Increasing drug-related mortality rates over the last decade in Scotland are not just due to an ageing cohort: A retrospective longitudinal cohort study

BACKGROUND

In Europe, North America, and Australia, mortality due to drug-related (DR) causes amongst people who inject drugs (PWID) is a major issue. Our objective was to characterise temporal trends in DR mortality rates in a large cohort of PWID in Scotland over the past decade, all of whom had been diagnosed with hepatitis C virus (HCV) infection, and to investigate factors associated with DR mortality.

METHODS

Retrospective longitudinal cohort study linking Scotland's national HCV Diagnosis Database and deaths registry. The study cohort consisted of all individuals with likely injection drug use-related route of HCV acquisition, who had been diagnosed with HCV between 1991 and 2018, and were alive and aged under 65 years on 1 January 2009. We used Lexis expansion to adjust for ageing cohort effects and calculated the mortality rate from an underlying/contributing DR cause over the period 2009-2018. We fitted Poisson regression models to estimate the temporal trend adjusting for attained age, sex, referral setting, region, and viraemic status at baseline.

RESULTS

Amongst the study population (n = 35,065; 236,914 person-years), a total of 1900 DR deaths occurred; the DR mortality rate increased from 5.6/1000 [101 deaths] in 2009 to 12.4/1000 [342] person-years in 2018. Increasing trends were observed for all age-groups except 55-64 years. The overall DR mortality rate was highest for referrals for HCV testing from prison (11.0/1000) and hospital settings (10.0/1000). Mortality increased with calendar time period, with significantly raised adjusted rate ratios (RRs) from 2015 (RR=1.40, 95% CI:1.16-1.69) to 2018 (RR=2.23, 95% CI:1.88-2.64), compared with 2011-2012, for older age (35-44: RR=1.37, 95% CI:1.20-1.56; 45-54: RR=1.32, CI:1.14-1.53) compared with <35 years, for persons diagnosed with HCV since 2009 (RR=1.34, 95% CI:1.21-1.49), and for prison and hospital referrals (RRs of 1.30, 1.37) compared with GP referrals.

CONCLUSION

Increasing DR mortality rates in Scotland over the past decade are not just due to an ageing cohort. Harm reduction services will likely need to expand and adapt to reverse the recent upward trends in DR mortality in PWID.

Nano- and micro-patterning biotemplated magnetic CoPt arrays

Patterned thin-films of magnetic nanoparticles (MNPs) can be used to make: surfaces for manipulating and sorting cells, sensors, 2D spin-ices and high-density data storage devices. Conventional manufacture of patterned magnetic thin-films is not environmentally friendly because it uses high temperatures (hundreds of degrees Celsius) and high vacuum, which requires expensive specialised equipment. To tackle these issues, we have taken inspiration from nature to create environmentally friendly patterns of ferromagnetic CoPt using a biotemplating peptide under mild conditions and simple apparatus. Nano-patterning via interference lithography (IL) and micro-patterning using micro-contact printing (μCP) were used to create a peptide resistant mask onto a gold surface under ambient conditions. We redesigned a biotemplating peptide (CGSGKTHEIHSPLLHK) to self-assemble onto gold surfaces, and mineralised the patterns with CoPt at 18 °C in water. Ferromagnetic CoPt is biotemplated by the immobilised peptides, and the patterned MNPs maintain stable magnetic domains. This bioinspired study offers an ecological route towards developing biotemplated magnetic thin-films for use in applications such as sensing, cell manipulation and data storage.

A novel design strategy for nanoparticles on nanopatterns: interferometric lithographic patterning of Mms6 biotemplated magnetic nanoparticles

Nanotechnology demands the synthesis of highly precise, functional materials, tailored for specific applications. One such example is bit patterned media. These high-density magnetic data-storage materials require specific and uniform magnetic nanoparticles (MNPs) to be patterned over large areas (cm² range) in exact nanoscale arrays. However, the realisation of such materials for nanotechnology applications depends upon reproducible fabrication methods that are both precise and environmentally-friendly, for cost-effective scale-up. A potentially ideal biological fabrication methodology is biomineralisation. This is the formation of inorganic minerals within organisms, and is known to be highly controlled down to the nanoscale whilst being carried out under ambient conditions. The magnetotactic bacterium Magnetospirillum magneticum AMB-1 uses a suite of dedicated biomineralisation proteins to control the formation of magnetite MNPs within their cell. One of these proteins, Mms6, has been shown to control formation of magnetite MNPs in vitro. We have previously used Mms6 on micro-contact printed (μCP) patterned self-assembled monolayer (SAM) surfaces to control the formation and location of MNPs in microscale arrays, offering a bioinspired and green-route to fabrication. However, μCP cannot produce patterns reliably with nanoscale dimensions, and most alternative nanofabrication techniques are slow and expensive. Interferometric lithography (IL) uses the interference of laser light to produce nanostructures over large areas via a simple process implemented under ambient conditions. Here we combine the bottom-up biomediated approach with a top down IL methodology to produce arrays of uniform magnetite MNPs (86 ± 21 nm) with a period of 357 nm. This shows a potentially revolutionary strategy for the production of magnetic arrays with nanoscale precision in a process with low environmental impact, which could be scaled readily to facilitate large-scale production of nanopatterned surface materials for technological applications.

The role of APOE-ɛ4 and beta amyloid in the differential rate of recovery from ECT: a review

Individual biological differences may contribute to the variability of outcomes, including cognitive effects, observed following electroconvulsive treatment (ECT). A narrative review of the research literature on carriage of the apolipoprotein E ɛ4 allele (APOE-ɛ4) and the protein biomarker beta amyloid (Aβ) with ECT cognitive outcome was undertaken. ECT induces repeated brain seizures and there is debate as to whether this causes brain injury and long-term cognitive disruption. The majority of ECT is administered to the elderly (over age 65 years) with drug-resistant depression. Depression in the elderly may be a symptom of the prodromal stage of Alzheimer's disease (AD). Carriage of the APOE-ɛ4 allele and raised cerebral Aβ are consistently implicated in AD, but inconsistently implicated in brain injury (and related syndromes) recovery rates. A paucity of brain-related recovery, genetic and biomarker research in ECT responses in the elderly was found: three studies have examined the effect of APOE-ɛ4 allele carriage on cognition in the depressed elderly receiving ECT, and two have examined Aβ changes after ECT, with contradictory findings. Cognitive changes in all studies of ECT effects were measured by a variety of psychological tests, making comparisons of such changes between studies problematic. Further, psychological test data-validity measures were not routinely administered, counter to current testing recommendations. The methodological issues of the currently available literature as well as the need for well-designed, hypothesis driven, longitudinal studies are discussed.

Uptake of hepatitis C antibody testing in patients with end-stage liver disease in Glasgow, 1993-2007

Individuals infected with hepatitis C virus (HCV) need to be diagnosed well before developing end-stage liver disease to benefit from treatment. We aimed to ascertain what proportion of cases had been tested for HCV to inform on the effectiveness of current guidelines. Record linkage between national databases of HCV tests, hospital discharges and deaths identified 10,645 persons who were hospitalized or had died with mention of end-stage liver disease in Glasgow, Scotland, between 1993 and 2007. We estimated HCV test uptake and prevalence of HCV infection within the study population. The associations between both HCV test uptake and HCV-antibody status and sex, age group and deprivation quintile were estimated using logistic regression. We found that 43% of those hospitalized (n = 9153) and 23% of those who otherwise died (n = 1492) with first-time mention of end-stage liver disease had been tested for HCV during this period. Test uptake in those hospitalized increased from 13 (95% CI: 12-14%) in 1993-1997 to 58% (56-59%) in 2003-2007. The adjusted odds of being tested for HCV were significantly higher for men (OR=1.3, 95% CI: 1.2-1.5), for ages 25-54 (25-34 years: 2.7, 95% CI: 2.1-3.4; 35-44 years: 2.3, 95% CI: 2.0-2.6; 45-54 years: 1.5, 95% CI: 1.4-1.7) compared with 55+ years, and for those residing in the two most deprived quintiles (1.1, 95% CI: 1.0-1.2). Twenty-eight per cent of the HCV testees aged 25-44 years were HCV infected. These results highlight the continuing need for raising awareness among medical professionals for comprehensive HCV testing in patients with liver disease.

The influence of hepatitis C and alcohol on liver-related morbidity and mortality in Glasgow's injecting drug user population

Infection with the hepatitis C virus (HCV) is associated with the development of severe liver disease, but cofactors--namely alcohol abuse--in Scotland's HCV-positive population complicate estimation of the unique contribution of HCV. We compared the risk of hospital admission/death for a liver-related cause in a large cohort of Glasgow's injecting drug users (IDUs) testing HCV-positive with IDUs testing HCV negative. Data for 6566 current/former IDUs who had been tested for anti-HCV and/or HCV RNA by polymerase chain reaction in Greater Glasgow health board between 1993 and 2007 were linked to the national hospitalization database and deaths registry to identify all admissions and deaths from a liver-related condition. Relative risks were estimated using Cox proportional hazards regression for recurrent events. Time at risk was censored at 2 years following an HCV test to address bias owing to unobserved seroconversion. The risk of hospitalization/death from a liver-related or an alcoholic liver-related condition following HCV testing was greater for those IDUs with no prior alcohol-related hospitalization who tested positive [adjusted hazard ratio (HR) = 3.2, 95% CI: 1.5-6.7; 4.9, 95% CI: 1.8-13.1, respectively], compared with those who tested anti-HCV negative, but not for those IDUs with a prior alcohol admission (HR = 0.8, 95% CI: 0.4-1.5; 0.8, 95% CI: 0.4-1.6). There was little evidence for an increased risk of hospitalization/death for an exclusively nonalcoholic liver condition for those testing positive (HR = 1.5, 95% CI: 0.8-2.7), after adjustment for previous alcohol-related admission. Within Glasgow's IDU population, HCV positivity is associated with an increased risk of a liver-related outcome, but this is not observed for those IDUs whose problem alcohol use already increases their risk.

The growing contribution of hepatitis C virus infection to liver-related mortality in Scotland

The large number of individuals in Scotland who became infected with the hepatitis C virus (HCV) in the 1970s and 1980s leads us to expect liver-related morbidity and mortality to increase in the coming years. We investigated the contribution of HCV to liver-related mortality in the period January 1991 to June 2006. The study population consisted of 26,861 individuals whose death record mentioned a liver-related cause (underlying or contributing). Record-linkage to the national HCV Diagnosis database supplied HCV-diagnosed status for the study population. The proportion diagnosed with HCV among people dying from a liver-related cause rose from 2.8% (1995-1997) to 4.4% (2004-June 2006); the largest increase occurred in those aged 35-44 years at death (7% to 17%). Among all deaths from a liver-related cause, an HCV-positive diagnosis was more likely in those who died in 2001 or later than those who died in 1995-1997 (2001-2003: odds ratio=1.4, 95% confidence interval: 1.1-1.7; 2004-June 2006: 1.6, 1.3-2.0), and in those who died at under 55 compared with at least 55 years of age. HCV infection represents a significant, growing, public health burden in Scotland in terms of early deaths from liver disease.

The growing contribution of hepatitis C virus infection to liver-related mortality in Scotland

The large number of individuals in Scotland who became infected with the hepatitis C virus (HCV) in the 1970s and 1980s leads us to expect liver-related morbidity and mortality to increase in the coming years. We investigated the contribution of HCV to liver-related mortality in the period January 1991 to June 2006. The study population consisted of 26,861 individuals whose death record mentioned a liver-related cause (underlying or contributing). Record-linkage to the national HCV Diagnosis database supplied HCV-diagnosed status for the study population. The proportion diagnosed with HCV among people dying from a liver-related cause rose from 2.8% (1995-1997) to 4.4% (2004-June 2006); the largest increase occurred in those aged 35-44 years at death (7% to 17%). Among all deaths from a liver-related cause, an HCV-positive diagnosis was more likely in those who died in 2001 or later than those who died in 1995-1997 (2001-2003: odds ratio (OR)=1.4, 95% confidence interval (CI): 1.1-1.7; 2004-June 2006: 1.6, 1.3-2.0), and in those who died at under 55 compared with at least 55 years of age. HCV infection represents a significant, growing, public health burden in Scotland in terms of early deaths from liver disease.

A record-linkage study of the development of hepatocellular carcinoma in persons with hepatitis C infection in Scotland

We investigated trends in first-time hospital admissions and deaths attributable to hepatocellular carcinoma (HCC) in a large population-based cohort of 22 073 individuals diagnosed with hepatitis C viral (HCV) infection through laboratory testing in Scotland in 1991–2006. We identified new cases of HCC through record-linkage to the national inpatient hospital discharge database and deaths registry. A total of 172 persons diagnosed with HCV were admitted to hospital or died with first-time mention of HCC. Hepatocellular carcinoma incidence increased between 1996 and 2006 (average annual change of 6.1, 95% confidence interval (CI): 0.9–11.6%, P=0.021). The adjusted relative risk of HCC was greater for males (hazard ratio=2.7, 95% CI: 1.7–4.2), for those aged 60 years or older (hazard ratio=2.7, 95% CI: 1.9–4.1) compared with 50–59 years, and for those with a previous alcohol-related hospital admission (hazard ratio=2.5, 95% CI: 1.7–3.7). The risk of individuals diagnosed with HCV developing HCC was greatly increased compared with the general Scottish population (standardised incidence ratio=127, 95% CI: 102–156). Owing to the advancing age of the Scottish HCV-diagnosed population, the annual number of HCC cases is projected to increase, with a consequent increasing burden on the public healthcare system.

Hepatitis C virus infection in Scotland: epidemiological review and public health challenges

INTRODUCTION

In 2004, Scotland's Health Minister stated that the hepatitis C virus (HCV) "is one of the most serious and significant public health risks of our generation".

METHODS

To appreciate the prevention and care challenges posed by HCV in Scotland, we reviewed all country-specific data on i) the prevalence of infection among different populations, ii) the numbers infected with HCV, and iii) the current and future HCV disease burden.

RESULTS

An estimated 1% of Scotland's population has HCV; 85-90% of those infected were injecting drug users (IDUs). Reductions in HCV prevalence among young IDUs during the early 1990s suggest that the incidence of HCV had decreased; since then, the absence of further reductions highlight that existing prevention measures are insufficient. Two-thirds of the estimated 37,500 chronically HCV-infected individuals in Scotland remain undiagnosed and two-thirds of this group are former IDUs. An estimated 9,000 former IDUs were living with either moderate or severe HCV disease in 2004; if the current uptake of antiviral therapy continues, this number was estimated to double by 2016. Approximately 1,200 HCV-infected IDUs had developed liver failure by 2004; this figure was predicted to increase to 3,200 by 2020.

CONCLUSIONS

Scotland faces three principal public health challenges: i) the prevention of HCV among current IDUs, ii) the diagnosis of HCV-infected persons, particularly those most in need of therapy to prevent severe HCV disease, and iii) the current and future provision of adequate resources to ensure that the movement of patients through the diagnostic and clinical care pathway is optimal.

Predicting incidence of variant Creutzfeldt-Jakob disease from UK dietary exposure to bovine spongiform encephalopathy for the 1940 to 1969 and post-1969 birth cohorts

BACKGROUND

To investigate variant Creutzfeldt-Jakob disease (vCJD) incubation period, transmission barrier, and short-term vCJD predictions for methionine homozygotes in 1940-1969 and post-1969 birth cohorts by use of gender- and age-specific exposure intensities to bovine spongiform encephalopathy (BSE), based on consumption of beef mechanically recovered meat (MRM) and head meat.

METHODS

Simulation (from vCJD infections generated randomly from gender and age-specific dietary exposure intensities to BSE), constrained to equal the 47 and 64 vCJD onsets before 2001 in 1940-1969 and post-1969 birth cohorts, was used to estimate lognormal (and other) incubation mean and standard deviation which fitted the calendar year distribution of observed vCJD onsets; and to explore exponential decay in susceptibility to infection with age above 15 years.

RESULTS

For the post-1969 birth cohort, the best-fitting lognormal incubation period mean of 11 years (SD 1.5 years and 195 infections) was associated with 194 vCJD onsets (64 before 2001, 105 in 2001-2005, and 25 in 2006-2010). About one-fifth of simulated vCJD onsets before 2001 arose from infections in 1990-1996; age and gender of simulated and observed vCJD patients agreed closely. For the 1940-1969 birth cohort, well-fitting lognormal means ranged widely, the marginally best fitting being 26 years (SD 16.5 years and 382 infections; 47 vCJD onsets before 2001, 58 in 2001-2005, and 63 in 2006-2010). An age-dependent susceptibility function was required to match the age distribution of vCJD patients in the 1940-1969 birth cohort.

CONCLUSIONS

About three-fifths of predicted vCJD onsets are expected to be in males, and nearly two-thirds of vCJD onsets in 2001-2005 are expected to be in post-1969 birth cohort according to best-fitting predictions.

UK bovine carcass meat consumed as burgers, sausages and other meat products: by birth cohort and gender

BACKGROUND

The most likely human exposure to bovine spongiform encephalopathy (BSE) is dietary, through beef mechanically recovered meat (MRM) and head meat used in burgers, sausages and other meat products. The majority, reportedly 90% of beef MRM and 80% of head meat, was used in burgers. To enable quantification of UK dietary exposure to BSE, we quantified bovine carcass meat consumed as burgers, sausages and other meat products by birth cohort, gender and calendar period (1980-1989, 1990-1996).

METHODS

Synthesis of dietary data (cross-sectional National Dietary and Nutrition Surveys, and serial National Food Surveys and Realeat Surveys) to simulate weekly consumption by one-thousandth of the UK population in each year from 1980 to 1996.

FINDINGS

In 1980-1989, the highest number of consumers (per 7 days) of all three food groups was in the 1940-1969 birth cohort - averaging 3.7 million male consumers of burgers, 2.6 million of sausages and 8.5 million of other meat products. The post-1969 birth cohort had the next highest number of consumers of burgers (1.8 million males). In 1990-1996, consumer numbers declined for the two older cohorts, most strikingly for burgers (down to 2.5 million males in the 1940-1969 cohort). The 1940-1969 cohort retained the highest number of consumers of sausages and other meat products, and second place for burgers. Male consumption was higher, even in the pre-1940 birth cohort where, for demographic reasons, female consumers outnumbered males. In the post-1969 birth cohort, female consumption of bovine carcass meat weight as burgers increased from 68 tonnes in 1980-1989 to 81 tonnes in 1990-1996, and male consumption increased more markedly (by 41%) from 84 tonnes to 119 tonnes; and similarly for other meat products.

INTERPRETATION

Properly marshalled age-group and gender-specific consumption data contribute to a clearer understanding of the demography of those who were at risk of dietary exposure to BSE and of when their exposure intensity was greatest. Other countries may need to consider using dietary data to model their human BSE exposure from UK and other BSE-affected regions.

UK dietary exposure to BSE in beef mechanically recovered meat: by birth cohort and gender

BACKGROUND

Meat recovered mechanically from bovine vertebral columns for use in burgers, sausages and other meat products may have been contaminated with bovine spongiform encephalopathy (BSE) from recovered spinal cord and dorsal root ganglia (DRG). We quantified UK exposure to BSE in beef mechanically recovered meat (MRM) by birth cohort (born pre-1940, in 1940-1969, post-1969), gender and calendar period (1980-1989, 1990-1996) because information on any two of BSE exposure intensity, vCJD incubation period and the new cases of vCJD tells us about the third.

METHODS

Synthesis of evidence on BSE epidemiology, MRM production, infectivity in spinal cord and DRG, and UK dietary consumption.

FINDINGS

Production of beef MRM peaked at 5000 tonnes in 1987, was nil in 1989 but recovered to 2000 tonnes in 1995 when it ceased altogether; reportedly 90% was used in burgers. Mean weight of spinal cord recovered per carcass was 3.3 g (95% credible interval 0.24-12.02 g) before the specified bovine offal (SBO) legislation and 1.5 g (0.02-8.30 g) after the legislation; whereas recovered weight of DRG (as infectious as spinal cord) was 27 g. Recovery of spinal cord from 1-year pre-clinical bovines peaked in 1988 at 238 g and of DRG in 1993 at 4250 g (medians). Median infectivity (5th and 95th percentiles) consumed in beef MRM was 33 250 (30 550-35 950), 65 600 (60 250-71 050) and 14 350 (13 150-15 600) bovine oral (Bo) ID50 units for the post-1969, 1940-1969 and pre-1940 birth cohorts in 1980-1989; and 44 250 (41 300-47 350), 39 600 (37 100-42,400) and 8750 (8100-9350) Bo ID50 units in 1990-1996. Males consumed almost 58% of infectivity in both periods. If the worst-case level of infectivity pertained, exposure, instead of halving in 1990-1996, would be sustained at around its 1980-1989 level for the two older birth cohorts and would have doubled in 1990-1996 for the post-1969 birth cohort.

INTERPRETATION

SBO legislation in 1989 contributed only a 6% reduction in the infectivity in beef MRM. Salient sensitivity issues are highlighted.

UK dietary exposure to BSE in head meat: by birth cohort and gender

BACKGROUND

UK dietary exposure in 1980-1996 to the bovine spongiform encephalopathy (BSE) infectious agent through the consumption of beef mechanically recovered meat (MRM) contained in burgers, sausages and other meat products has already been quantified by birth cohort (born pre-1940, 1940-1969 or post-1969) and gender. In this paper, similar quantification is undertaken for the consumption of bovine head meat.

METHODS

Synthesis of evidence on clinical BSE bovines, on bovines slaughtered in the last year of their BSE incubation period, brain contamination during head meat production, brain infectivity (option 1: 1-year preclinical bovine 54% as infectious as clinical BSE bovine; option 2: 1-year pre-clinical bovine as infectious as clinical BSE bovine) and 1980-1996 UK dietary consumption of head meat in burgers, sausages and other meat products.

FINDINGS

Median infectivity consumed in head meat was 49 900 (67 800 for infectivity option 2), 96 200 (126 900) and 24950 (32 800) bovine oral (Bo) ID 50 units for the post-1969, 1940-1969 and pre-1940 birth cohorts in 1980-1989; and 143 950 (266 550 for infectivity option 2), 150 900 (279 500) and 38 350 (71 250) Bo ID50 units in 1990-1996. Males consumed almost 58% of infectivity in 1980-1996. For all three birth cohorts, exposure to BSE in head meat was higher in 1990-96 for both infectivity options. Median infectivity consumed in head meat and beef MRM was 83 150 (109 000 for infectivity option 2), 161 900 (207 450) and 39 300 (50 450) Bo ID50 units for the post-1969, 1940-1969 and pre-1940 birth cohorts in 1980-1989; and 188 200 (348 700), 190 600 (353 050) and 47 200 (87 550) Bo ID50 units in 1990-1996.

INTERPRETATION

Males consumed almost 58% of BSE infectivity in head meat and beef MRM, which is consistent with 60 males of 113 variant Creutzfeldt-Jakeb disease (vCJD) onsets to 30 November 2001. If vCJD onsets to that date had all been infected in 1980-1989, 65 of 113 vCJD onsets in the post-1969 cohort are not consistent with its BSE exposure in 1980-1989 unless the vCJD incubation period or susceptibility depends on age, or another exposure is involved. Experimental data are needed to identify which brain material contaminates head meat, and further pathogenesis data are needed to determine the corresponding infectivity. Other salient sensitivity issues are highlighted.

Rationale and cost-efficiency compared for urine or saliva testing and behavioural inquiry among UK offender populations: injectors, arrestees and prisoners

BACKGROUND

Costs, methodology and efficiency at obtaining behavioural information and biological sample to be tested for blood-borne viruses or illegal drugs are compared for UK surveys of offender populations: injectors in the community or attending drug agencies, arrestees and prisoners.

METHODS

Arrestee surveys use extensive behavioural interview + urine sample and measure a key performance indicator in UK's Drugs Strategy. They have low efficiency (urine sample for drugs testing available from under 60% of eligible arrestees) at high cost (pound sterling 110-190 or 350 per urine sample and at least pound sterling 500-800 per injector). Random mandatory drugs testing of prisoners has the highest efficiency (because refusals are punishable), but the cost is high (pound sterling 110-120 per urine sample and pound sterling 300-500 per injector) and behavioural data are lacking. Prisoner surveys use self-completion questionnaire + saliva sample. They guarantee demonstrable anonymity in estimating the prevalence of blood-borne viruses and prisoners' associated risk behaviours, have high efficiency (saliva sample from over 80% of inmates) at low cost (pound sterling 30 per saliva and pound sterling 70-110 per injector), but behavioural data are limited to risk factors for blood-borne viruses. Low cost also characterises comprehensive interview + saliva sample from injectors in the community (pound sterling 90 per saliva sample, all from injectors) but efficiency cannot be assessed because the sampling frame of eligible injectors is not known. Voluntary unlinked anonymous surveys of injectors at drug agencies use self-completion questionnaire + saliva sample to be tested for blood-borne viruses. They are the least costly at pound sterling 43 per injector and moderately efficient with two-thirds volunteer rate by eligible injectors.

DISCUSSION

For scientific added-value, we recommend co-location of survey types geographically and temporally; a common core set of behavioural questions; saliva sample as well as (and, eventually, instead of) the less acceptable urine sample. Survey methodologies for measuring key performance indicators should stand up to scrutiny in terms of openness, design credentials, statistical power, and costs. We examine how participation bias or inadequate survey size can compromise the effective monitoring of a key performance indicator.

Projecting severe sequelae of injection-related hepatitis C virus epidemic in the UK. Part 1: Critical hepatitis C and injector data

BACKGROUND

Hepatitis C is transmitted by transfusion of unscreened blood, through injecting drugs, from mother-to-child and, on occasion, sexually. Transmission generally requires that the infector is hepatitis C virus (HCV) RNA positive, a 'carrier'. About three-quarters of injectors who are hepatitis C antibody positive are HCV-RNA positive and so infectious to others. Incubation periods from HCV infection to cirrhosis and hepatocellular carcinoma are even longer than from HIV infection to AIDS, being counted in decades; they depend on age, gender, alcohol consumption and co-infection with other viruses. We identify 25 data sources that are available, or required, for projecting the severe sequelae of the injection-related hepatitis C epidemic.

DATA SOURCES

Three data sources relate to hepatitis C diagnosis: register of confirmed HCV infections (with initial of first name + soundex of surname + date of birth + gender = master index, exposure category, year of starting to inject, and region); surveys of HCV test-uptake by injectors and others; documentation of pregnancy and its outcome in HCV-infected women (injectors and others). Four data sources relate to HCV prevalence and incidence among injectors and others: anonymous testing for HCV antibodies in blood or saliva (for sentinel groups ranging from new blood donors, pregnant women, patients awaiting kidney transplantation, non-injector prisoners, health-care workers, non-injector heterosexuals attending genitourinary medicine clinics; to injectors in the community, at drug treatment centres or in prison); historical data on HCV prevalence in injectors; HCV incidence studies in injectors; and uptake of harm reduction measures--frequency of sharing and methadone substitution--by injectors. Key reporting problems in HCV incidence studies, which inhibit checks on the convenient exponential assumption for time from start of injecting to hepatitis C infection, are discussed. Nine critical data sources are identified for monitoring the late sequelae of hepatitis C carriage, its investigation and treatment: linkage surveillance, for example by master index, to identify deaths, hospitalisations or cancer registrations among confirmed HCV infections; surveys of HCV status among patients who undergo liver biopsy, are newly diagnosed with cirrhosis or are newly diagnosed with liver cancer; surveys of liver-biopsy rate in HCV-infected injectors and others; uptake and outcome of interferon + ribavirin in the treatment of hepatitis C carriers; cohort studies of HCV progression; sample surveys of genotype in HCV-infected injectors, and others; acute hepatitis B infections and uptake of hepatitis B immunisation by injectors; liver transplantation in HCV-infected patients; and hepatitis C-status and other risk factors in deaths from cirrhosis or liver cancer, to determine whether they are HCV and injector-related. Finally, nine critical data sources are identified for quantitative understanding of the underlying injector epidemic: drug misuse databases plus capture-recapture methods to assess number of injectors, drug-related deaths by region to assess injector numbers; number of HIV-infected injectors; HIV progression in injectors; overdose and other causes of death in injectors; expert opinion on injector incidence historically, plus survey information on age-distribution at initiation and duration of injector careers; injector incidence historically inferred from hepatitis C infected blood donors; age-distribution of current injectors and at initiation, as a check on the assumptions made in stochastic simulation about injector incidence and 'outcidence' from injecting historically; mortality of former injectors; and general population or other survey ratios of surviving ever-injectors to injectors in the last 5 years, last year and currently, as a check on simulations.

RECOMMENDATIONS

We recommend a common HCV diagnosis report form to improve ascertainment of risk-factor information, especially year of starting to inject--which is a key date epidemiologically. We also recommend updated surveys of current and former injectors' HCV-test uptake, or a denominator study that registers master index and risk factor information for all HCV testees. We recommend that injector surveys ask about typical frequency of needle sharing per 4 weeks in three distinct periods this year, last year and in the first year of injecting. We also recommend the location of stored historical samples from injectors to be tested retrospectively and anonymously for HCV antibodies. We recommend immediate attention to the uptake of, and response to, combination treatment by hepatitis C carriers who are former or recovering injectors. We rec

Projecting severe sequelae of injection-related hepatitis C virus epidemic in the UK. Part 2: Preliminary UK estimates of prevalent injection-related hepatitis C carriers, and derivation of progression rates to liver cirrhosis by gender and age at hepatitis C virus infection

BACKGROUND

In Part 2, we illustrate how available data can be used to obtain preliminary estimates for Scotland of prevalent injection-related hepatitis C carriers and of maternally hepatitis C virus (HCV)-infected infants. Novel approaches to reducing uncertainty about the number of Scotland's HCV infected children of injector parents are discussed in brief. Three approaches, one direct and two indirect, to estimating the number of current and ever-injectors are presented for England and Wales.

METHODS

Diagnosed HCV infections in injectors and HCV test uptake by current injectors are combined with survey estimates for the ratio of ever-injectors to current injectors to estimate prevalent injection-related hepatitis C carriers. Household surveys give direct but potentially biased estimates of the number of current and ever-injectors. Indirect estimates make use of hepatitis C diagnoses in injectors, HCV prevalence and test-uptake by injectors, or exploit international comparisons. We comment on key reporting problems that inhibit synthesis of HCV progression studies; and suggest how to derive preliminary gender-and-age specific progression rates to liver cirrhosis for use in projections.

RESULTS

Preliminary estimates for Scotland of prevalent injection-related hepatitis C carriers are: central estimate 39,000, inner uncertainty 16,000-59,000; of maternally hepatitis C virus (HCV)-infected infants central estimate 260, uncertainty 110-1100; and for England and Wales estimates of the number of prevalent ever-injectors are central estimate 360,000, uncertainty 240,000-835,000. Both hepatitis C prevalence in injectors and estimated numbers of current injectors are similar in Australia, and England and Wales (but not so for Scotland), Australian work on projections of severe HCV sequelae from hepatitis C infections may therefore be a suitable starting point for projections for England and Wales. Australia anticipates a doubling in the number of persons living with hepatitis C cirrhosis from 8500 in 1997 to over 17,000 in 2010.

DISCUSSION

Australian projections of severe HCV sequelae used progression rates that, for simplicity, were independent of gender and of age at HCV infection. Faster HCV progression for males, and their higher injector prevalence, means that the impact of HCV infection on, for example, liver cancer may be evident to a greater extent and earlier in males.

Surveillance of HIV infection and related risk behaviour in European prisons. A multicentre pilot study

BACKGROUND

In order to demonstrate the feasibility of human immunodeficiency virus (HIV) infection and related risk behaviour surveillance in European prisons, a multicentre pilot study was undertaken.

METHODS

A cross-sectional survey was carried out in six European prisons (France, Germany, Italy, The Netherlands, Scotland and Sweden). Inmates were invited to complete a self-administered and anonymous questionnaire and to give a saliva sample in order to test for HIV antibodies.

RESULTS

Eight hundred and forty-seven out of 1,124 inmates participated in the survey (response rate 75%). Saliva from 817 inmates (73%) was collected and processed for HIV antibodies. Twenty-seven per cent reported that they had ever injected drugs and 49% of these reported they had injected whilst in prison. Eighteen per cent of inmates reported that they had been tattooed whilst in prison, which was found to be higher among injecting drug users (IDUs). One and sixteen per cent reported that they had ever had homosexual and heterosexual intercourse in prison respectively. The HIV prevalence among IDUs was 4% (versus 1% among non-IDUs) (p = 0.02). The proportions of inmates previously tested for hepatitis C and vaccinated against hepatitis B were 24 and 16% respectively.

CONCLUSION

This survey demonstrates the feasibility of cross-sectional surveys in European prison inmates and highlights the importance of surveillance of HIV prevalence and related risk behaviour among inmates. The continuing high HIV prevalence and potential for HIV spread in prisons should encourage decision makers in implementing or enhancing harm reduction and education programmes and substance abuse treatment services in prison.

Proportional hazards model for interval-censored failure times and time-dependent covariates: application to hazard of HIV infection of injecting drug users in prison

Interval-censored survival data are data in which the failure times are not known precisely, but are known to lie within an interval. Such data can be analysed using a proportional hazards model with piecewise-exponential baseline hazard, a model which can be fitted by an EM algorithm easily programmed in standard statistical software. In this paper we extend the model to allow for time-dependent covariates and left-truncation, and demonstrate its use by assessing the effect of imprisonment on hazard of HIV infection in a cohort of injecting drug users from Edinburgh. No conclusive effect of incarceration on hazard of HIV infection was found, but there was a suggestion that imprisonment might have been a significant relative risk factor for infection in the later period, when risk behaviour among drug users in the community was reduced.

Prevalence of detectable abnormal prion protein in persons incubating vCJD: plausible incubation periods and cautious inference

BACKGROUND

Both small and large variant Creutzfeldt Jakob disease (vCJD) epidemics are consistent with the current observed incidence. Uncertainty in vCJD projections could potentially be reduced by incorporating information on the prevalence of the infectious agent in persons incubating vCJD. The prospect of vCJD prevalence studies has been raised by detection of abnormal prion protein, thought to be the infectious agent, in appendices and tonsils removed from vCJD patients. Although unlinked anonymous testing of stored operative tissues for abnormal prion protein is very appealing, the design and interpretation of such prevalence studies is complicated by the lack of information on how early in the incubation period of vCJD the abnormal prion protein becomes detectable.

METHODS

We simulate a range of vCJD epidemics, consistent with the limited available information on the incidence of vCJD, to illustrate some of the potential problems encountered when interpreting the results from prevalence studies of detectable abnormal prion protein. We assume plausible incubation period distributions and dietary exposure patterns.

RESULTS

We demonstrate, in the context of our simulated epidemics, that prevalence studies of detectable abnormal prion protein would require the testing of tens of thousands of operative specimens and, even then, that unlinked anonymous testing positives would be unexpected.

Historical HIV prevalence in Edinburgh Prison: a database-linkage study

BACKGROUND

The prevalence of HIV in prisons is often higher than in the surrounding community, because prisons contain a high proportion of injecting drug users (IDUs). Reliable estimation of HIV prevalence in UK prisons only began in the 1990s. Edinburgh, Scotland, experienced a major IDU-related HIV epidemic which began in 1983. We sought retrospectively to estimate HIV prevalence in Edinburgh Prison over the period 1983-94.

METHODS

Prison records of all 477 male HIV-positive patients (332 IDUs) in the Edinburgh City Hospital Cohort (believed to include three-quarters of HIV-positive Edinburgh IDUs) were abstracted from Edinburgh Prison. Using this information and the seroconversion intervals of the patients, the number of person-years spent inside the prison by these individuals while HIV-positive was estimated for each calendar month. From this, HIV prevalence was inferred.

RESULTS

HIV prevalence in the prison rose from January 1983, as prevalence among Edinburgh IDUs increased, reaching a peak of 8% in December 1984. Prevalence during 1985-86 was 5-6% and then gradually declined, as the surviving HIV-infected IDUs spent less time in the prison.

DISCUSSION

These figures are probably underestimates, as some HIV-positive prisoners are not in the cohort. However, the degree of underestimation should not be great and trends over time are reliable. Our estimate for August 1991, 4.1%, compares favourably with the estimate 4.5%, from an anonymous unlinked survey conducted in the prison that month. Prevalence estimates from other UK prisons are reviewed and suggestions made for other uses of database linkage in HIV and IDU epidemiology.

Partner notification in HIV-1 infection: a population based evaluation of process and outcomes in Scotland

OBJECTIVES

To evaluate the process and outcomes of HIV partner notification (PN) activity in Scotland.

DESIGN

Retrospective population based study.

SUBJECTS

114 adults newly diagnosed with HIV infection (index patients) in Scotland between September 1995 and August 1996.

SETTING

Healthcare settings in which all 114 new HIV diagnoses were made: 42 (37%) from genitourinary medicine; 32 (28%) infectious diseases; 18 (16%) general practice; and 22 (19%) from other sites.

MAIN OUTCOME MEASURES

Number of partners notified and tested up to 9 months after initial diagnosis.

RESULTS

Of 114 index patients (IPs), information on current partners was available for 102 (89%). PN was not appropriate for 47 of the 102 IPs. The remaining 55 IPs identified 63 current partners at risk, of whom 51 were notified: 44 underwent HIV testing, which yielded 11 new HIV positive diagnoses. Information on previous partners was available for only 56 IPs (49%). PN was not appropriate for 30 of the 56 IPs; the remaining 26 IPs identified 46 previous partners at risk, of whom 12 were notified: four were tested, but yielded no new diagnoses.

CONCLUSIONS

Notification of current partners was performed well and was an effective strategy for identification of HIV positive individuals at a presymptomatic stage. Notification of previous partners was limited. Partner notification was attempted in a wide range of healthcare settings. Given the clinical effectiveness of antiretroviral therapy, partner notification as a tool towards early diagnosis of HIV disease deserves renewed attention.

The effect of altering eligibility criteria for entry onto a kidney transplant waiting list

BACKGROUND

This paper concerns the allocation of kidneys from cadaveric donors to patients with end-stage renal disease (ESRD). Currently, the decision as to whether or not a particular patient should go onto the renal transplant waiting list is left to the discretion of the local dialysis centre, and is usually based almost entirely upon consideration of each case on its individual merits. Would this person like to have a renal transplant, is this possible, and would it seem reasonable to give them a chance? It could be argued that such an approach may not make best use of a scarce national resource. In this study we explore the effects of altering the eligibility criteria for transplantation to take explicit and quantitative account of the fact that some patients are more likely to die than others.

METHODS

We performed a survey of one unit's dialysis patients to ascertain the characteristics used in practice to determine who should go onto the transplant waiting list and who should not. We then created a computer model to simulate a cohort of ESRD patients, initially of the same size and characteristics as that in the unit surveyed, receiving renal replacement therapy over a period of 10 years. Using this model, we compared four strategies for defining eligibility for transplantation: (1) all patients eligible; (2) standard and medium risk patients eligible; (3) only standard risk patients eligible; and (4) no regrafts performed (standard and medium risk according to definitions in the Renal Association Standards Document).

RESULTS

Strategies of allowing only standard or standard and medium risk patients onto the waiting list most closely reflected the current decisions made regarding eligibility. The different strategies considered in the models necessarily gave rise to very considerable variation in the size of the waiting list at the end of the 10 year period (range 98-368), which would have important practical implications. The predicted mean time of kidney function varied from 9.8 years for strategy 4 (no regrafts) to 10.8 years for strategy 3 (only standard risk patients eligible). However, the different strategies had very little effect on other parameters, such as numbers of deaths and the size of the dialysis population.

CONCLUSIONS

Variation in decision making from centre to centre regarding access to renal transplantation could make up to a 10% (1 year) difference in the expected half-life of renal transplants performed. Information about recipient characteristics is therefore required when making comparisons between outcome in one transplant unit with that in another, or when comparing one immunosuppressive regime with another.

Therapeutic effects of oral zinc in acute and persistent diarrhea in children in developing countries: pooled analysis of randomized controlled trials

BACKGROUND

Zinc deficiency is prevalent in children in developing countries. Supplemental zinc provides therapeutic benefits in diarrhea.

OBJECTIVE

We sought to measure the effect of supplemental zinc given with oral rehydration therapy during recovery from acute or persistent diarrhea.

DESIGN

We conducted pooled analyses including all available published and unpublished randomized controlled trials of the effects of supplementary oral zinc in children aged <5 y with acute or persistent diarrhea. We used Cox survival regression analysis to evaluate the overall effect of zinc on continuation of diarrhea and possible differential effects in subgroups divided by sex, age, weight-for-height, and initial plasma zinc concentration. Dichotomous outcomes were analyzed by logistic regression. To assess the effects of excluding studies without original data from the pooled analyses, effect-size was estimated for all studies by using random-effects models.

RESULTS

Zinc-supplemented children had a 15% lower probability of continuing diarrhea on a given day (95% CI: 5%, 24%) in the acute-diarrhea trials and a 24% lower probability of continuing diarrhea (95% CI: 9%, 37%) and a 42% lower rate of treatment failure or death (95% CI: 10%, 63%) in the persistent-diarrhea trials. In none of the subgroup analyses were the 2 subgroups of each pair significantly different from each other; however, in persistent diarrhea there tended to be a greater effect in subjects aged <12 mo, who were male, or who had wasting or lower baseline plasma zinc concentrations.

CONCLUSION

Zinc supplementation reduces the duration and severity of acute and persistent diarrhea.

High-performance liquid chromatography of selenoamino acids and organo selenium compounds. Speciation by inductively coupled plasma mass spectrometry

As part of an ongoing study to identify selenium compounds with cancer chemopreventive activity, extracts of selenium-enriched samples were analyzed by HPLC-inductively coupled plasma (ICP)-MS. Ion-exchange, ion pair and derivatization methods for reversed-phase HPLC were considered and advantages and disadvantages for each compared. Anion exchange allows separation of selenite and selenate, but otherwise provides poor separation. Pre-column derivatization and reversed-phase chromatography provides separation of compounds with terminal amine functionalities, but many other species elute in the void volume. The ion pair method gave optimal separation and was compatible with standard ICP-MS operating conditions.

Immediate transbiliary embolization of a biliary-hepatic artery fistula encountered during access for percutaneous biliary drainage

The authors describe a case in which a biliary-hepatic artery fistula was created by a glidewire perforation during percutaneous transhepatic biliary drainage and was successfully treated by embolization via the transbiliary tract. Great caution should be exercised to avoid perforation when a Terumo hydrophilic glidewire is used during biliary intervention.