3,698 research outputs found
Identifying mechanisms of change in a conversation therapy for aphasia using behaviour change theory and qualitative methods
BACKGROUND: Conversation therapy for aphasia is a complex intervention comprising multiple components and targeting multiple outcomes. UK Medical Research Council (MRC) guidelines published in 2008 recommend that in addition to measuring the outcomes of complex interventions, evaluation should seek to clarify how such outcomes are produced, including identifying the hypothesized mechanisms of change. AIMS: To identify mechanisms of change within a conversation therapy for people with aphasia and their partners. Using qualitative methods, the study draws on behaviour change theory to understand how and why participants make changes in conversation during and after therapy. METHODS & PROCEDURES: Data were derived from 16 participants (eight people with aphasia; eight conversation partners) who were recruited to the Better Conversations with Aphasia research project and took part in an eight session conversation therapy programme. The dataset consists of in-therapy discussions and post-therapy interviews, which are analysed using Framework Analysis. OUTCOMES & RESULTS: Seven mechanisms of conversational behaviour change are identified and linked to theory. These show how therapy can activate changes to speakers' skills and motivation for using specific behaviours, and to the conversational opportunities available for strategy use. CONCLUSIONS & IMPLICATIONS: These clinically relevant findings offer guidance about the processes involved in producing behavioural change via conversation therapy. A distinction is made between the process involved in motivating change and that involved in embedding change. Differences are also noted between the process engaged in reducing unhelpful behaviour and that supporting new uses of compensatory strategies. Findings are expected to have benefits for those seeking to replicate therapy's core processes both in clinical practice and in future research
Assessing trustworthiness of digital information
This paper reports the key findings of an empirical study conducted with undergraduate students to identify and assess the core constructs of online trust, with a focus on health digital information. This study suggests the use of a trust scale in further research into the potential impact of the system and information design on the usersâ trust and use of digital information
Early virological response to HIV treatment: can we predict who is likely to experience subsequent treatment failure? Results from an observational cohort study, London, UK
INTRODUCTION: For people living with HIV, the first antiretroviral treatment (ART) regimen offers the best chance for a good virological response. Early identification of those unlikely to respond to firstâline ART could enable timely intervention and increase chances of a good initial treatment response. In this study we assess the extent to which the HIV RNA viral load (VL) at 1 and 3 months is predictive of firstâline treatment outcome at 6 months. METHODS: All previously ARTânaive individuals starting ART at two London centres since 2000 with baseline (â180 to 3 days) VL >500 c/mL had a VL measurement between 6 and 12 months after starting ART, and at least one at month 1 (4â60 days) or month 3 (61â120 days) were included. Lack of treatment response was defined as (i) VL >200 copies/mL at 6 months or (ii) VL >200 copies/mL at 6 months or simultaneous switch in drugs from at least two different drug classes before 6 months. The association with VL measurements at 1 and 3 months postâART; change from preâART in these values; and CD4 count measurements at 1 and 3 months were assessed using logistic regression models. The relative fit of the models was compared using the Akaike information criterion (AIC). RESULTS: A total of 198 out of 3258 individuals (6%) experienced lack of treatment response at 6 months (definition i), increasing to 511 (16%) for definition (ii). Those with a 1âmonth (day 4â60 window) VL of 100,000 copies/ml had a 4%, 8%, 23% and 24% chance, respectively, of subsequently experiencing treatment nonâresponse at 6 months (definition (i)). When considering the 3âmonth (day 61â120 window) VL, the chances of subsequently experiencing treatment nonâresponse were, respectively, 3%, 25%, 67% and 75%. Results were similar for definition (ii). CONCLUSIONS: Whilst 3âmonth VL provides good discrimination between low and high risk of treatment failure, 1âmonth VL does not. Presence of a VL >10,000 copies/ml after 3 months of ART is a cutoff above which individuals are at a sufficiently higher risk of nonâresponse that they may be considered for intervention
All-cause hospitalisation according to demographic group in people living with HIV in the current ART era: Recent findings from a cohort study in the UK
OBJECTIVE: We investigated differences in all-cause hospitalisation between key demographic groups among people with HIV in the UK in the current ART era. DESIGN/METHODS: We used data from the Royal Free HIV Cohort study between 2007 and 2018. Individuals were classified into five groups: men who have sex with men (MSM), Black African men who have sex with women (MSW), MSW of other ethnicity, Black African women and women of other ethnicity. We studied hospitalisations during the first year after HIV diagnosis (Analysis-A) separately from those more than one year after diagnosis (Analysis-B). In Analysis-A, time to first hospitalisation was assessed using Cox regression adjusted for age and diagnosis date. In Analysis-B, subsequent hospitalisation rate was assessed using Poisson regression, accounting for repeated hospitalisation within individuals, adjusted for age, calendar year, time since diagnosis. RESULTS: The hospitalisation rate was 30.7/100 person-years in the first year after diagnosis and 2.7/100 person-years subsequently; 52% and 13% hospitalisations respectively were AIDS-related. Compared to MSM, MSW and women were at much higher risk of hospitalisation during the first year [aHR (95%CI): 2.7 (1.7-4.3), 3.0 (2.0-4.4), 2.0 (1.3-2.9), 3.0 (2.0-4.5) for Black African MSW; other ethnicity MSW; Black African women; other ethnicity women respectively, Analysis-A] and remained at increased risk subsequently [corresponding aIRR (95% CI): 1.7 (1.2-2.4), 2.1 (1.5-2.8), 1.5 (1.1-1.9), 1.7 (1.2-2.3), Analysis-B]. CONCLUSIONS: In this setting with universal healthcare, substantial variation exists in hospitalisation risk across demographic groups, both in early and subsequent periods after HIV diagnosis, highlighting the need for targeted interventions
The molecular characterisation of Escherichia coli K1 isolated from neonatal nasogastric feeding tubes
Background: The most common cause of Gram-negative bacterial neonatal meningitis is E. coli K1. It has a mortality rate of 10â15%, and neurological sequelae in 30â 50% of cases. Infections can be attributable to nosocomial sources, however the pre-colonisation of enteral feeding tubes has not been considered as a specific risk factor. Methods: Thirty E. coli strains, which had been isolated in an earlier study, from the residual lumen liquid and biofilms of neonatal nasogastric feeding tubes were genotyped using pulsed-field gel electrophoresis, and 7-loci multilocus sequence typing. Potential pathogenicity and biofilm associated traits were determined using specific PCR probes, genome analysis, and in vitro tissue culture assays. Results: The E. coli strains clustered into five pulsotypes, which were genotyped as sequence types (ST) 95, 73, 127, 394 and 2076 (Achman scheme). The extra-intestinal pathogenic E. coli (ExPEC) phylogenetic group B2 ST95 serotype O1:K1:NM strains had been isolated over a 2 week period from 11 neonates who were on different feeding regimes. The E. coli K1 ST95 strains encoded for various virulence traits associated with neonatal meningitis and extracellular matrix formation. These strains attached and invaded intestinal, and both human and rat brain cell lines, and persisted for 48 h in U937 macrophages. E. coli STs 73, 394 and 2076 also persisted in macrophages and invaded Caco-2 and human brain cells, but only ST394 invaded rat brain cells. E. coli ST127 was notable as it did not invade any cell lines. Conclusions: Routes by which E. coli K1 can be disseminated within a neonatal intensive care unit are uncertain, however the colonisation of neonatal enteral feeding tubes may be one reservoir source which could constitute a serious health risk to neonates following ingestion
Stability Analysis of Frame Slotted Aloha Protocol
Frame Slotted Aloha (FSA) protocol has been widely applied in Radio Frequency
Identification (RFID) systems as the de facto standard in tag identification.
However, very limited work has been done on the stability of FSA despite its
fundamental importance both on the theoretical characterisation of FSA
performance and its effective operation in practical systems. In order to
bridge this gap, we devote this paper to investigating the stability properties
of FSA by focusing on two physical layer models of practical importance, the
models with single packet reception and multipacket reception capabilities.
Technically, we model the FSA system backlog as a Markov chain with its states
being backlog size at the beginning of each frame. The objective is to analyze
the ergodicity of the Markov chain and demonstrate its properties in different
regions, particularly the instability region. By employing drift analysis, we
obtain the closed-form conditions for the stability of FSA and show that the
stability region is maximised when the frame length equals the backlog size in
the single packet reception model and when the ratio of the backlog size to
frame length equals in order of magnitude the maximum multipacket reception
capacity in the multipacket reception model. Furthermore, to characterise
system behavior in the instability region, we mathematically demonstrate the
existence of transience of the backlog Markov chain.Comment: 14 pages, submitted to IEEE Transaction on Information Theor
Opposing associations of depression with sexual behaviour: implications for epidemiological investigation among gay, bisexual and other men who have sex with men
OBJECTIVE: The aim of this report is to investigate the nature of the relationship between depression and condomless sex (CLS) among gay, bisexual and other men who have sex with men (GBMSM). METHODS: Data are from the Antiretrovirals, Sexual Transmission Risk and Attitude (ASTRA) study of people living with HIV and attending one of eight HIV outpatient clinics in England (2011-2012) and the Attitudes to and Understanding of Risk of Acquisition of HIV (AURAH) study of HIV-negative/unknown status individuals attending one of 20 genitourinary medicine clinics in England (2013-2014). This analysis included GBMSM only. For each study, the prevalence of depressive symptoms (Patient Health Questionnaire-9 score â„10) was presented according to three categories of sex in the past 3âmonths (considering anal/vaginal sex with men/women and anal sex with men in separate definitions): (1) no sex, (2) condom-protected sex only and (3) CLS. Multinomial logistic regression with 'condom-protected sex only' as the reference group was used to adjust for age and (for ASTRA participants) time since HIV diagnosis. RESULTS: There were opposing associations of depression with recent sexual behaviour: the prevalence of depression was higher among those who reported no sex and those who reported CLS, compared with those who reported condom-protected sex only. Among the 2170 HIV-positive GBMSM in ASTRA, considering anal/vaginal sex with men/women, the prevalence of depressive symptoms was 32%, 20% and 28%, respectively, among men reporting no sex (n=783), condom-protected sex only (n=551) and CLS (n=836) (global p<0.001). Among the 1477 HIV-negative GBMSM in AURAH, the prevalence of depressive symptoms was 12%, 8% and 13%, respectively, for no sex (n=137), condom-protected sex only (n=487) and CLS (n=853) (global p=0.017). Patterns were similar after adjustment and when only considering anal sex between men. CONCLUSIONS: Depression may be linked both to lack of sexual activity and to sexual risk taking. When investigating associations between depression and CLS, it is important to separate out individuals reporting condom-protected sex only from those reporting no sex
Non-Disclosure of HIV Status and Associations with Psychological Factors, ART Non-Adherence, and Viral Load Non-Suppression Among People Living with HIV in the UK
Disclosure of HIV status to family, friends, and a stable partner may be linked to improved health outcomes for people living with HIV. This study assessed whether non-disclosure is associated with psychological symptoms, non-adherence to antiretroviral therapy (ART), and viral load (VL) non-suppression. A total of 3258 HIV-diagnosed individuals in the UK completed the confidential ASTRA study questionnaire (2011-2012). Participants reported whether they told anyone they had HIV; to which confidant(s) (friends, family, work colleagues, stable partner) and to what extent (none, some, most/all). The prevalence and factors associated with non-disclosure were assessed. Associations between non-disclosure and the following factors were established using modified Poisson regression with adjustment for socio-demographic factors (gender, age group, ethnicity), HIV-related factors (time since HIV diagnosis, ART status), and clinic: low social support (score â€Â 12 on modified Duke-UNC FSSQ); depression and anxiety symptoms (â„10 on PHQ-9 and GAD-7 respectively); self-reported ART non-adherence in past 2 weeks/3 months; VL non-suppression (clinic-recorded VL > 50 copies/mL among those who started ART â„ 6 months ago). Among 3233 participants with disclosure data, the prevalence of non-disclosure to anyone was 16.6 % (n/N = 61/367) among heterosexual men, 15.7 % (98/626) among women, and 5.0 % (113/2240) among MSM. MSM were more likely to disclose to some/all friends compared to family (85.8 vs. 59.9 %) while heterosexuals were less likely to disclose to friends than family (44.1 vs. 61.1 % for men, 57.5 vs. 67.1 % for women). Among 1,631 participants with a stable partner, non-disclosure to a stable partner was 4.9 % for MSM, 10.9 % for heterosexual men, and 13.0 % for women. In adjusted analyses, older age (â„60 years), non-white ethnicity, more recent HIV diagnosis, and not having a stable partner were significantly associated with overall non-disclosure for MSM and heterosexual individuals. The prevalence of low social support was 14.4 %, of depression and anxiety symptoms 27.1 and 22.0 %, respectively, of ART non-adherence 31.8 %, and of viral load non-suppression on ART 9.8 %. There was no evidence that non-disclosure overall (versus disclosure to anyone) was associated with low social support, depression or anxiety symptoms, ART non-adherence or VL non-suppression among MSM or heterosexual individuals. However, compared to MSM who disclosed to 'none' or 'some' friends and family, MSM who disclosed to 'most or all' of their friends and family were more likely to have symptoms of depression (adjusted PR = 1.4, 95 % CI 1.2-1.7), anxiety (1.3, 1.1-1.6), and to report ART non-adherence (1.3, 1.1-1.5). In this large multicentre study of people living with HIV in the UK, non-disclosure was overall low, but higher for heterosexual individuals compared to MSM. Non-disclosure was not associated with higher prevalence of adverse health measures
Prospective association of social circumstance, socioeconomic, lifestyle and mental health factors with subsequent hospitalisation over 6â7 year follow up in people living with HIV
Background: Predictors of hospitalisation in people with HIV (PLHIV) in the contemporary treatment era are not well understood. /
Methods: This ASTRA sub-study used clinic data linkage and record review to determine occurrence of hospitalisations among 798 PLHIV from baseline questionnaire (February to December 2011) until 1 June 2018. Associations of baseline social circumstance, socioeconomic, lifestyle, mental health, demographic and clinical factors with repeated all-cause hospitalisation from longitudinal data were investigated using Prentice-Williams-Peterson models. Associations were also assessed in 461 individuals on antiretroviral therapy (ART) with viral load â€50 copies/ml and CD4 count â„500 cells/ ”l. /
Findings: Rate of hospitalisation was 5.8/100 person-years (95% CI: 5.1â6.5). Adjusted for age, demographic group and time with diagnosed HIV, the following social circumstance, socioeconomic, lifestyle and mental health factors predicted hospitalisation: no stable partner (adjusted hazard ratio (aHR)=1.59; 95% CI=1.16â2.20 vs living with partner); having children (aHR=1.50; 1.08â2.10); non-employment (aHR=1.56; 1.07â2.27 for unemployment; aHR=2.39; 1.70â3.37 for sick/disabled vs employed); rented housing (aHR=1.72; 1.26â2.37 vs homeowner); not enough money for basic needs (aHR=1.82; 1.19â2.78 vs enough); current smoking (aHR=1.39; 1.02â1.91 vs never); recent injection-drug use (aHR=2.11; 1.30â3.43); anxiety symptoms (aHRs=1.39; 1.01â1.91, 2.06; 1.43â2.95 for mild and moderate vs none/minimal); depressive symptoms (aHRs=1.67; 1.17â2.38, 1.91; 1.30â2.78 for moderate and severe vs none/minimal); treated/untreated depression (aHRs=1.65; 1.03â2.64 for treated depression only, 1.87; 1.39â2.52 for depressive symptoms only; 1.53; 1.05â2.24; for treated depression and depressive symptoms, versus neither). Associations were broadly similar in those with controlled HIV and high CD4. /
Interpretation: Social circumstance, socioeconomic disadvantage, adverse lifestyle factors and poorer mental health are strong predictors of hospitalisation in PLHIV, highlighting the need for targeted interventions and care. /
Funding: British HIV Association (BHIVA) Research Award (2017); SMR funded by a PhD fellowship from the Royal Free Charity
Alcohol, smoking, recreational drug use and association with virological outcomes among people living with HIV: cross-sectional and longitudinal analyses
Objectives:
There is increasing evidence to suggest that people living with HIV (PLWH) have significant morbidity from alcohol, recreational drug use and cigarette smoking. Our aim was to report associations of these factors with antiretroviral therapy (ART) non-adherence, viral non-suppression and subsequent viral rebound in PLWH. /
Methods:
The Antiretroviral Sexual Transmission Risk and Attitudes (ASTRA) study recruited PLWH attending eight outpatient clinics in England between February 2011 and December 2012. Data included self-reported excessive drinking (estimated consumption of > 20 units of alcohol/week), alcohol dependency (CAGE score â„ 2 with current alcohol consumption), recreational drug use (including injection drug use in the past 3 months), and smoking status. Among participants established on ART, cross-sectional associations with ART non-adherence [missing â„2 consecutive days of ART on â„2 occasions in the past three months] and viral-non suppression [viral load (VL) > 50 copies/mL] were assessed using logistic regression. In participants from one centre, longitudinal associations with subsequent viral rebound (first VL > 200 copies/mL) in those on ART with VL †50 copies/mL at baseline were assessed using Cox regression during a 7-year follow-up. /
Results:
Among 3258 PLWH, 2248 (69.0%) were men who have sex with men, 373 (11.4%) were heterosexual men, and 637 (19.6%) were women. A CAGE score â„ 2 was found in 568 (17.6%) participants, 325 (10.1%) drank > 20 units/week, 1011 (31.5%) currently smoked, 1242 (38.1%) used recreational drugs and 74 (2.3%) reported injection drug use. In each case, prevalence was much more common among men than among women. Among 2459 people on ART who started at least 6 months previously, a CAGE score â„ 2, drinking > 20 units per week, current smoking, injection and non-injection drug use were all associated with ART non-adherence. After adjusting for demographic and socioeconomic factors, CAGE score â„ 2 [adjusted odds ratio (aOR) = 1.52, 95% confidence interval (CI): 1.09â2.13], current smoking (aOR = 1.58, 95% CI: 1.10â2.17) and injection drug use (aOR = 2.11, 95% CI: 1.00â4.47) were associated with viral non-suppression. During follow-up of a subset of 592 people virally suppressed at recruitment, a CAGE score â„ 2 [adjusted hazard ratio (aHR) = 1.66, 95% CI: 1.03â2.74], use of 3 or more non-injection drugs (aHR = 1.82, 95% CI: 1.12â3.57) and injection drug use (aHR = 2.73, 95% CI: 1.08â6.89) were associated with viral rebound. /
Conclusions:
Screening and treatment for alcohol, cigarette and drug use should be integrated into HIV outpatient clinics, while clinicians should be alert to the potential for poorer virological outcomes
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