Your browser doesn't support javascript.
loading
Mostrar: 20 | 50 | 100
Resultados 1 - 20 de 31
Filtrar
1.
Int J Drug Policy ; : 104324, 2024 Jan 12.
Artigo em Inglês | MEDLINE | ID: mdl-38218700

RESUMO

BACKGROUND: In England, over 80 % of those with hepatitis C virus (HCV) infection have injected drugs. We quantified the HCV cascade of care (CoC) among people who inject drugs (PWID) in England and determined whether this improved after direct-acting antivirals (DAAs) were introduced. METHODS: We analysed data from nine rounds of national annual cross-sectional surveys of PWID recruited from drug services (2011-2019; N = 12,320). Study rounds were grouped as: 'Pre-DAAs' (2011-2014), 'Prioritised DAAs' (2015-2016) and 'Unrestricted DAAs' (2017-2019). Participants were anonymously tested for HCV antibodies and RNA and completed a short survey. We assessed the proportion of PWID recently (current/previous year) tested for HCV. For participants ever HCV treatment eligible (past chronic infection with history of treatment or current chronic infection), we assessed the CoC as: HCV testing (ever), received a positive test result, seen a specialist nurse/doctor, and ever treated. We used logistic regression to determine if individuals progressed through the CoC differently depending on time-period, whether time-period was associated with recent testing (all participants) and lifetime HCV treatment (ever eligible participants), and predictors of HCV testing and treatment in the Unrestricted DAAs period. RESULTS: The proportion of ever HCV treatment eligible PWID reporting lifetime HCV treatment increased from 12.5 % in the Pre-DAAs period to 25.6 % in the Unrestricted DAAs period (aOR:2.40, 95 %CI:1.95-2.96). There were also increases in seeing a specialist nurse/doctor. The largest loss in the CoC was at treatment for all time periods. During the Unrestricted DAAs period, recent (past year) homelessness (vs never, aOR:0.66, 95 %CI:0.45-0.97), duration of injecting (≤3 years vs >3 years; aOR:0.26, 95 %CI:0.12-0.60), never (vs current, aOR:0.31, 95 %CI:0.13-0.75) or previously being prescribed OAT (vs current, aOR:0.67, 95 %CI:0.47-0.95), and never using a NSP (vs past year, aOR:0.27, 95 %CI:0.08-0.89) were negatively associated with lifetime HCV treatment. The proportion of PWID reporting recent HCV testing was higher during Unrestricted DAAs (56 %) compared to Pre-DAAs (48 %; aOR:1.28, 95 %CI:1.06-1.54). CONCLUSION: COC stages from seeing a specialist onwards improved after DAAs became widely available. Further improvements in HCV testing are needed to eliminate HCV in England.

2.
J Infect ; 85(6): 676-682, 2022 12.
Artigo em Inglês | MEDLINE | ID: mdl-36170895

RESUMO

BACKGROUND: Elimination targets for hepatitis C have been set across the world. In the UK almost 90% of infections are in people who inject drugs. Evidence shows community case-finding is effective at identifying and treating undiagnosed patients. The aim of this analysis was to assess, from a healthcare provider perspective, the cost-effectiveness of a new pharmacist-led test and treat pathway for hepatitis C in opioid agonist treatment (OAT) patients attending community pharmacies compared to conventional care. METHODS: In a cluster randomised controlled trial, pharmacies were randomised to the pharmacist-led or conventional care pathway. Mean cost per OAT patient and per patient initiating treatment was identified for each pathway. A Markov model tracking disease progression was developed, with a 50-year time horizon and 3·5% time discount rate, to estimate the incremental cost-effectiveness ratio (ICER) per quality-adjusted life-year (QALY) gained and the probability of being cost-effective at a £30,000 per QALY willingness-to-pay threshold. Probabilistic sensitivity analysis was performed for a range of drug discounts, re-infection rates, and model assumptions. FINDINGS: Mean cost per OAT patient (£3,674 vs £1,965) and per patient initiating treatment (£863 vs £404) was higher in the pharmacist-led pathway, due to higher uptake of testing and pharmacist time requirements. Over a 50-year time horizon the ICER per QALY gained was £31,612 at NHS indicative price for treatment (£38,979 for 12 weeks) and 12·1/100 person-years re-infection rate, reducing to £21,027/£10,220/-£501 per QALY gained with 30%/60%/90% drug price discounts and £25,373/£21,738/£14,912 per QALY gained at re-infection rates of 8/5/2 per 100 person-years. At 30%/60%/90% drug discount rates, the pharmacist-led pathway has an 80%/98%/100% probability of being cost-effective. INTERPRETATION: The pharmacist-led pathway is effective at increasing testing and treatment uptake, with cost-effectiveness being highly dependent on drug price discounts. FUNDING: Trial funding provided by the Scottish Government, Gilead Sciences, and Bristol-Myers Squibb.


Assuntos
Hepatite C , Farmácias , Farmácia , Humanos , Análise Custo-Benefício , Antivirais/uso terapêutico , Tratamento de Substituição de Opiáceos , Reinfecção , Hepatite C/tratamento farmacológico , Hepacivirus , Anos de Vida Ajustados por Qualidade de Vida
3.
HIV Med ; 22(4): 262-272, 2021 04.
Artigo em Inglês | MEDLINE | ID: mdl-33179855

RESUMO

OBJECTIVES: There is a high prevalence of HIV (5.2% in 2018) among men who have sex with men (MSM) in Ukraine. HIV testing, condom provision and facilitated linkage to HIV treatment have been funded by various bodies through non-governmental organizations (NGOs). We investigated whether contact with these NGOs was associated with improved prevention and treatment outcomes among MSM in Ukraine. METHODS: Data were taken from four rounds of integrated bio-behavioural surveys among MSM in Ukraine (2011, N = 5950; 2013, N = 8101; 2015, N = 4550; 2018, N = 5971) including HIV testing combined with questionnaire responses. Data were analysed using mixed-effect regression models, which estimated associations between being an NGO client and behavioural, HIV testing and HIV treatment outcomes, adjusted for demographic factors. RESULTS: Those MSM who were NGO clients were more likely than non-clients to have been HIV tested in the last year [adjusted odds ratio (aOR) = 7.01, 95% confidence interval (CI): 6.45-7.62] or ever (aOR = 11.00, 95% CI: 9.77-12.38), to have used a condom for the last anal sex act (aOR = 1.32, 95% CI: 1.21-1.43), and to have recently either bought or received condoms (aOR = 21.27, 95% CI: 18.01-25.12). HIV-positive MSM were more likely to have contact with NGOs (aOR = 1.61, 95% CI: 1.39-1.86). Among the HIV-positive MSM, those who were NGO clients were more likely to be registered at an AIDS centre (aOR = 2.24, 95% CI: 1.61-3.11) and to be on antiretroviral treatment (aOR = 2.20, 95% CI: 1.51-3.20). CONCLUSIONS: In Ukraine, being in contact with MSM-targeted NGOs is associated with better outcomes for HIV prevention, testing and treatment, suggesting that NGO harm reduction projects for MSM have had a beneficial impact on reducing HIV transmission and morbidity.


Assuntos
Infecções por HIV , Minorias Sexuais e de Gênero , Estudos Transversais , Infecções por HIV/tratamento farmacológico , Infecções por HIV/epidemiologia , Infecções por HIV/prevenção & controle , Redução do Dano , Homossexualidade Masculina , Humanos , Masculino
4.
Trop Med Int Health ; 25(10): 1235-1245, 2020 10.
Artigo em Inglês | MEDLINE | ID: mdl-32737914

RESUMO

OBJECTIVES: Scaling up of point-of-care testing (POCT) for early infant diagnosis of HIV (EID) could reduce the large gap in infant testing. However, suboptimal POCT EID could have limited impact and potentially high avoidable costs. This study models the cost-effectiveness of a quality assurance system to address testing performance and screening interruptions, due to, for example, supply stockouts, in Kenya, Senegal, South Africa, Uganda and Zimbabwe, with varying HIV epidemics and different health systems. METHODS: We modelled a quality assurance system-raised EID quality from suboptimal levels: that is, from misdiagnosis rates of 5%, 10% and 20% and EID testing interruptions in months, to uninterrupted optimal performance (98.5% sensitivity, 99.9% specificity). For each country, we estimated the 1-year impact and cost-effectiveness (US$/DALY averted) of improved scenarios in averting missed HIV infections and unneeded HIV treatment costs for false-positive diagnoses. RESULTS: The modelled 1-year costs of a national POCT quality assurance system range from US$ 69 359 in South Africa to US$ 334 341 in Zimbabwe. At the country level, quality assurance systems could potentially avert between 36 and 711 missed infections (i.e. false negatives) per year and unneeded treatment costs between US$ 5808 and US$ 739 030. CONCLUSIONS: The model estimates adding effective quality assurance systems are cost-saving in four of the five countries within the first year. Starting EQA requires an initial investment but will provide a positive return on investment within five years by averting the costs of misdiagnoses and would be even more efficient if implemented across multiple applications of POCT.


OBJECTIFS: L'intensification du dépistage au point des soins (DPS) pour le diagnostic précoce du VIH chez le nourrisson (DPVN) pourrait réduire le grand écart dans le dépistage des nourrissons. Cependant, un DPVN DPS sous-optimal pourrait avoir un impact limité et des coûts évitables potentiellement élevés. Cette étude modélise la rentabilité d'un système d'assurance qualité pour traiter les performances des tests et les interruptions de dépistage, dues par exemple à des ruptures de stock, au Kenya, au Sénégal, en Afrique du Sud, en Ouganda et au Zimbabwe, avec des épidémies variables du VIH et des systèmes de santé différents. MÉTHODES: Nous avons modélisé une qualité de DPVN soulevée par le système d'assurance qualité à partir de niveaux sous-optimaux: c'est-à-dire des taux d'erreurs de diagnostic de 5%, 10% et 20% et des interruptions des tests de DPVN en mois, à des performances optimales ininterrompues (sensibilité de 98,5%, spécificité de 99,9%). Pour chaque pays, nous avons estimé l'impact sur un an et la rentabilité (en USD/DALY évitée) de scénarios améliorés pour éviter les infections à VIH manquées et les coûts inutiles de traitement du VIH pour les diagnostics faux positifs. RÉSULTATS: Les coûts modélisés sur un an d'un système national d'assurance qualité DPS vont de 69.359 USD en Afrique du Sud à 334.341 USD au Zimbabwe. Au niveau des pays, les systèmes d'assurance de la qualité pourraient potentiellement éviter entre 36 et 711 infections manquées (c'est-à-dire des faux négatifs) par an et des coûts de traitement inutiles entre 5.808 et 739.030 USD. CONCLUSIONS: Le modèle estime que l'ajout de systèmes d'assurance qualité efficaces permet de réaliser des économies dans quatre des cinq pays au cours de la première année. Le lancement de l'assurance qualité nécessite un investissement initial, mais fournira un retour sur investissement positif dans les cinq ans en évitant les coûts des diagnostics erronés et serait encore plus efficace s'il était mis en œuvre dans plusieurs applications de DPS.


Assuntos
Serviços de Saúde da Criança/estatística & dados numéricos , Diagnóstico Precoce , Infecções por HIV/epidemiologia , Testes Imediatos/estatística & dados numéricos , Garantia da Qualidade dos Cuidados de Saúde , África/epidemiologia , Serviços de Saúde da Criança/economia , Serviços de Saúde da Criança/normas , Análise Custo-Benefício , Feminino , Infecções por HIV/diagnóstico , Infecções por HIV/economia , Humanos , Lactente , Recém-Nascido , Masculino , Testes Imediatos/economia , Testes Imediatos/normas
6.
Epidemiol Infect ; 147: e283, 2019 10 07.
Artigo em Inglês | MEDLINE | ID: mdl-31587676

RESUMO

To better understand hepatitis C virus (HCV) epidemiology in Punjab state, India, we estimated the distribution of HCV antibody positivity (anti-HCV+) using a 2013-2014 HCV household seroprevalence survey. Household anti-HCV+ clustering was investigated (a) by individual-level multivariable logistic regression, and (b) comparing the observed frequency of households with multiple anti-HCV+ persons against the expected, simulated frequency assuming anti-HCV+ persons are randomly distributed. Village/ward-level clustering was investigated similarly. We estimated household-level associations between exposures and the number of anti-HCV+ members in a household (N = 1593 households) using multivariable ordered logistic regression. Anti-HCV+ prevalence was 3.6% (95% confidence interval 3.0-4.2%). Individual-level regression (N = 5543 participants) found an odds ratio of 3.19 (2.25-4.50) for someone being anti-HCV+ if another household member was anti-HCV+. Thirty households surveyed had ⩾2 anti-HCV+ members, whereas 0/1000 (P < 0.001) simulations had ⩾30 such households. Excess village-level clustering was evident: 10 villages had ⩾6 anti-HCV+ members, occurring in 31/1000 simulations (P = 0.031). The household-level model indicated the number of household members, living in southern Punjab, lower socio-economic score, and a higher proportion having ever used opium/bhuki were associated with a household's number of anti-HCV+ members. Anti-HCV+ clusters within households and villages in Punjab, India. These data should be used to inform screening efforts.


Assuntos
Características da Família , Anticorpos Anti-Hepatite C/sangue , Hepatite C/epidemiologia , Adulto , Análise por Conglomerados , Feminino , Humanos , Índia/epidemiologia , Masculino , Pessoa de Meia-Idade , População Rural , Estudos Soroepidemiológicos , População Urbana , Adulto Jovem
7.
PLoS One ; 13(7): e0200461, 2018.
Artigo em Inglês | MEDLINE | ID: mdl-30048454

RESUMO

INTRODUCTION: Hepatitis C virus (HCV) infection prevalence is believed to be elevated in Punjab, India; however, state-wide prevalence data are not available. An understanding of HCV prevalence, risk factors and genotype distribution can be used to plan control measures in Punjab. METHODS: A cross-sectional, state-wide, population-based serosurvey using a multi-stage stratified cluster sampling design was conducted October 2013 to April 2014. Children aged ≥5 years and adults were eligible to participate. Demographic and risk behavior data were collected, and serologic specimens were obtained and tested for anti-HCV antibody, HCV Ribonucleic acid (RNA) on anti-HCV positive samples, and HCV genotype. Prevalence estimates and adjusted odds ratios for risk factors were calculated from weighted data and stratified by urban/rural residence. RESULTS: 5,543 individuals participated in the study with an overall weighted anti-HCV prevalence of 3.6% (95% Confidence Interval [CI]: 3.0%-4.2%) and chronic infection (HCV Ribonucleic acid test positive) of 2.6% (95% CI: 2.0%-3.1%). Anti-HCV was associated with being male (adjusted odds ratio 1.52; 95% CI: 1.08-2.14), living in a rural area (adjusted odds ratio 2.53; 95% CI: 1.62-3.95) and was most strongly associated with those aged 40-49 (adjusted odds ratio 40-49 vs. 19-29-year-olds 3.41; 95% CI: 1.90-6.11). Anti-HCV prevalence increased with each blood transfusion received (adjusted odds ratio 1.36; 95% CI: 1.10-1.68) and decreased with increasing education, (adjusted odds ratio 0.37 for graduate-level vs. primary school/no education; 95% CI: 0.16-0.82). Genotype 3 (58%) was most common among infected individuals. DISCUSSION: The study findings, including the overall prevalence of chronic HCV infection, associated risk factors and demographic characteristics, and genotype distribution can guide prevention and control efforts, including treatment provision. In addition to high-risk populations, efforts targeting rural areas and adults aged ≥40 would be the most effective for identifying infected individuals.


Assuntos
Hepatite C/epidemiologia , Adolescente , Adulto , Criança , Pré-Escolar , Estudos Transversais , Feminino , Geografia Médica , Hepacivirus/genética , Hepatite C/sangue , Anticorpos Anti-Hepatite C/sangue , Humanos , Índia , Masculino , Pessoa de Meia-Idade , Prevalência , Fatores de Risco , Estudos Soroepidemiológicos , Adulto Jovem
9.
J Viral Hepat ; 23(8): 631-43, 2016 08.
Artigo em Inglês | MEDLINE | ID: mdl-27025238

RESUMO

New direct-acting antivirals have the potential to transform the hepatitis C (HCV) treatment landscape, with rates of sustained viral response in excess of 90%. As these new agents are expensive, an important question is whether to focus on minimizing the consequences of severe liver disease, or reducing transmission via 'treatment as prevention'. A back-calculation model was used to estimate the impact of treatment of mild, moderate and compensated cirrhosis on incident cases of HCV-related end-stage liver disease/hepatocellular carcinoma (ESLD/HCC). In addition, a dynamic model was used to determine the impact on incidence and prevalence of chronic infection in people who inject drugs (PWID), the main risk group in England. Treating 3500 cirrhotics per year was predicted to reduce ESLD/HCC incidence from 1100 (95% CrI 970-1240) cases per year in 2015 to 630 (95% CrI 530-770) in 2020, around half that currently expected, although treating moderate-stage disease will also be needed to sustain this reduction. Treating mild-stage PWID was required to make a substantial impact on transmission: with 2500 treated per year, chronic prevalence/annual incidence in PWID was reduced from 34%/4.8% in 2015 to 11%/1.4% in 2030. There was little overlap between the two goals: treating mild stage had virtually no impact on ESLD/HCC within 15 years, but the long timescale of liver disease means relatively few PWID reach cirrhosis before cessation of injecting. Strategies focussing on treating advanced disease have the potential for dramatic reductions in severe morbidity, but virtually no preventative impact.


Assuntos
Antivirais/uso terapêutico , Quimioprevenção/métodos , Transmissão de Doença Infecciosa/prevenção & controle , Hepatite C Crônica/tratamento farmacológico , Hepatite C Crônica/prevenção & controle , Inglaterra , Hepatite C Crônica/transmissão , Humanos , Incidência , Modelos Estatísticos , Prevalência , Resultado do Tratamento
10.
J R Stat Soc Ser C Appl Stat ; 65(2): 237-257, 2016 02.
Artigo em Inglês | MEDLINE | ID: mdl-26877553

RESUMO

Evaluation of large-scale intervention programmes against human immunodeficiency virus (HIV) is becoming increasingly important, but impact estimates frequently hinge on knowledge of changes in behaviour such as the frequency of condom use over time, or other self-reported behaviour changes, for which we generally have limited or potentially biased data. We employ a Bayesian inference methodology that incorporates an HIV transmission dynamics model to estimate condom use time trends from HIV prevalence data. Estimation is implemented via particle Markov chain Monte Carlo methods, applied for the first time in this context. The preliminary choice of the formulation for the time varying parameter reflecting the proportion of condom use is critical in the context studied, because of the very limited amount of condom use and HIV data available. We consider various novel formulations to explore the trajectory of condom use over time, based on diffusion-driven trajectories and smooth sigmoid curves. Numerical simulations indicate that informative results can be obtained regarding the amplitude of the increase in condom use during an intervention, with good levels of sensitivity and specificity performance in effectively detecting changes. The application of this method to a real life problem demonstrates how it can help in evaluating HIV interventions based on a small number of prevalence estimates, and it opens the way to similar applications in different contexts.

11.
J Viral Hepat ; 22(4): 399-408, 2015 Apr.
Artigo em Inglês | MEDLINE | ID: mdl-25288193

RESUMO

Hepatitis C virus (HCV) antiviral treatment for people who inject drugs (PWID) could prevent onwards transmission and reduce chronic prevalence. We assessed current PWID treatment rates in seven UK settings and projected the potential impact of current and scaled-up treatment on HCV chronic prevalence. Data on number of PWID treated and sustained viral response rates (SVR) were collected from seven UK settings: Bristol (37-48% HCV chronic prevalence among PWID), East London (37-48%), Manchester (48-56%), Nottingham (37-44%), Plymouth (30-37%), Dundee (20-27%) and North Wales (27-33%). A model of HCV transmission among PWID projected the 10-year impact of (i) current treatment rates and SVR (ii) scale-up with interferon-free direct acting antivirals (IFN-free DAAs) with 90% SVR. Treatment rates varied from <5 to over 25 per 1000 PWID. Pooled intention-to-treat SVR for PWID were 45% genotypes 1/4 [95%CI 33-57%] and 61% genotypes 2/3 [95%CI 47-76%]. Projections of chronic HCV prevalence among PWID after 10 years of current levels of treatment overlapped substantially with current HCV prevalence estimates. Scaling-up treatment to 26/1000 PWID annually (achieved already in two sites) with IFN-free DAAs could achieve an observable absolute reduction in HCV chronic prevalence of at least 15% among PWID in all sites and greater than a halving in chronic HCV in Plymouth, Dundee and North Wales within a decade. Current treatment rates among PWID are unlikely to achieve observable reductions in HCV chronic prevalence over the next 10 years. Achievable scale-up, however, could lead to substantial reductions in HCV chronic prevalence.


Assuntos
Antivirais/uso terapêutico , Hepacivirus/isolamento & purificação , Hepatite C/tratamento farmacológico , Abuso de Substâncias por Via Intravenosa/complicações , Carga Viral , Hepatite C/epidemiologia , Hepatite C/transmissão , Humanos , Modelos Estatísticos , Resultado do Tratamento , Reino Unido/epidemiologia
13.
J Theor Biol ; 355: 140-50, 2014 Aug 21.
Artigo em Inglês | MEDLINE | ID: mdl-24727187

RESUMO

In India, the identity of men who have sex with men (MSM) is closely related to the role taken in anal sex (insertive, receptive or both), but little is known about sexual mixing between identity groups. Both role segregation (taking only the insertive or receptive role) and the extent of assortative (within-group) mixing are known to affect HIV epidemic size in other settings and populations. This study explores how different possible mixing scenarios, consistent with behavioural data collected in Bangalore, south India, affect both the HIV epidemic, and the impact of a targeted intervention. Deterministic models describing HIV transmission between three MSM identity groups (mostly insertive Panthis/Bisexuals, mostly receptive Kothis/Hijras and versatile Double Deckers), were parameterised with behavioural data from Bangalore. We extended previous models of MSM role segregation to allow each of the identity groups to have both insertive and receptive acts, in differing ratios, in line with field data. The models were used to explore four different mixing scenarios ranging from assortative (maximising within-group mixing) to disassortative (minimising within-group mixing). A simple model was used to obtain insights into the relationship between the degree of within-group mixing, R0 and equilibrium HIV prevalence under different mixing scenarios. A more complex, extended version of the model was used to compare the predicted HIV prevalence trends and impact of an HIV intervention when fitted to data from Bangalore. With the simple model, mixing scenarios with increased amounts of assortative (within-group) mixing tended to give rise to a higher R0 and increased the likelihood that an epidemic would occur. When the complex model was fit to HIV prevalence data, large differences in the level of assortative mixing were seen between the fits identified using different mixing scenarios, but little difference was projected in future HIV prevalence trends. An oral pre-exposure prophylaxis (PrEP) intervention was modelled, targeted at the different identity groups. For intervention strategies targeting the receptive or receptive and versatile MSM together, the overall impact was very similar for different mixing patterns. However, for PrEP scenarios targeting insertive or versatile MSM alone, the overall impact varied considerably for different mixing scenarios; more impact was achieved with greater levels of disassortative mixing.


Assuntos
Infecções por HIV/epidemiologia , Infecções por HIV/transmissão , HIV-1 , Homossexualidade Masculina , Modelos Biológicos , Humanos , Índia/epidemiologia , Masculino , Prevalência
14.
J Viral Hepat ; 21(9): 616-23, 2014.
Artigo em Inglês | MEDLINE | ID: mdl-24215210

RESUMO

Hepatitis C (HCV) infection can cause cirrhosis, liver cancer and death in the absence of treatment. Many people living in the UK but born overseas are believed to be infected with HCV although many are unlikely to know they are infected. The aim of this study is to assess the potential for a case-finding approach to be cost-effective and to estimate the value of further research. An economic evaluation and value of information analysis was undertaken by developing a model of HCV disease progression and by populating it with evidence from the published literature. They were performed from a UK National Health Services cost perspective, and outcomes were expressed in terms of quality-adjusted life-years (QALYs). The comparator intervention was defined as the background rate of testing (i.e. no intervention). The base case results generated an incremental cost-effectiveness ratio (ICER) of about £23,200 per additional QALY. However, the ICER was shown to be particularly sensitive to HCV seroprevalence, the intervention effect / cost and the probability of treatment uptake. The value of information analysis suggested that approximately £4 million should be spent on further research. This evaluation demonstrates that testing UK migrants for HCV could be cost-effective. However, further research, particularly to refine estimates of the probability of treatment uptake once identified, the utility associated with sustained virological response and the cost of the intervention, would help to increase the robustness of this conclusion.


Assuntos
Técnicas de Laboratório Clínico/economia , Emigrantes e Imigrantes , Hepatite C/diagnóstico , Técnicas de Laboratório Clínico/métodos , Análise Custo-Benefício , Humanos , Reino Unido
15.
AIDS Behav ; 17(2): 649-61, 2013 Feb.
Artigo em Inglês | MEDLINE | ID: mdl-22886176

RESUMO

Quantifying sexual activity of sub-populations with high-risk sexual behaviour is important in understanding HIV epidemiology. This study examined inconsistency of seven outcomes measuring self-reported clients per month (CPM) of female sex workers (FSWs) in southern India and implications for individual/population-level analysis. Multivariate negative binomial regression was used to compare key social/environmental factors associated with each outcome. A transmission dynamics model was used to assess the impact of differences between outcomes on population-level FSW/client HIV prevalence. Outcomes based on 'clients per last working day' produced lower estimates than those based on 'clients per typical day'. Although the outcomes were strongly correlated, their averages differed by approximately two-fold (range 39.0-79.1 CPM). The CPM measure chosen did not greatly influence standard epidemiological 'risk factor' analysis. Differences across outcomes influenced HIV prevalence predictions. Due to this uncertainty, we recommend basing population-based estimates on the range of outcomes, particularly when assessing the impact of interventions.


Assuntos
Preservativos/estatística & dados numéricos , Infecções por HIV/prevenção & controle , Autorrelato , Profissionais do Sexo/estatística & dados numéricos , Comportamento Sexual/estatística & dados numéricos , Parceiros Sexuais , Adulto , Algoritmos , Viés , Estudos Transversais , Feminino , Infecções por HIV/epidemiologia , Conhecimentos, Atitudes e Prática em Saúde , Humanos , Índia/epidemiologia , Aceitação pelo Paciente de Cuidados de Saúde/estatística & dados numéricos , Prevalência , Reprodutibilidade dos Testes , Estudos Retrospectivos
16.
Int J Drug Policy ; 24(1): 8-14, 2013 Jan.
Artigo em Inglês | MEDLINE | ID: mdl-23206493

RESUMO

Studies published by Zule and colleagues have suggested that use of low dead-space syringes (LDSS) instead of high dead-space syringes (HDSS) by injecting drug users (IDUs) could dramatically reduce HIV transmission. However, evidence is limited because experiments have considered a small range of syringe types and have been unable to reliably estimate the efficacy of using LDSS for reducing HIV transmission. We critically appraise available evidence to determine whether using LDSS is likely to dramatically reduce HIV transmission. We systematically review the literature on the dead-space volume of syringes and estimate the factor difference in blood volume transferred from sharing LDSS or HDSS. Existing data on the relationship between host viral load and HIV transmission risk is used to evaluate the likely efficacy of using LDSS instead of HDSS. An HIV transmission model is used to make conservative impact projections for switching to using LDSS, and explore the implications of heterogeneity in IDU transmission risk and syringe preferences. Although highly variable, reviewed studies suggest that HDSS have on average 10 times the dead-space volume of LDSS and could result in 6/54/489 times more blood being transferred after 0/1/2 water rinses. Assuming a conservative 2-fold increase in HIV transmission risk per 10-fold increase in infected blood inoculum, HDSS use could be associated with a mean 1.7/3.6/6.5-fold increase in transmission risk compared to LDSS for 0/1/2 rinses. However, even for a low efficacy estimate, modelling suggests that partially transferring to LDSS use from using HDSS could dramatically reduce HIV prevalence (generally >33% if LDSS use is 50%), but impact will depend on IDU behavioural heterogeneity and syringe preference. Indirect evidence suggests that encouraging HDSS users to use LDSS could be a powerful HIV prevention strategy. There is an urgent need to evaluate the real life effectiveness of this strategy.


Assuntos
Usuários de Drogas , Epidemias/prevenção & controle , Infecções por HIV/prevenção & controle , Programas de Troca de Agulhas , Abuso de Substâncias por Via Intravenosa/epidemiologia , Seringas , Animais , Humanos
17.
Drug Alcohol Depend ; 126(3): 324-32, 2012 Dec 01.
Artigo em Inglês | MEDLINE | ID: mdl-22728045

RESUMO

BACKGROUND: A 2006 respondent driven sampling (RDS) survey of injecting drug users (IDUs) in Bristol, UK, estimated 40 per 100 person years HCV incidence but in 2009 another RDS survey estimated only 10 per 100 person years incidence amongst the same population. Estimated increases in intervention exposure do not fully explain the decrease in risk. We investigate whether the underlying contact network structure and differences in the structure of the RDS trees could have contributed to the apparent change in incidence. METHOD: We analyse the samples for evidence that individuals recruit participants who are like themselves (assortative recruiting). Using an assortativity measure, we develop a Monte Carlo approach to determine whether the RDS data exhibit significantly more assortativity than is expected for that sample. Motivated by these findings, a network model is used to investigate how much assortativity and the structure of the RDS tree impacts sample estimates of prevalence and incidence. RESULTS: The samples suggest there is some assortativity on injecting habits or markers of injecting risk. The 2009 sample has lower assortativity than 2006. Simulations of RDS confirm that assortativity influences the estimated incidence in a population and the structure of RDS samples can result in bias. Our simulations suggest that RDS incidence estimates have considerable variance, making them difficult to use for monitoring trends. CONCLUSIONS: We suggest there was likely to have been a decline in risk between 2006 and 2009 due to increased intervention coverage, but the bias and variance in the estimates prevents accurate estimation of the incidence.


Assuntos
Abuso de Substâncias por Via Intravenosa/epidemiologia , Adulto , Viés , Feminino , Hepatite C/epidemiologia , Hepatite C/etiologia , Humanos , Incidência , Masculino , Método de Monte Carlo , Prevalência , Estudos de Amostragem , Abuso de Substâncias por Via Intravenosa/complicações , Reino Unido/epidemiologia
18.
Sex Transm Infect ; 86 Suppl 1: i89-94, 2010 Feb.
Artigo em Inglês | MEDLINE | ID: mdl-20167740

RESUMO

BACKGROUND: The India AIDS Initiative (Avahan) project is involved in rapid scale-up of HIV-prevention interventions in high-risk populations. This study examines the cost variation of 107 non-governmental organisations (NGOs) implementing targeted interventions, over the start up (defined as period from project inception until services to the key population commenced) and first 2 years of intervention. METHODS: The Avahan interventions for female and male sex workers and their clients, in 62 districts of four southern states were costed for the financial years 2004/2005 and 2005/2006 using standard costing techniques. Data sources include financial and economic costs from the lead implementing partners (LPs) and subcontracted local implementing NGOs retrospectively and prospectively collected from a provider perspective. Ingredients and step-down allocation processes were used. Outcomes were measured using routinely collected project data. The average costs were estimated and a regression analysis carried out to explore causes of cost variation. Costs were calculated in US$ 2006. RESULTS: The total number of registered people was 134,391 at the end of 2 years, and 124,669 had used STI services during that period. The median average cost of Avahan programme for this period was $76 per person registered with the project. Sixty-one per cent of the cost variation could be explained by scale (positive association), number of NGOs per district (negative), number of LPs in the state (negative) and project maturity (positive) (p<0.0001). CONCLUSIONS: During rapid scale-up in the initial phase of the Avahan programme, a significant reduction in average costs was observed. As full scale-up had not yet been achieved, the average cost at scale is yet to be realised and the extent of the impact of scale on costs yet to be captured. Scale effects are important to quantify for planning resource requirements of large-scale interventions. The average cost after 2 years is within the range of global scale-up costs estimates and other studies in India.


Assuntos
Custos de Cuidados de Saúde/estatística & dados numéricos , Homossexualidade Masculina , Trabalho Sexual , Infecções Sexualmente Transmissíveis/prevenção & controle , Transexualidade , Instituições de Assistência Ambulatorial/economia , Instituições de Assistência Ambulatorial/organização & administração , Serviços de Saúde Comunitária/economia , Serviços de Saúde Comunitária/organização & administração , Feminino , Promoção da Saúde/economia , Promoção da Saúde/organização & administração , Humanos , Índia , Masculino , Organizações/economia , Infecções Sexualmente Transmissíveis/complicações , Infecções Sexualmente Transmissíveis/economia , Infecções Sexualmente Transmissíveis/transmissão , Abuso de Substâncias por Via Intravenosa/complicações
19.
Eur J Public Health ; 19(4): 428-33, 2009 Aug.
Artigo em Inglês | MEDLINE | ID: mdl-19349288

RESUMO

BACKGROUND: The aim of the study was to measure risk of HIV and HCV infection among injecting drug users (IDUs) through force of infection (FOI) models in three cities of the Russian Federation and assess the value of behavioural data and FOI in predicting risk of infection as a method of second-generation surveillance. METHODS: FOI models were fitted to prevalence data collected through an anonymous, cross-sectional community-recruited survey of IDUs with oral fluid sample collection for antibodies to HIV and HCV. Risk of infection was estimated from FOI estimates obtained by fitting a model to prevalence data by length of injecting career for each city and then overall. Risk behaviours were examined by injecting career length. RESULTS: A total of 1473 IDUs were recruited. Prevalence of HIV was 8.1% (95% CI 6.7-9.6%) and HCV 63.4% (95% CI 60.9-65.9%). A higher FOI in new initiates to injecting (injecting career length <1 year) was found for both HIV and HCV compared with experienced IDUs (injecting career length <5 years). Increased risk of infection was not corroborated by injecting risk behaviours among new initiates into injecting (n = 38). Only 5.7% (n = 2) reported receptive sharing in the last 4 weeks, 57.9% (n = 22) sharing any injecting paraphernalia, 2.6% (n = 1) frontloading and 8.5% (n = 3) ever injecting with used needles/syringes. However, 29% of new initiates reported exchanging sex in the last 4 weeks (29%) compared with 11% long term IDUs. CONCLUSIONS: FOI models can play an important role in surveillance of HIV but caution is needed in the interpretation of behavioural data for predicting current or future risk of HIV.


Assuntos
Infecções por HIV/etiologia , Hepatite C/etiologia , Abuso de Substâncias por Via Intravenosa/complicações , Adolescente , Adulto , Estudos Transversais , Feminino , Infecções por HIV/epidemiologia , Hepacivirus/patogenicidade , Hepatite C/epidemiologia , Humanos , Masculino , Modelos Teóricos , Vigilância da População , Medição de Risco , Federação Russa/epidemiologia , Treponema pallidum/isolamento & purificação , Adulto Jovem
20.
Sex Transm Infect ; 85 Suppl 2: ii17-22, 2009 Apr.
Artigo em Inglês | MEDLINE | ID: mdl-19307346

RESUMO

OBJECTIVES: To measure the prevalence of hepatitis C virus (HCV), HIV and sexually transmitted infections (STI) among injecting drug users (IDUs) in Rawalpindi and Abbottabad and to examine risk factors associated with HIV and HCV. METHODS: Two cross-sectional surveys were performed of community-recruited IDUs with collection of clinical specimens for testing of HCV, HIV and other STIs. Behavioural data were collected through interviewer-administered questionnaires. Characteristics and risk behaviours were compared across cities. Univariate and multivariate analyses explored risk factors associated with HIV and HCV. RESULTS: The prevalence of HIV was 2.6% (95% CI 0.83% to 4.5%) in Rawalpindi (n = 302) and zero in Abbottabad (n = 102). The prevalence of HCV was significantly higher in Rawalpindi at 17.3% (95% CI 13.0% to 21.6%) than in Abbottabad at 8% (95% CI 2.6% to 13.4%). The prevalence of other STIs was low in both cities, with <2% of participants having current gonorrhoea or Chlamydia and <3% with active syphilis. Injecting risk behaviours were greater in Rawalpindi. An increased risk of HCV was associated with using informal sources as a main source of new needles/syringes (OR 2.8, 95% CI 1.3 to 6.0) compared with pharmacies and a history of drug treatment (OR 3.7, 95% CI 0.9 to 11.6). Reporting symptoms of an STI was associated with decreased odds of HIV in Rawalpindi (OR 0.02, 95% CI 0.03 to 0.9). CONCLUSIONS: The findings suggest recent transmission of HIV and HCV and point to the urgent need for the provision of clean needles/syringes to IDUs and a review of how needles/syringes are currently provided via healthcare establishments.


Assuntos
Hepatite C Crônica/epidemiologia , Infecções Sexualmente Transmissíveis/epidemiologia , Abuso de Substâncias por Via Intravenosa/epidemiologia , Adulto , Estudos Transversais , Surtos de Doenças , Feminino , Infecções por HIV/epidemiologia , Humanos , Masculino , Paquistão/epidemiologia , Prevalência , Fatores de Risco , Sexo sem Proteção/estatística & dados numéricos
SELEÇÃO DE REFERÊNCIAS
DETALHE DA PESQUISA
...