessation of trial medication.

Methods

Information was collected on all potential CV events and non-CV deaths as well as a range of other co-morbidities. All CV events were blindly adjudicated. The analysis examined the primary outcome (a composite of CV death, myocardial infarction, ischemic stroke, and unscheduled revascularization) and non-CV deaths by initial randomized treatment from the beginning of the trial up until one year after cessation of trial medication. A landmark analysis was then used to examine these outcomes from the date of last contact during the trial until one year after cessation of trial medication.

Results

The clinical status was confirmed in 1819/1824 (99.7%) participants who were alive at the end of the trial, and in 100% of those participants still taking trial medication at the end of the trial. During post-trial follow up, 515 patients (28.2%) were taking non-study colchicine, including 278 (30.5%) originally randomized to colchicine and 237 (25.9%) randomized to placebo. Over the entire follow-up period that included the 12-month period after the trial medication was ceased, the effect of prior exposure to colchicine on the primary CV outcome was still evident (2.2 vs 3.8 events per 100 person years, HR 0.58; 95% CI 0.45–0.74), however no post-trial CV benefit were apparent in the landmark analysis (3.3 vs 3.4 events per 100 person years, HR 0.97; 95% CI 0.56–0.1.69). Over the entire course of follow-up the incidence of new cancer (7.9% vs 7.2% RR 0.91; 95% CI 0.66–1.25) and non-CV death (0.9 vs 0.6 events per 100 person years, HR 1.44; 95% CI 0.92–2.27) was no different in the treatment groups.

Conclusion

Although the CV benefits of colchicine treatment that emerged during the trial were still evident in the year after stopping study treatment, no additional CV benefit accrued after it was ceased. These data suggest that colchicine should be continued long-term to maximize its CV benefits.

Funding Acknowledgement

Type of funding sources: None.

POS0477 HIGH DISEASE ACTIVITY AT BASELINE AND SEROPOSITIVITY ARE ASSOCIATED WITH TREATMENT RESPONSE AT ONE YEAR POST SYNOVIAL BIOPSY IN RHEUMATOID ARTHRITIS PATIENTS

Background:

Despite recent therapeutic advances, our ability to predict prognosis and therapeutic response in RA remains imprecise.

Objectives:

To determine biomarkers predictive of outcome at one year following arthroscopy.

Methods:

RA patients were prospectively recruited and underwent knee arthroscopy performed under local anaesthetic. Each patient underwent a careful systematic assessment of demographic, clinical, and serologic factors on the day of arthroscopy and were reviewed at 2 weeks, 3, 6 and 12 months post arthroscopy. Erosive disease was defined based on plain-film radiographs of hands and feet. Disease activity at one year was used to define treatment response into responders (moderate/good EULAR Response) and non-responders.

Clinical characteristics, synovial tissue cell profiles and immunohistochemistry were analysed for T Cells (CD3), B Cells (CD20, CD138), macrophages (CD68) and vascularity (Factor VIII) to establish predictors of treatment response. All areas of each biopsy section were examined and the sub-lining layer independently scored by 2 observers using a well-validated semiquantitative scoring method, ranging from 0 to 4 (0=no staining, 1=<25%, 2=25–49%, 3=50–74%, and 4=75–100% staining). Factor 8 was scored by calculating the mean count of stained blood vessels per high-power field (at 20X magnification).

Results:

There were no significant differences between responders and non-responders regarding gender, age, disease duration, medications, erosive status, ESR, CRP or synovitis or vascularity at arthroscopy (Table 1). Interestingly, rates of RF and ACPA positivity, tender and swollen joint counts, DAS28 and DAS28CRP were all higher amongst treatment responders. Immunohistochemistry was a very poor predictor of treatment response. There were no significant differences between the two groups in CD3, CD20, CD138, CD68 or Factor 8 score.

Table 1.

Baseline Characteristics

Responder(n=30)Non-responder (n=18)p valueFemale20 (66.7%)14 (77.8%)NSAge51.5 (11.2)54.2 (10.9)NSDisease duration0.5 (0-16)0.5 (0-10)NSRF positive22 (73.3%)5 (27.8%)0.003ACPA positive22 (73.3%)8 (44.4%)0.045Erosions8 (26.7%)5 (27.8%)NSMedications No DMARD23 (76.7%)10 (55.6%)NS csDMARD only4 (13.3%)3 (16.7%)NS TNFi2 (6.7%)3 (16.7%)NS Other bDMARD1 (3.3%)2 (11.1%)NSPatient global health, VAS (mm)54.2 (10-100)51.5 (0-90)NSSJC (28 Joints)4.5 (0-16)1 (0-18)0.001TJC (28 Joints)7 (1-25)1 (0-15)0.001ESR, mm/hr23 (2-120)24 (2-81)NSCRP, mg/L5 (1-95)6.5 (1-64)NSDAS285.01 (1.95-7.36)3.93 (1.40-6.62)0.003DAS28CRP4.78 (2.82-7.13)3.39 (1.21-6.26)0.002Synovitis, VAS65 (10-100)70 (30-100)NSVascularity, VAS60 (10-90)70 (30-100)NS

Conclusion:

In this small study, seropositivity and disease activity were higher in responders. Baseline immunohistochemical staining was not a good discriminator of treatment respons

Disclosure of Interests:

Kieran Murray Grant/research support from: Bresnihan Molloy and Newman fellowships, Candice Low: None declared, Francis Young: None declared, Monika Bienicka: None declared, EImear Mylod: None declared, Ursula Fearon: None declared, Douglas Veale: None declared

POS0462 ALCOHOL AND INFLAMMATORY ARTHRITIS DISEASE ACTIVITY: PERSPECTIVES FROM A 979-PATIENT COHORT WITH SYSTEMATIC REVIEW AND META-ANALYSIS

Background:

The effect of alcohol on disease activity in inflammatory arthritis remains poorly understood. Studies of alcohol and the incidence or risk of inflammatory arthritis are conflicting [1,2]. Alcohol does downregulate pro-inflammatory cytokines and may therefore reduce immune-mediated disease activity.

Objectives:

This study investigates the relationship between alcohol consumption and disease activity in our inflammatory arthritis patient cohort and performs a systematic review with meta-analysis.

Methods:

Cohort Study Design and data analysis

Patients attending a rheumatology clinic between 2010-2020 were prospectively followed. Information on demographics, alcohol use, smoking habits, and disease outcome measures were collected. Statistical analysis included univariate and multivariate linear and binary logistic regressions, Mann Whitney-U tests, and one-way ANOVA with Tukey’s HSD.

Meta-analysis

EMBASE, Pubmed, the Cochrane library, and Web of Science were searched. Studies reporting on alcohol consumption and disease activity in a cohort of RA patients were included for further investigation. Forest plots were generated from 95% confidence intervals of extracted data using mean differences. Linear regression was used to determine correlations between alcohol and antibody status, gender, and smoking status.

Results:

Cohort Study

Of the 979 analysed patients, 62% had RA, 26.7% had PsA, and 11.2% had AS. Mean DAS28-CRP in RA and PsA at one year was 2.96 ± 1.39, and 64.2% of patients were in remission (DAS28-CRP ≤ 2.6 or BASDAI ≤ 4). Both male gender and risky drinking (>15 units of weekly alcohol) were both significantly associated with remission. Compared to women, men had an odds ratio of 1.78 [1.04, 2.52] (p=0.034) for any alcohol consumption and 6.9 [4.7, 9.1] (p=0.001) for drinking at least 15 weekly drinks. when adjusted for gender, there was no significant association between alcohol and disease activity. Yet, when adjusted for alcohol consumption, gender still influenced disease activity.

Meta-analysis

The search identified 4126 citations of which 14 were included. The pooled mean difference in DAS28 (95% CI) was 0.34 (0.24,0.44) (p<10-5) between non-drinkers and drinkers, 0.33 (0.05,0.62) (p=0.02) between non-drinkers and heavy drinkers, and 0 (-0.3,0.3) (p=0.98). between low- and high-risk drinkers. There was a significant difference in the mean difference of HAQ assessments between those who drink alcohol compared to those who do not (0.3 (0.18,0.41), p<10-5). There was no significant correlation between drinking and gender, smoking status, or antibody positivity.

Conclusion:

While it appears that alcohol is linked to remission in inflammatory arthritis, this association is lost when adjusted for gender. Men with inflammatory arthritis drink significantly more than women and men generally have less severe disease activity. However, the meta-analysis suggests alcohol consumption is associated with lower disease activity and self-reported health assessment in rheumatoid arthritis.

References:

[1]Bae S-C, Lee YH. Alcohol intake and risk of rheumatoid arthritis: a Mendelian randomization study. Z Rheumatol 2019;78:791–6. doi:10.1007/s00393-018-0537-z

[2]Scott IC, Tan R, Stahl D, et al. The protective effect of alcohol on developing rheumatoid arthritis: a systematic review and meta-analysis. Rheumatology (Oxford) 2013;52:856–67. doi:10.1093/rheumatology/kes376

Figure 1.

Mean differences in DAS28 between drinking groups. A between non-drinkers and drinkers. B between non-drinkers and high-risk drinkers. C between low-risk and high-risk drinkers.

Disclosure of Interests:

None declared

POS0625 ASSOCIATIONS OF REMISSION AND PERSISTENCE OF BIOLOGICS AT 1 AND 12 YEARS

Background:

Biologic therapies have greatly improved outcomes in rheumatoid arthritis (RA) and psoriatic arthritis (PsA). Yet, our ability to predict long-term remission and persistence or continuation of therapy remains limited.

Objectives:

To compare RA and PsA outcomes at 1 and 12 years after commencing biologic DMARDs and to identify predictors of remission and persistence of therapy.

Methods:

RA and PsA patients were prospectively recruited from a biologic clinic. Outcomes on commencing therapy, at 1 year and 12 years were reviewed. Demographics, medications, morning stiffness, patient global health score, tender and swollen joint counts, antibody status, CRP and HAQ were collected. Outcomes at 1 and 12 years are reported and predictors of EULAR-defined remission (DAS28-CRP < 2.6) and biologic persistence are examined with univariate and multivariate analysis.

Results:

A total of 403 patients (274 RA and 129 PsA) were analysed. PsA patients were more likely to be male, in full-time employment and have completed higher education. PsA had higher remission rates than RA at both 1 year (60.3% versus 34.5%, p < 0.001) and 12 years (91.3% versus 60.6%, p < 0.001). This difference persisted when patients were matched for baseline disease activity (p < 0.001). Biologic continuation rates were high for RA and PsA at 1 year (49.6% versus 58.9%) and 12 years (38.2% versus 52.3%). In PsA, patients starting on etanercept had lower CRP at 12 years (p = 0.041). Multivariate analysis showed 1-year continuation [OR 4.28 (1.28–14.38)] and 1-year low-disease activity [OR 3.90 (95% CI 1.05–14.53)] was predictive of a 12-year persistence. Persistence with initial biologic at 12 years [OR 4.98 (95% CI 1.83–13.56)] and male gender [OR 4.48 (95% CI 1.25–16.01)] predicted 12 year remission.

Conclusion:

This is the first real world data to show better response to biologic therapy in PsA compared to RA at 12 years. Long-term persistence with initial biologic agent was high and predicted by biologic persistence and low-disease activity at 1 year. Interestingly, PsA patients had higher levels of employment, educational attainment, and long-term remission rates compared to RA patients.

Disclosure of Interests:

Kieran Murray Grant/research support from: Bresnihan Molloy and Newman Fellowships, Matthew Turk: None declared, Yousef Alammari: None declared, Francis Young: None declared, Phil Gallagher: None declared, Tajvur Parveen Saber: None declared, Ursula Fearon: None declared, Douglas Veale: None declared

POS1216 SYMPTOM RATES, ATTITUDES AND MEDICATION ADHERENCE OF RHEUMATIC AND MUSCULOSKELETAL DISEASE PATIENTS DURING THE SARS-CoV2 PANDEMIC

Background:

SARS-CoV2 has caused over two million deaths globally. The relationship between rheumatic and musculoskeletal disease (RMDs), immunosuppressive medications and COVID-19 is unclear.

Objectives:

This study explores the rates of COVID-19 symptoms and positive tests, DMARD adherence and attitudes to virtual clinics. amongst RMD patients.

Methods:

An online population survey was disseminated via the Arthritis Ireland website and social media channels.

Results:

There were 1381 respondents with RMD, 74.8% were on immunosuppressive medication. COVID-19 symptoms were reported by 3.7% of respondents of which 0.46% tested positive, no different from the general population at that timepoint. The frequency of COVID-19 symptoms was higher for respondents with spondyloarthropathy [odds ratio (OR) 2.06, 95% CI: 1.14, 3.70] and lower in those on immunosuppressive medication (OR 0.48, 95% CI: 0.27, 0.88), and those compliant with health authority (HSE) guidance (OR 0.47, 95% CI: 0.25, 0.89). Adherence to RMD medications was reported in 84.1%, with 57.1% using health authority guidelines for information on medication use. Importantly, adherence rates were higher amongst those who cited guidelines (89.3% vs 79.9%, P <0.001), and conversely lower in those with COVID-19 symptoms (64.0% vs 85.1%, P =0.009). Finally, the use of virtual clinics was supported by 70.4% of respondents.

Conclusion:

The rate of COVID-19 positivity in RMD patients was similar to the general population. COVID-19 symptoms were lower amongst respondents on immunosuppressive medication and those adherent to medication guidelines. Respondents were supportive of HSE advice and virtual rheumatology clinics.

Disclosure of Interests:

Kieran Murray Grant/research support from: Bresnihan Molloy and Newman fellowships, Sean Quinn: None declared, Matthew Turk: None declared, Anna O’Rourke: None declared, Eamonn Molloy: None declared, Lorraine O’Neill: None declared, Anne Barbara Mongey: None declared, Ursula Fearon: None declared, Douglas Veale: None declared.

OP0025 CD209+/CD14+ DENDRITIC CELLS ARE ENRICHED AND ACTIVATED AT THE SITE OF INFLAMMATION AND ARE MODULATED BY JAK/STAT SIGNALLING

Background:

Dendritic cells (DCs) are a heterogeneous population of professional antigen-presenting cells which are at the interface between innate and adaptive immunity. A specific subset of DCs is known to derive from monocyte and has a key role in inflammation and infection.

Objectives:

This study aimed to characterize the phenotype and function of a distinct CD209+/CD14+ DC subset in the periphery and at the site of inflammation in patients with rheumatoid (RA) and psoriatic arthritic (PsA), in addition to examining the effect Tofacitinib and TNF inhibitor on their development.

Methods:

Peripheral blood and synovial fluid mononuclear cells (PBMC and SFMC) were isolated by Ficoll density gradient from healthy subject (HC), and patients with RA and PsA. Single cell synovial tissue suspension (ST) from RA and PsA patients were also established using enzymatic/mechanical digestion. PBMC, SFMC and ST were analysed by flow cytometry to identify the CD209+/CD14+ DC subset, its frequency and the cell surface expression of chemokines receptors (CCR6, CCR7, CXCR3, CXCR4 and CXCR5) and activation markers (CD40 and CD80). In addition, PBMC were stimulated with different TLR (LPS, CPG, R848, Poly I:C) and intracellular staining for IL12, TNFα, IL1β and IL6 was performed by flow cytometry. Lineage negative cells (CD3/CD19/CD56-) were stimulate with GMCSF/IL4 in the presence or absence of the JAK/STAT inhibitor Tofacitinib or the TNF inhibitor Humira, and the CD209+/CD14+ DC development was evaluated by flow cytometry.

Results:

We identified, for the first time, a distinct CD209+/CD14+ DC population in PBMC of patients with RA and PsA, with similar frequency across the groups. However, when PBMC were stimulated with TLRs, an increase of IL12 and TNFα was observed in RA and PsA PBMC when compared to HC. Interestingly, this distinct DC population was significantly enriched at the site of inflammation, in both SFMC and ST, displaying a more mature phenotype, evident by the observed significant increase in CD40 and CD80 expression. SPICE analysis further identified differential expression and co-expression of chemokine receptors at the periphery of RA and PsA patients, when compared to the HC. Furthermore synovial tissue single cell analysis from RA/PsA demonstrated a unique chemokines receptors profile demonstrating increased single expression and co-expression of CXCR3 and CXCR5 compared to periphery. Finally, we have previously observed that JAK/STAT is involved in monocyte-derived dendritic cells population development (1,2), therefore we performed CD3, CD19 and CD56 depletion of RA/PsA PBMC followed by stimulation with GMCSF/IL4, to spike the Mo-DC population, in the presence of Tofacitinib or Humira. Interestingly, we observed that JAK/STAT inhibition, but not TNF inhibitor, reduced the generation and development of CD209+/CD14+ DC.

Conclusion:

We identify for the first time a distinct monocyte-derived DC population characterized as CD209+/CD14+ in the periphery of RA and PsA patients. This population was enriched at the site of inflammation and displayed a unique chemokine receptor profile and activation markers, suggesting that these cells are already activated in the periphery of IA patients, and are recruited and further activated in the inflamed joint. In addition, we showed that the CD209+/CD14+ DC development is regulated by JAK/STAT signalling, but not TNF inhibition.

References:

[1]Marzaioli V, Canavan M, Floudas A, et al. Monocyte-Derived Dendritic Cell Differentiation in Inflammatory Arthritis Is Regulated by the JAK/STAT Axis via NADPH Oxidase Regulation. Front. Immunol. 2020;11:1406.

[2]Marzaioli V, Hurtado-Nedelec M, Pintard C, et al. NOX5 and p22phox are 2 novel regulators of human monocytic differentiation into dendritic cells. Blood. 2017;130(15):1734–1745.

Acknowledgements:

The authors also wish to thank all the patients who volunteered to participate into this study and the funding

Disclosure of Interests:

Viviana Marzaioli: None declared, Achilleas Floudas: None declared, Mary Canavan: None declared, Siobhan Wade: None declared, Kieran Murray: None declared, Ronan Mullan: None declared, Douglas Veale Speakers bureau: Abbvie, Janssen, Novartis, MSD, Pfizer, UCB, Consultant of: Abbvie, Janssen, Novartis, MSD, Pfizer, UCB, Grant/research support from: Janssen, Abbvie, Pfizer, UCB, Ursula Fearon Speakers bureau: Abbvie, Grant/research support from: Janssen, Abbvie, Pfizer, UCB

Modelling rheumatic heart disease progression in australia using disease register data linked to administrative records

Funding Acknowledgements

Type of funding sources: Public grant(s) – National budget only. Main funding source(s): Australian Government National Health and Medical Research Council

OnBehalf

ERASE project

Background

Rheumatic Heart Disease (RHD) is a major contributor to morbidity and mortality globally, and is endemic among Indigenous Australians. The RHD Endgame strategy was recently launched, outlining comprehensive methods for eliminating RHD in Australia by 2031. However, there is currently limited information on national rates of RHD and progression to severe or complicated RHD.

Purpose

This study provides current estimates of RHD progression prior to RHD Endgame Strategy implementation. We estimate the probability and predictors of progressing from RHD diagnosis to cardiovascular complications, death, or need for surgical intervention in the Australian population from expanded data sources, addressing methodological shortcomings in existing evidence by using cross-jurisdictional administrative datasets and a competing risks approach.

Methods

This retrospective cohort study used linked RHD register, hospital and death data from five Australian jurisdictions (&gt;70% Australians). Progression from RHD diagnosis to all-cause mortality, non-fatal cardiovascular complications (heart failure, stroke, endocarditis, atrial fibrillation), or need for surgical intervention were estimated for people aged &lt;35years diagnosed with first-ever RHD between 2010 and 2018. A minimum 8.5-year look-back excluded prevalent cases; maximum follow-up was 8 years. Proportional cause-specific hazard regression modelling investigated independent predictors of outcomes, with death treated as a competing risk.  Sensitivity analyses compared results between all-sources and register-only cohorts.

Results

We identified 1714 first-ever RHD cases aged &lt;35years in the all-sources cohort (84% Indigenous, 11% migrant, 63% women, 40% age 5-14years, 85% non-metropolitan). Six months after diagnosis, 8.1% (95%CI:6.9-9.5%) had experienced heart failure, other cardiovascular complications or surgical intervention and 23.6% (95%CI:20.2-27.5%) progressed to these outcomes within 8 years. The register-only cohort experienced less disease progression with estimated composite event rates of 5.6% (95%CI:4.7-6.6%) and 18.4% (95%CI:16.6-20.5%) at 6 month and 8 years respectively. Death rate in the all-sources cohort was 0.5% at 6 months and 3.2% at 8 years. Older age, Metropolitan residence, and history of acute rheumatic fever, but not sex or Indigenous status, were independent predictors of major cardiovascular outcomes.

Conclusions

This study provides the most definitive and contemporary estimates of RHD disease progression in young Australians. Despite Australia"s excellent healthcare system infrastructure, RHD complication rates remain high.  Improvements in healthcare systems for diagnosis, monitoring, and management of RHD cases will need to be implemented in both Metropolitan and remote settings as Australia implements its Endgame strategy against RHD. However, primordial and primary prevention provides the best potential to reduce the burden of RHD in Australia and beyond.

Cost-effectiveness of an indicated preventive intervention for depression in adolescents

Background

Adolescent depression has negative health and economic outcomes in the short- and long-term. Indicated preventive interventions, in particular group based cognitive behavioural therapy (GB-CBT), are effective in preventing depression in adolescents with subsyndromal depression. However, little is known about the cost-effectiveness of these interventions.

Methods

A Markov cohort model was used to conduct cost-effectiveness analyses comparing a GB-CBT indicated preventive intervention for depression, to a no-intervention option. Taking a time horizon of 5- and 10 years, incremental differences in societal costs and health benefits expressed as cases of depression prevented, and as quality adjusted life years (QALYs) gained were estimated. Through univariate and probabilistic sensitivity analyses, the robustness of the results was explored. Costs, presented in 2018 USD, and effects were discounted at a yearly rate of 3%.

Results

The base-case analysis showed that GB-CBT indicated preventive intervention incurred lower costs, prevented more cases of depression and generated higher QALYs compared to the no-intervention option for both time horizons. Offering the intervention was even a cost saving strategy and demonstrated a probability of being cost-effective of over 95%. In the sensitivity analyses, these results were robust to the modelling assumptions. Limitations: The study considered a homogeneous cohort and assumed a constant annual decay rate of the relative treatment effect.

Conclusions

GB-CBT indicated preventive interventions for depression in adolescence can generate good value for money compared to leaving adolescents with subsyndromal depression untreated.

Key messages

Indicated preventive interventions for depression are cost-saving and can generate substantial health benefits. Indicated preventive interventions can be adopted as cost-effective preventive strategies for depression.

Screening and treating pre-operative anaemia and suboptimal iron stores in elective colorectal surgery: a cost effectiveness analysis

Our study investigated whether pre-operative screening and treatment for anaemia and suboptimal iron stores in a patient blood management clinic is cost effective. We used outcome data from a retrospective cohort study comparing colorectal surgery patients admitted pre- and post-implementation of a pre-operative screening programme. We applied propensity score weighting techniques with multivariable regression models to adjust for differences in baseline characteristics between groups. Episode-level hospitalisation costs were sourced from the health service clinical costing data system; the economic evaluation was conducted from a Western Australia Health System perspective. The primary outcome measure was the incremental cost per unit of red cell transfusion avoided. We compared 441 patients screened in the pre-operative anaemia programme with 239 patients not screened; of the patients screened, 180 (40.8%) received intravenous iron for anaemia and suboptimal iron stores. The estimated mean cost of screening and treating pre-operative anaemia was AU$332 (£183; US$231; €204) per screened patient. In the propensity score weighted analysis, screened patients were transfused 52% less red cell units when compared with those not screened (rate ratio = 0.48, 95%CI 0.36-0.63, p < 0.001). The mean difference in total screening, treatment and hospitalisation cost between groups was AU$3776 lower in the group screened (£2080; US$2629; €2325) (95%CI AU$1604-5947, p < 0.001). Screening elective patients pre-operatively for anaemia and suboptimal iron stores reduced the number of red cell units transfused. It also resulted in lower total costs than not screening patients, thus demonstrating cost effectiveness.

Measurement of the Spectral Shape of the β-Decay of ^{137}Xe to the Ground State of ^{137}Cs in EXO-200 and Comparison with Theory

We report on a comparison between the theoretically predicted and experimentally measured spectra of the first-forbidden nonunique β-decay transition ^{137}Xe(7/2^{-})→^{137}Cs(7/2^{+}). The experimental data were acquired by the EXO-200 experiment during a deployment of an AmBe neutron source. The ultralow background environment of EXO-200, together with dedicated source deployment and analysis procedures, allowed for collection of a pure sample of the decays, with an estimated signal to background ratio of more than 99 to 1 in the energy range from 1075 to 4175 keV. In addition to providing a rare and accurate measurement of the first-forbidden nonunique β-decay shape, this work constitutes a novel test of the calculated electron spectral shapes in the context of the reactor antineutrino anomaly and spectral bump.

Search for Neutrinoless Double-β Decay with the Complete EXO-200 Dataset

A search for neutrinoless double-β decay (0νββ) in ^{136}Xe is performed with the full EXO-200 dataset using a deep neural network to discriminate between 0νββ and background events. Relative to previous analyses, the signal detection efficiency has been raised from 80.8% to 96.4±3.0%, and the energy resolution of the detector at the Q value of ^{136}Xe 0νββ has been improved from σ/E=1.23% to 1.15±0.02% with the upgraded detector. Accounting for the new data, the median 90% confidence level 0νββ half-life sensitivity for this analysis is 5.0×10^{25}  yr with a total ^{136}Xe exposure of 234.1 kg yr. No statistically significant evidence for 0νββ is observed, leading to a lower limit on the 0νββ half-life of 3.5×10^{25}  yr at the 90% confidence level.

P3783A higher habitual flavonoid intake is associated with a lower risk of atrial fibrillation

Background

Our understanding of how diet affects future risk of atrial fibrillation (AF) is limited. Evidence suggests that higher habitual intakes of flavonoids, bio-active compounds found in plant-based foods and beverages, lower cardiovascular disease risk, attenuate inflammation, and may have anti-arrhythmic properties.

Purpose

To investigate the association between flavonoid intake and clinically apparent AF in a large cohort of Danish men and women.

Methods

Baseline data from 55 634 participants without AF of the Danish Diet, Cancer and Health Study, recruited from 1993 to 1997, were cross-linked with Danish nationwide registries. Flavonoid intake was calculated from validated food frequency questionnaires using the Phenol-Explorer database. Associations between flavonoid intake and AF hospitalisation were examined using restricted cubic splines based on Cox proportional hazards models with adjustments for age, sex, BMI, smoking status, physical activity, alcohol intake, income, and hyperthyroidism.

Results

After a median [IQR] follow-up of 21 [18–22] years, 6 301 participants were hospitalised with AF. Non-linear associations were observed for total flavonoid intake and for all flavonoid sub-classes. For total flavonoid intake, after adjusting for potential lifestyle confounders and compared to participants in quintile 1 (median intake: 173 mg/day), those in quintile 3 (median intake: 320 mg/day) and quintile 4 (median intake: 494 mg/day) had a significantly lower risk of AF, with hazard ratios (95% CI) of 0.93 (0.87, 0.99) and 0.92 (0.86, 0.98), respectively. Compared to median intake in the lowest quintile, a total flavonoid intake of 1000 mg/day was associated with a lower risk of AF in smokers [0.86 (0.77, 0.96)] but not in non-smokers [0.96 (0.88, 1.05)], a lower risk of AF in high alcohol consumers [>20 g/d: 0.84 (0.75, 0.94)] but not in low-to-moderate alcohol consumers [<20 g/d: 0.97 (0.89, 1.06], a trending lower risk of AF in diabetics [0.76 (0.51, 1.14)] but not in non-diabetics [0.95 (0.89, 1.02)], and a trending lower risk of AF in those with ischaemic heart disease [0.84 (0.65, 1.09)] but not in those without [0.96 (0.89, 1.03), Figure 1].

Figure 1

Conclusion

We observed an inverse association between total flavonoid intake and AF, most notably in sub-populations with known lifestyle and disease risk factors for AF. This finding warrants investigation in randomised controlled trials. If confirmed, ensuring the adequate consumption of flavonoid-rich foods, particularly in individuals “at risk”, may be an important strategy to mitigate AF risk.

Acknowledgement/Funding

The Danish Diet, Cancer, and Health Study was funded by the Danish Cancer Society.

P3787Incidence, risk predictors, and mortality risk of new heart failure in an incident hospitalised atrial fibrillation cohort: a Western Australia population-based study, 2000–2010

Background

Atrial fibrillation (AF) is a risk factor for heart failure (HF) and new HF onset is associated with increased mortality.

Purpose

To determine the incidence, risk predictors and mortality risk of a new HF hospitalisation event in patients after incident AF hospital admission.

Methods

This was a contemporary, population-based retrospective cohort study which included all Western Australian residents, aged 25 to 94 years, who survived an incident hospitalisation for AF, between 2000 and 2010. Patients hospitalised with AF that had no previous AF or HF hospitalisations up to 15 years beforehand were identified. Time to first-ever HF hospitalisation in the three years following incident AF was assessed using Kaplan-Meier methods, accounting for all-cause death as a competing risk. Cox proportional hazards models were used to determine independent predictors of HF. The association of first HF with subsequent survival was estimated using a time-dependent HF variable with other risk covariates in a proportional hazards model.

Results

The cohort comprised of 34 999 patients, 56.8% male, with a mean age of 71.0 (SD 13.1) years. Females were on average 6 years older than males (P<0.001). Among the cohort, 20.4% had died from any cause at 3-year follow-up. The cumulative incidence of a first HF hospitalisation event at 3 years (n=4298), after accounting for death as a competing risk, was 12.3% (95% CI 11.9%-12.6%). Most HF hospitalisations (56.2%) occurred within the first year after incident AF admission (median of 279 days; IQR 64–649 days). Of the incident HF hospitalisations, 88.9% were an emergency admission. Independent predictors of an increased risk of HF hospitalisation included older age and a history of hypertension, diabetes, excessive alcohol consumption, myocardial infarction, chronic obstructive pulmonary disease, valvular heart disease, and chronic kidney disease (all P<0.0001). Incident AF patients who were hospitalised for first HF had an adjusted hazard ratio of 2.89 (95% CI; 2.71–3.08) for all-cause mortality (P<0.0001).

Conclusion

Hospitalisation for HF is a frequent and troublesome problem in patients after incident AF admission, and is independently associated with increased risk of mortality. The clinical predictors of new HF occurrence highlight the importance of assessment and comprehensive management of associated risk factors and comorbid diseases in order to prevent HF morbidity and mortality in AF patients.

Acknowledgement/Funding

NHMRC CRECOI Scholarship

Incorporating geography into a new generalized theoretical and statistical framework addressing the modifiable areal unit problem

Background

All analyses of spatially aggregated data are vulnerable to the modifiable areal unit problem (MAUP), which describes the sensitivity of analytical results to the arbitrary choice of spatial aggregation unit at which data are measured. The MAUP is a serious problem endemic to analyses of spatially aggregated data in all scientific disciplines. However, the impact of the MAUP is rarely considered, perhaps partly because it is still widely considered to be unsolvable.

Results

It was originally understood that a solution to the MAUP should constitute a comprehensive statistical framework describing the regularities in estimates of association observed at different combinations of spatial scale and zonation. Additionally, it has been debated how such a solution should incorporate the geographical characteristics of areal units (e.g. shape, size, and configuration), and in particular whether this can be achieved in a purely mathematical framework (i.e. independent of areal units). We argue that the consideration of areal units must form part of a solution to the MAUP, since the MAUP only manifests in their presence. Thus, we present a theoretical and statistical framework that incorporates the characteristics of areal units by combining estimates obtained from different scales and zonations. We show that associations estimated at scales larger than a minimal geographical unit of analysis are systematically biased from a true minimal-level effect, with different zonations generating uniquely biased estimates. Therefore, it is fundamentally erroneous to infer conclusions based on data that are spatially aggregated beyond the minimal level. Instead, researchers should measure and display information, estimate effects, and infer conclusions at the smallest possible meaningful geographical scale. The framework we develop facilitates this.

Conclusions

The proposed framework represents a new minimum standard in the estimation of associations using spatially aggregated data, and a reference point against which previous findings and misconceptions related to the MAUP can be understood.

Electronic supplementary material

The online version of this article (10.1186/s12942-019-0170-3) contains supplementary material, which is available to authorized users.

TM1-1 Seizure prophylaxis in gliomas (SPRING): a phase III randomised controlled trial comparing prophylactic levetiracetam versus no prophylactic anti-epileptic drug in glioma surgery

Objectives

There is no consensus regarding the need for prophylactic anti-epileptic drug (AED) in seizure-naive newly-diagnosed glioma patients. Data regarding prophylactic AED use are scant and inconclusive from older, small studies that enrolled patients with brain metastases, benign tumours and gliomas. A definitive randomised controlled trial (RCT) is needed to determine whether the policy of prophylactic AED therapy reduces the risk of first seizures in this population.

Design

Multi-centre RCT.

Subjects

Inclusion criteria: i. seizure-naive, ii. supratentorial glioma suitable for surgery (biopsy/resection), iii. age ≥16 years; iv. Karnofsky performance status >60.

Methods

Patients are randomised 1:1. Levetiracetam 500 mg bd for 2 weeks, increased to 750 mg bd thereafter for 1 year. Non-blinded. No placebo. Primary Outcome: one year risk of first seizure. Secondary outcomes: time to first seizure, time to first tonic-clonic seizure, mood, fatigue, quality of life, progression free survival, overall survival and incremental cost per QALY. Estimate of 1 year seizure rate in glioma after surgery is 20%. Based on a reduction in seizure rate to 10% a total of 806 patients will be recruited.

Results

Grant awarded by NIHR. Feasibility questionnaire demonstrated prophylactic AED rarely used. Neurosurgeons willing to randomise. 15 UK centres have expressed interest in participating.

Conclusions

SPRING will establish class I evidence for the use of seizure prophylaxis in glioma surgery. The trial will open to recruitment in January 2019.

Identical and Nonidentical Twins: Risk and Factors Involved in Development of Islet Autoimmunity and Type 1 Diabetes

OBJECTIVE

There are variable reports of risk of concordance for progression to islet autoantibodies and type 1 diabetes in identical twins after one twin is diagnosed. We examined development of positive autoantibodies and type 1 diabetes and the effects of genetic factors and common environment on autoantibody positivity in identical twins, nonidentical twins, and full siblings.

RESEARCH DESIGN AND METHODS

Subjects from the TrialNet Pathway to Prevention Study (N = 48,026) were screened from 2004 to 2015 for islet autoantibodies (GAD antibody [GADA], insulinoma-associated antigen 2 [IA-2A], and autoantibodies against insulin [IAA]). Of these subjects, 17,226 (157 identical twins, 283 nonidentical twins, and 16,786 full siblings) were followed for autoantibody positivity or type 1 diabetes for a median of 2.1 years.

RESULTS

At screening, identical twins were more likely to have positive GADA, IA-2A, and IAA than nonidentical twins or full siblings (all P < 0.0001). Younger age, male sex, and genetic factors were significant factors for expression of IA-2A, IAA, one or more positive autoantibodies, and two or more positive autoantibodies (all P ≤ 0.03). Initially autoantibody-positive identical twins had a 69% risk of diabetes by 3 years compared with 1.5% for initially autoantibody-negative identical twins. In nonidentical twins, type 1 diabetes risk by 3 years was 72% for initially multiple autoantibody-positive, 13% for single autoantibody-positive, and 0% for initially autoantibody-negative nonidentical twins. Full siblings had a 3-year type 1 diabetes risk of 47% for multiple autoantibody-positive, 12% for single autoantibody-positive, and 0.5% for initially autoantibody-negative subjects.

CONCLUSIONS

Risk of type 1 diabetes at 3 years is high for initially multiple and single autoantibody-positive identical twins and multiple autoantibody-positive nonidentical twins. Genetic predisposition, age, and male sex are significant risk factors for development of positive autoantibodies in twins.

Demonstration of differences in colonic volumes, transit, chyme consistency, and response to psyllium between healthy and constipated subjects using magnetic resonance imaging

BACKGROUND

In functional gastrointestinal disorders a lack of objective biomarkers limits evaluation of underlying mechanisms. We aimed to demonstrate the utility of magnetic resonance imaging for this task using psyllium, an effective constipation treatment, in patients and controls.

METHODS

Two crossover studies: (i) adults without constipation (controls, n = 9) took three treatments in randomized order for 6 days - maltodextrin (placebo), psyllium 3.5 g t.d.s and 7 g t.d.s., (ii) adults with chronic constipation (patients, n = 20) took placebo and psyllium 7 g t.d.s. for 6 days. MRI was performed fasting and postprandially on day 6. Measurements included small bowel and ascending colon water content, colonic volume, transit time, and MR relaxometry (T1, T2) to assess colonic chyme. Stool water percentage was measured.

RESULTS

7 g psyllium t.d.s. increased fasting colonic volumes in controls from median 372 mL (IQR 284-601) to 578 mL (IQR 510-882), and in patients from median 831 mL (IQR 745-934) to 1104 mL (847-1316), P < .05. Mean postprandial small bowel water was higher in controls and patients after 7 g psyllium t.d.s. vs placebo. Whole gut transit was slower in patients than controls (P < .05). T1 of the descending colon chyme (fasting) was lower in patients (213 ms, 176-420) than controls (440 ms, 352-884, P < .05) on placebo, but increased by 7 g psyllium t.d.s. (590 ms, 446-1338), P < .001. Descending colon T1 correlated with baseline stool water content and stool frequency on treatment.

CONCLUSIONS AND INFERENCES

MRI measurements can objectively demonstrate the mode of action of therapy targeting intestinal fluid content in constipation.

Comparative persistence of Salmonella and Escherichia coli O157:H7 in loam or sandy loam soil amended with bovine or swine manure

The fate of Salmonella and Escherichia coli O157:H7 in swine or dairy manure amended into sandy loam or loam soil under field conditions was studied. Soil was amended with manure inoculated with a Salmonella or E. coli O157:H7 cocktail, then transferred to 0.22 μm pore size membrane walled vials. The vials were then placed on the surface or at 15 cm depth in the test plots. Pathogen numbers, soil moisture, rainfall, and temperature were measured throughout the three trials (20-47 weeks duration) representing spring or fall application. Survival curves were characterized by having an initial rapid decline in pathogen numbers followed by a slower inactivation phase with an occasional increase in culturable cells. The CT_99.9 values (time to reach a 3 log CFU reduction) varied from 2 to 120 days, with the most rapid decrease being observed on the surface of sandy loam soil. The persistence of pathogens is primarily governed by variations in moisture and temperature, although season of application along with manure and soil type also contribute. To generate more accurate predictive pathogen models, there is a need for laboratory-based trials to mirror the dynamic variation in temperature and soil moisture encountered within the natural environment.

'Her cry is my cry': resettlement experiences of refugee women at risk recently resettled in Australia

OBJECTIVES

Refugee women entering resettlement countries on woman-at-risk visas represent a particularly vulnerable population. While their specific gender-based resettlement will likely differ from the general refugee population, little is known about their experiences of early resettlement, with which to inform resettlement policy and practice. This research aimed to explore lived experiences of recently resettled refugee women at risk in Australia.

STUDY DESIGN

Qualitative research used focus groups and a framework approach to identify and explicate common themes in participants' experience.

METHODS

Two focus groups with a purposive sample of African and Afghan refugee women at risk (N = 10), aged 22-53 years, were conducted in South East Queensland, Australia (October 2016), recruited with the assistance of a local resettlement service. Discussions were audiotaped, transcribed, and themes explicated.

RESULTS

Six superordinate themes emerged: (1) sentiment of gratitude; (2) sense of loneliness and disconnection; (3) feeling incapable; (4) experiencing distress and help-seeking; (5) experiencing financial hardship; and (6) anticipating the future.

CONCLUSIONS

Findings indicate that resettlement policy, programs, and practice that explicitly target the needs of women-at-risk refugees are warranted, including a longer period of active service provision with specific attention to strategies that address the women's social connection, self-efficacy, emotional well-being, and financial hardships.

Quality of life in adolescents with hepatitis C treated with sofosbuvir and ribavirin

Chronic HCV infection has been associated with impairment of HRQL in both adults and paediatric patients. Our aim was to assess the HRQL of HCV-positive children treated with SOF + RBV. The data for this post hoc analysis were collected in a phase 2 open-label multinational study that evaluated safety and efficacy of SOF (400 mg/day) plus RBV (weight-based up to 1400 mg/day) for 12 or 24 weeks in adolescents with chronic HCV (GS-US-334-1112). Patients and their parents/guardians completed the PedsQL-4.0-SF-15 questionnaire at baseline, at the end of treatment and in post-treatment follow-up. We included 50 adolescents with HCV genotype 2 and 3 without cirrhosis (14.8 ± 1.9 years; male: 58%; treatment-naïve: 82%; vertically transmitted HCV: 70%). After treatment, 100% of patients with HCV genotype 2 and 95% with genotype 3 achieved SVR-12. During treatment with SOF + RBV, there were no significant decrements in any of patients' self-reported or parent-proxy-reported PRO scores regardless of treatment duration (all P > .05). After treatment cessation, we recorded a statistically significant improvement in patients' self-reported Social Functioning score by post-treatment week 12: on average, +4.8 points on a 0-100 scale (P = .02). By post-treatment week 24, parent-proxy-reported School Functioning score increased by, on average, +13.0 points (P = .0065). In multivariate analysis, history of abdominal pain and psychiatric disorders were predictive of impaired HRQL in adolescents with HCV (P < .05). Adolescents with HCV do not seem to experience any HRQL decrement during treatment with SOF + RBV and experience some improvement of their HRQL scores after achieving SVR.

Targeting the Microbiota, from Irritable Bowel Syndrome to Mood Disorders: Focus on Probiotics and Prebiotics

PURPOSE OF REVIEW

The crosstalk between the gut and the brain has revealed a complex communication system responsible for maintaining a proper gastrointestinal homeostasis as well as affect emotional mood and cognitive functions. Recent research has revealed that beneficial manipulation of the microbiota by probiotics and prebiotics represent an emerging and novel strategy for the treatment of a large spectrum of diseases ranging from visceral pain to mood disorders. The review critically evaluates current knowledge of the effects exerted by both probiotics and prebiotics in irritable bowel syndrome (IBS) and mood disorders such as anxiety and depression.

RECENT FINDINGS

Relevant literature was identified through a search of MEDLINE via PubMed using the following words, "probiotics", "prebiotics", "microbiota", and "gut-brain axis" in combination with "stress", "depression", "IBS", and "anxiety". A number of trials have shown efficacy of probiotics and prebiotics in ameliorating both IBS related symptoms and emotional states. However, limitations have been found especially due to the small number of clinical studies, studies design, patient sample size, and placebo effect.

SUMMARY

Nonetheless, current finding supports the view that beneficial manipulation of the microbiota through both probiotics and prebiotics intake represents a novel attractive strategy to treat gut-brain axis disorders such as IBS and depression.

Postoperative Euglycaemic Diabetic Ketoacidosis Associated with Sodium–Glucose Cotransporter-2 Inhibitors (Gliflozins): A Report of Two Cases and Review of the Literature

Sodium–glucose cotransporter-2 inhibitor (SGLT2i)-associated euglycaemic diabetic ketoacidosis (euDKA) is a serious and increasingly recognised complication of treatment with this class of oral hypoglycaemic agents and can present a diagnostic challenge, resulting in delayed recognition, inappropriate treatment and potentially life-threatening acidosis. We present two cases of patients developing SGLT2i-associated euDKA in the early postoperative period. We support ceasing SGLT2i for 72 hours preoperatively and would suggest continuing to withhold the medication until oral intake is restored, and recommend a wider awareness of SGLT2i-associated diabetic ketoacidosis (DKA) amongst patients and their healthcare providers with an emphasis on checking ketone levels irrespective of blood glucose levels in the postoperative setting.

Inactivation of Listeria monocytogenes on and within Apples Destined for Caramel Apple Production by Using Sequential Forced Air Ozone Gas Followed by a Continuous Advanced Oxidative Process Treatment

This study evaluated the efficacy of using sequential forced air ozone followed by an advanced oxidative process (AOP) treatment to inactivate Listeria monocytogenes on and within Empire apples. The forced air ozone treatment consisted of a reactor that introduced ozone (6 g/h) into an airstream that flowed through an apple bed (ca. 30 cm in depth). Before treatment, the apples were conditioned at 4°C to ensure that condensate had formed before the apples were transferred to the reactor. The condensate ensured sufficient relative humidity to enhance the antimicrobial action of ozone. Air was passed through the apple bed at 9.3 m/s, and the ozone was introduced after 10 min. The ozone concentration measured after exiting the apple bed reached a steady state of 23 ppm. A 20-min ozone treatment supported a 2.12- to 3.07-log CFU reduction of L. monocytogenes, with no significant effect of apple position within the bed. The AOP-based method was a continuous process whereby hydrogen peroxide was introduced as a vapor into a reactor illuminated by UV-C and ozone-emitting lamps that collectively generated hydroxyl radicals. Operating the AOP reactor with UV-C light (54-mJ cm² dose), 6% (v/v) hydrogen peroxide, 2 g/h ozone, and a chamber temperature of 48°C resulted in a 3-log CFU reduction of L. monocytogenes on the surface of the apples and internally within the scar tissue. Applying a caramel coating, from a molten solution (at 80°C), resulted in a 0.5-log CFU reduction of L. monocytogenes on the apple surface. In apples treated with the sequential process, L. monocytogenes could only be recovered sporadically by enrichment and did not undergo outgrowth when the caramel apples were stored at 22°C for 19 days. However, growth of L. monocytogenes within the core, but not the surface, was observed from caramel apples prepared from nontreated control fruit.

Structure-based inhibitors of tau aggregation

Aggregated tau protein is associated with over 20 neurological disorders, which include Alzheimer's disease. Previous work has shown that tau's sequence segments VQIINK and VQIVYK drive its aggregation, but inhibitors based on the structure of the VQIVYK segment only partially inhibit full-length tau aggregation and are ineffective at inhibiting seeding by full-length fibrils. Here we show that the VQIINK segment is the more powerful driver of tau aggregation. Two structures of this segment determined by the cryo-electron microscopy method micro-electron diffraction explain its dominant influence on tau aggregation. Of practical significance, the structures lead to the design of inhibitors that not only inhibit tau aggregation but also inhibit the ability of exogenous full-length tau fibrils to seed intracellular tau in HEK293 biosensor cells into amyloid. We also raise the possibility that the two VQIINK structures represent amyloid polymorphs of tau that may account for a subset of prion-like strains of tau.

Constructing longitudinal disease progression curves using sparse, short-term individual data with an application to Alzheimer's disease

In epidemiology, cohort studies utilised to monitor and assess disease status and progression often result in short-term and sparse follow-up data. Thus, gaining an understanding of the full-term disease pathogenesis can be difficult, requiring shorter-term data from many individuals to be collated. We investigate and evaluate methods to construct and quantify the underlying long-term longitudinal trajectories for disease markers using short-term follow-up data, specifically applied to Alzheimer's disease. We generate individuals' follow-up data to investigate approaches to this problem adopting a four-step modelling approach that (i) determines individual slopes and anchor points for their short-term trajectory, (ii) fits polynomials to these slopes and anchor points, (iii) integrates the reciprocated polynomials and (iv) inverts the resulting curve providing an estimate of the underlying longitudinal trajectory. To alleviate the potential problem of roots of polynomials falling into the region over which we integrate, we propose the use of non-negative polynomials in Step 2. We demonstrate that our approach can construct underlying sigmoidal trajectories from individuals' sparse, short-term follow-up data. Furthermore, to determine an optimal methodology, we consider variations to our modelling approach including contrasting linear mixed effects regression to linear regression in Step 1 and investigating different orders of polynomials in Step 2. Cubic order polynomials provided more accurate results, and there were negligible differences between regression methodologies. We use bootstrap confidence intervals to quantify the variability in our estimates of the underlying longitudinal trajectory and apply these methods to data from the Alzheimer's Disease Neuroimaging Initiative to demonstrate their practical use. Copyright © 2017 John Wiley & Sons, Ltd.