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Matthew Hickman

Publications and source records attributed to Matthew Hickman.

30 records · Page 2Linked to original sources
PubMed2004

Estimating long-term trends in the incidence and prevalence of opiate use/injecting drug use and the number of former users: back-calculation methods and opiate overdose deaths.

The authors explored an age-specific back-calculation approach to estimating long-term trends in the incidence and prevalence of opiate use/injecting drug use (IDU) in England for 1968-2000. The incidence of opiate use/IDU was estimated by combining information on the observed opiate overdose deaths of persons aged 15-44 years with knowledge on the distribution of the time between starting opiate use/IDU and death by overdose (incubation time distribution). The resulting incidence, together with the incubation time distribution, other drug-related mortality, and the general age-specific mortality rate, was then used to estimate the prevalence of current and former users. Provisional estimates suggested two major increases in incidence in the late 1970s and early 1990s, with models including information on age at death suggesting a recent decline since 1997 and that prevalence of opiate use/IDU increased substantially in the 1990s. Results were crucially dependent on assumptions about key parameters of the back-calculation framework. In theory, the approach is a valuable addition to the portfolio of indirect methods for estimating incidence and prevalence of dependent opiate use/IDU. In practice, its full potential will be realized only once better information on the process of stopping opiate use/IDU becomes available and more precise estimates of current and historical overdose mortality are obtained.

Adolescent↗
PubMed2004

The prevalence of injecting drug use in a Russian city: implications for harm reduction and coverage.

AIM: This study sought to estimate the prevalence of injecting drug users (IDU) in Togliatti city and to examine the implications of these estimates for HIV prevalence and harm reduction. DESIGN: Routine data sources of IDUs were identified. Covariate capture-recapture techniques were used on the individuals identified on the three data sources and used to estimate the number of IDU 'not observed' by the data sources, and thereby estimate the prevalence of IDU. SETTING: Togliatti City, Samara Oblast, Russian Federation. PARTICIPANTS: IDUs recorded on three data sources (narcology records, HIV positive test results and police arrest data) during 2001. MEASUREMENTS: Poisson regression models were fitted to the observed data, with interactions between data sources fitted to replicate 'dependencies' between those data sources. To select the best model the goodness of fit was approximated by chi2 distribution and the best-fitting model was selected on the basis of standard information criteria and log likelihood ratio tests. FINDINGS: The total estimated population of IDUs is 20 226 [95% confidence interval (CI): 16 971-24 749] giving a population prevalence of 5.4% (95% CI: 4.5-6.6%) of the registered population and 2.7% (95% CI: 2.4-3.5%) of the population (including migrants) aged 15-44 years. For every one IDU in contact with a service there were three out of contact. CONCLUSIONS: There is a high prevalence of IDU which, in the context of a fast-emerging IDU-associated HIV epidemic, will have serious public health implications.

Adolescent↗
PubMed2004

Injecting drug use in Brighton, Liverpool, and London: best estimates of prevalence and coverage of public health indicators.

STUDY OBJECTIVE: To estimate the prevalence of injecting drug use (IDU) in three cities in England and to measure the coverage of key public health indicators. DESIGN: Capture-recapture techniques with covariate effects. SETTING: Liverpool, Brighton, and 12 London boroughs, 2000/01. PARTICIPANTS: IDU collated and matched across five data sources-community recruited survey, specialist drug treatment, arrest referral, syringe exchange, and accident and emergency-896 in Brighton, 1224 in Liverpool, and 6111 in London. MAIN RESULTS: It is estimated that in 2000/01 the number and prevalence of IDU aged 15-44 was 2300 (95%CI 1500 to 3700) and 2.0% (95%CI% 1.3% to 3.2%) in Brighton; 2900 (95%CI 2500 to 5000) and 1.5% (95%CI 1.3% to 2.6%) in Liverpool; 16 700 (95%CI 13 800 to 21 600) and 1.2% (95%CI 1.0% to 1.6%) in 12 London boroughs; with a prevalence of 1.7% (95%CI 1.2% to 3.3%) in inner London. It is estimated that: less than one in four IDU are in treatment in the three areas; syringe exchange programmes covered about 25% of injections in Brighton and Liverpool and 20% in London; and that the annual opioid mortality rate among IDU was 2% in Brighton compared with less than 1% in Liverpool and London. CONCLUSIONS: Credible estimates of the prevalence of injecting drug use (and key public health indicators) can be determined using covariate capture-recapture techniques. These suggest that: targets to double the number in treatment are possible: syringe distribution should be increased; and further attention, especially in Brighton, given to reducing overdose mortality.

Adolescent↗
PubMed2003

Evaluation of a modified commercial assay in detecting antibody to hepatitis C virus in oral fluids and dried blood spots.

Oral fluid testing is an effective alternative to serum antibody testing for surveillance of human immunodeficiency virus (HIV) and hepatitis B infections, and is being extended to hepatitis C infections. The objective of this study was to determine and compare the sensitivity and specificity of a modified commercial assay for the detection of antibody to hepatitis C virus (anti-HCV) in oral fluids collected by two different oral fluid collection devices (the Epitope OraSure trade mark and Sarstedt Salivette ) and in dried fingerprick blood spots. In this study, 253 anti-HCV seropositive patients and 394 blood donors (all anti-HCV negative) were recruited between August 2000 and January 2001. Each participant provided oral fluid specimens by OraSure and Salivette, and at least one dried blood spot. Serum specimens were collected from the patients whenever possible. For those injecting drug users who did not provide a serum specimen, HCV status was established on the basis of previous testing. All the nonserum samples were tested for the presence of anti-HCV, using a modified Ortho HCV 3.0 SAVe enzyme-linked immunosorbent assay (ELISA) protocol. The recommended preliminary cutoffs for the modified ELISA were suboptimal. Further, the sensitivity, specificity, and positive and negative predictive values could be improved by varying the cutoff and taking into account the likely prevalence of HCV in the population under investigation. For instance, given a population with a 50% prevalence of anti-HCV, the optimal sensitivities of the modified assay on OraSure, Salivette, and dried blood spots were 92%, 83%, and virtually 100%, respectively, in contrast to 83%, 59%, and 99% using the preliminary cutoffs. The respective optimal specificities were 99%, 93%, and 100%. In conclusion, oral fluids collected by the OraSure device provide an extremely useful method to conduct public health surveillance of not only HIV, but also hepatitis C, among injecting drug users. In addition, dried blood spot specimens may be useful for surveillance and could be employed as a first line diagnostic specimen.

Blood Specimen Collection↗
PubMed2003

Trends in drug overdose deaths in England and Wales 1993-98: methadone does not kill more people than heroin.

AIMS: To test the hypothesis that methadone is responsible for a greater increase in overdose deaths than heroin, and causes proportionally more overdose deaths than heroin at weekends. DESIGN AND SETTING: Multivariate analysis of 3961 death certificates mentioning heroin, morphine and/or methadone held on the Office for National Statistics drug-related poisoning mortality database from 1993 to 1998 in England and Wales. MEASUREMENTS: Percentage increase in deaths by year by drug, odds ratio (OR) of dying at the weekend from methadone-related overdose compared to dying from heroin/morphine overdose. FINDINGS: From 1993 to 1998, annual opiate overdose deaths increased from 378 to 909. There was a 24.7% (95% confidence interval (CI) 22-28%) yearly increase in heroin deaths compared to 9.4% (95% CI 6-13%) for methadone only. This difference was significant (P < 0.001 by test of interaction) after adjustment for sex, age group, polydrug use, area of residence and underlying cause of death. The largest number of deaths occurred on Saturday (673). The OR of death from methadone overdose on Saturday and Sunday was 1.48 (95% CI 1.29-1.71) for methadone-only deaths compared to dying from heroin/morphine at the weekend after adjustment for other covariates, but the OR was not significant (1.09, 95% CI 0.95-1.25) if the weekend was defined as Friday and Saturday. CONCLUSIONS: There was no evidence that the threefold increase in deaths over time was due to methadone. There was equivocal support only for the hypothesis that there was an excess of deaths from methadone at weekends. Increased interventions to prevent overdose among injectors in England and Wales are long overdue.

Adolescent↗
PubMed2003

Drug-related mortality and fatal overdose risk: pilot cohort study of heroin users recruited from specialist drug treatment sites in London.

Fatal overdose and drug-related mortality are key harms associated with heroin use, especially injecting drug use (IDU), and are a significant contribution to premature mortality among young adults. Routine mortality statistics tend to underreport the number of overdose deaths and do not reflect the wider causes of death associated with heroin use. Cohort studies could provide evidence for interpreting trends in routine mortality statistics and monitoring the effectiveness of strategies that aim to reduce drug-related deaths. We aimed to conduct a retrospective mortality cohort study of heroin users recruited from an anonymous reporting system from specialist drug clinics. Our focus was to test whether (1). specialist agencies would agree to participate with a mortality cohort study, (2). a sample could be recruited to achieve credible estimates of the mortality rate, and (3). ethical considerations could be met. In total, 881 heroin users were recruited from 15 specialist drug agencies. The overall mortality rate of the cohort of heroin users was 1.6 (95% confidence interval [CI], 1.1 to 2.2) per 100 person-years. Mortality was higher among males, heroin users older than 30 years, and injectors, but not significantly higher after adjustment in a Cox proportional hazard model. Among the 33 deaths, 17 (52%) were certified from a heroin/methadone or opiate overdose, 4 (12%) from drug misuse, 4 (12%) unascertained, and 8 (24%) unrelated to acute toxic effects of drug use. Overall, the overdose mortality rate was estimated to be at least 1.0 per 100 person-years. The standardized mortality ratio (SMR) was 17 times higher for female and male heroin users in the cohort compared to mortality in the non-heroin-using London population aged 15-59 years. The pilot study showed that these studies are feasible and ethical, and that specialist drug agencies could have a vital role to play in the monitoring of drug-related mortality.

Adult↗
PubMed2002

Explosive spread and high prevalence of HIV infection among injecting drug users in Togliatti City, Russia.

OBJECTIVE: To establish the prevalence of antibodies to HIV (anti-HIV) and associated risk factors among injecting drug users (IDU) in Togliatti City, Samara Oblast, Russian Federation. DESIGN: An unlinked anonymous cross-sectional community recruited survey with oral fluid sample collection. METHODS: Between September and October 2001, 426 IDU were recruited by trained fieldworkers. Participants completed an interviewer administered questionnaire, and oral fluid samples were tested for anti-HIV. Univariate and multivariate analyses compared potential risk factors for anti-HIV. RESULTS: Anti-HIV prevalence was 56% (234/418). Three-quarters of anti-HIV-positive IDU (74%) were unaware of their positive status. In an adjusted model, the odds of HIV infection were higher among IDU who had ever injected home-produced drugs, who reported injecting with used needles and syringes in the past 4 weeks, and who were living in one particular district of the city (Komsomolksii). CONCLUSION: The high prevalence of HIV, and a recent increase in HIV detected through routine screening tests since 2000, suggests that an explosive epidemic has occurred among IDU in Togliatti City. In the face of currently inadequate HIV prevention coverage among IDU, this has urgent implications for maximizing the distribution of sterile injecting equipment as well as for enhancing sexual risk reduction. Recognizing that it is likely that similar explosive epidemics are taking place in other Russian cities, we recommend community-wide HIV prevention coverage supported by city and state policies oriented to harm reduction.

AIDS Serodiagnosis↗
PubMed2002

Over a decade of syringe exchange: results from 1997 UK survey.

AIMS: To describe syringe exchange provision in the United Kingdom. DESIGN: Two-phase cross-sectional survey: phase I, establishing a sampling frame of syringe exchange coordinators (n=420); phase II, surveying the coordinators seeking data on the number of syringe exchange outlets, visits and syringes distributed during April 1997 (68% response rate). SETTING: United Kingdom. FINDINGS: In 1997, nearly all Health Authorities in the United Kingdom (96%) operated some form of syringe exchange service, except Northern Ireland. In April 1997, 1 707 000 syringes were reported as being distributed. Assuming that non-responders coordinated the median number of outlets and distributed the median number of syringes as responders, we estimate that 27 million syringes were distributed annually from over 2000 outlets in the United Kingdom. The number distributed in Scotland was 3-4 times less than in England when measured as a number per adult (15-44), drug user in treatment, or estimated injecting drug user. CONCLUSIONS: Overall, there has been a 6.5-fold increase in syringe distribution in England since 1991. The number of syringes distributed in the United Kingdom may be higher than the United States. However, there appears to be unequal distribution of syringes within the United Kingdom, which may be associated with higher levels of HCV among injectors in Scotland compared to England.

Adolescent↗