Military fatality rates (by cause) in Afghanistan and Iraq: a measure of hostilities

BACKGROUND

Military fatalities occur in clusters, and causes differ between theatres of operation or within-theatre over time.

AIM

Based on around 500 coalition deaths, identify major causes in Iraq and Afghanistan. For consecutive periods (1: May 1 to September 17, 2006, 2: September 18, 2006 to February 4, 2007), ascertain UK and others' numbers deployed to compare fatality rates per 1000-personnel years. Take account of clustering: deaths per fatal improvised explosive device (IED) incident, and in making short-term projections for Afghanistan.

METHODS

Cause and date of coalition deaths in Iraq and Afghanistan are as listed in http://www.iCasualties.org, where each death is designated as hostile or non-hostile. Numbers deployed in 2006 were available for UK and Canada, and for US to Iraq.

FINDINGS

Out of 537 coalition fatalities in Iraq in 2006 to September 17, 2006, 457 (85%) were hostile, but only half were in Afghanistan (October 2001 to September 17, 2006: 52%, 249/478). Air losses accounted for 5% fatalities in Iraq, but 32% in Afghanistan. IEDs claimed three out of five hostile deaths in Iraq, only a quarter in Afghanistan. Deaths per fatal IED incident averaged 1.5. In period 1, 50/117 military deaths in Afghanistan were UK or Canadian from 6750 personnel, a fatality rate of 19/1000/year, nearly four times the US rate of 5/1000/year in Iraq (based on 280 deaths). Sixty out of 117 fatalities in Afghanistan occurred as clusters of two or more deaths. In period 2, fatality rates changed: down by two-thirds in Afghanistan for UK and Canadian forces to 6/1000/year (18 deaths), up by 46% for US troops in Iraq to 7.5/1000/year (416 deaths).

INTERPRETATION

Rate, and cause, of military fatalities are capable of abrupt change, as happened in Iraq (rate) and Afghanistan (rate and cause) between consecutive 140-day periods. Forecasts can be wide of the mark.

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.

Influence of alcohol on the progression of hepatitis C virus infection: a meta-analysis

BACKGROUND & AIMS

A convincing, yet inconsistent, pattern has emerged that demonstrates increased progression of HCV-related liver disease with heavy alcohol use. The aim was to perform a meta-analysis to quantify the effect of alcohol on cirrhosis risk among persons infected with HCV.

METHODS

A meta-analysis of 20 articles, involving more than 15,000 HCV chronically infected persons, published between 1995 and 2004 was undertaken to explore the relationship between advanced liver disease and the consumption of alcohol.

RESULTS

The pooled relative risk of cirrhosis associated with heavy alcohol intake (defined in the range of at least 210-560 g per week) was 2.33 (95% confidence interval, 1.67-3.26) by the random effects model. The risk of HCV-related liver disease associated with heavy alcohol intake increased with severity of the outcome; the lowest (1.63; 95% confidence interval, 1.22-2.17) and highest (3.54; 2.14-5.85) pooled relative risk estimates were obtained for advanced fibrosis and decompensated cirrhosis, respectively. The regression effect of alcohol might, however, be underestimated in studies investigating the risk of HCV-related cirrhosis because they necessarily include patients undergoing liver biopsy and could therefore under-represent heavy alcohol users.

CONCLUSIONS

The evidence overwhelmingly shows a worsened outcome for those with chronic HCV and concurrent alcohol use. Studies varied widely in their definition of significant alcohol intake, and so the true threshold above which alcohol accelerates HCV disease progression remains uncertain. Alcohol consumption should be minimized as much as possible in those who have chronic HCV until a safe threshold is more definitively determined.

Prior information in behavioral capture-recapture methods: demographic influences on drug injectors' propensity to be listed in data sources and their drug-related mortality

The authors present findings from a Bayesian analysis of Scotland's four primary capture-recapture data sources for 2000 that was carried out to estimate numbers of current injecting drug users by region (Greater Glasgow vs. elsewhere in Scotland), sex (male vs. female), and age group (15-34 years vs. > or =35 years). A secondary goal of the analysis was to obtain Bayesian estimates and credible intervals for the demographic influences on Scotland's drug-related death rate per 100 current injectors. Incorporation of informative priors altered the models with highest posterior probability. Expert opinion on how demography influenced Scottish drug injectors' propensity to be listed in different data sources was taken into account, along with external information about European injectors' drug-related death rates and male:female ratios. Higher drug-related mortality was confirmed in older drug injectors and those outside of Greater Glasgow. Female injectors' lower drug-related death rate was not sustained beyond 34 years of age. The authors recommend that demographic influences be accommodated in behavioral capture-recapture estimation, especially when it is a prelude to secondary analysis, such as the analysis of drug-related death rates presented here.

Modeling the current and future disease burden of hepatitis C among injection drug users in Scotland

Quantitative estimates of the current and future burden of hepatitis C virus (HCV) disease are required to plan a public health response to the HCV epidemic with regard to both prevention and treatment. A forward projection model was used to estimate the numbers of both current and former injecting drug users (IDUs) who acquired HCV and progressed to moderate and severe disease in Glasgow and Scotland during 1960-2030. The model was designed to synthesize information on the incidence and cessation of injecting drug use, the incidence of HCV infection among IDUs, the rate of HCV disease progression, and the annual number of IDUs developing HCV-related decompensated cirrhosis. During 2003, a total of 17,400 and 42,900 HCV-infected IDUs were estimated in Glasgow and Scotland, respectively; this compares with approximately 5,000 and 13,900 diagnosed, respectively, and 13,200 and 32,200 with chronic HCV, respectively. The number of IDUs developing HCV-related decompensated cirrhosis in Scotland is estimated to double between 2000 and 2020. As many as 16% and 27% of former IDUs in 2005 aged 30-39 and 40-49 years, respectively, were estimated to have moderate disease, which highlights the potential benefit of targeting HCV testing at former IDUs who belong to these age groups. In conclusion, the identification and treatment of a larger proportion of former IDUs with HCV disease and education about the importance of minimal alcohol consumption are needed to help achieve a greater impact on the future morbidity and mortality of this disease.

Sudden rise in uptake of hepatitis B vaccination among injecting drug users associated with a universal vaccine programme in prisons

Hitherto, services have failed to deliver the UK Government's 1988 recommendation to vaccinate injecting drug users (IDUs) against hepatitis B virus (HBV). In April 1999, the Scottish Prison Service implemented an initiative to offer HBV vaccination to all inmates; we sought to determine the impact of this initiative on the IDU population. Among community-recruited IDUs (who had injected for < or =5 years) in Glasgow, vaccine uptake was significantly higher among those surveyed in 2001-2002 (52% of 387) than in 1993 (16% of 166), 1994 (19% of 138) or January-March 1999 (15% of 128); of the 2001-2002 vaccinees, 56% had been vaccinated in prison. Our results indicate that the universal offer of vaccination to all prisoners, within two years of the initiative's implementation, has had a dramatic impact on uptake among IDUs.

Attributable testing for abnormal prion protein, database linkage, and blood-borne vCJD risks

CONTEXT

National prospective collection of tonsillar tissue to be tested anonymously for abnormal lymphoreticular accumulation of prion protein (PrP) was approved to begin in the UK in 2004. The UK is not, however, testing autopsy specimens attributably for abnormal PrP (PrP(SC)) so that recipients at risk after a blood transfusion from, or exposed to surgical instruments from, a deceased carrier of variant Creutzfeldt-Jakob disease (vCJD) can be followed up to quantify transmission risks. In Switzerland, surveillance for subclinical vCJD includes unconsented testing in autopsies: consented testing of tonsillar tissue is potentially attributable to interrupt human-to-human vCJD transmission or treat it.

STARTING POINT

The UK announced its first case of probable blood-borne vCJD transmission in December, 2003, and first detected a case of probable blood-borne subclinical vCJD in July, 2004. To reduce the possible risk of onward transmission to other people, UK patients who had received vCJD-implicated plasma products are being contacted. They, and their general practitioner, are asked to inform anyone giving them medical, surgical, or dental treatment, and the patients must refrain from donating blood, tissues, or organs. WHERE NEXT? Prudent additional surveillance options for human PrP(SC)--particularly at autopsy or to sanction the release of quarantined operation sets pending effective decontamination--can be costed by reference to results for cattle and sheep. Some ethical or legal impediments to the UK's potentially-attributable testing for PrP(SC) may yet be rued.

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.

Drug-related deaths by region, sex, and age group per 100 injecting drug users in Scotland, 2000-01

BACKGROUND

In 2000 and 2001, there were 292 and 332 drug-related deaths in Scotland, respectively. Of the 332 people who died in 2001, 65 were of female sex, 80 were younger than 25 years, and 112 were older than 34 years. We assessed the effect of region, sex, and age group on drug-related deaths in Scotland per 100 injecting drug users.

METHODS

We used published regional estimates of current injecting drug users (n=22805), their sex (30% female) and age distribution (8% older than 34 years in mid-1990s), or corresponding data for problem drug users (21% older than 34 years in 2000) to compare observed with expected drug-related deaths by region, sex, and age group per 1000 population or per 100 injecting drug users.

FINDINGS

Regional population-based expectations fitted poorly to observed drug-related deaths, but those based on injecting drug users fitted tolerably. Drug-related deaths in 2001 per 100 injecting drug users were significantly lower in female (0.9 [95% CI 0.6-1.1]) than in male drug users (1.5; 1.3-1.7). They were between two and six times more frequent per 100 injecting drug users older than 34 years than younger than 25 years, depending on whether current injecting drug users' age distribution was assumed to be the same as problem drug users' or as injecting drug users' in the mid-1990s (2.1 [1.7-2.5] or 5.3 [4.3-6.3], respectively).

INTERPRETATION

Older and male injecting drug users were at highest risk of drug-related death. Injecting drug users' age distribution should be assessed and compared across countries.

European Union's rapid TSE testing in adult cattle and sheep: implementation and results in 2001 and 2002

After the discovery of variant Creutzfeldt-Jakob disease (vCJD), scientific advances quickly led to post-mortem tests to identify late-stage bovine spongiform encephalopathy (BSE) disease. These were first used in Switzerland in 1999 for active BSE surveillance of a) fallen and emergency-slaughter bovines (risk stock) and b) 5% sample of routinely slaughtered cattle over 30 months of age. In 1999 and 2000, Switzerland's estimated 103 BSE positives per 1000000 adult cattle put it in the same BSE risk classification as UK and Portugal. In July 2000, the European Union's Scientific Steering Committee published its methodology (and first vetted results) for geographical BSE risk (GBR) assessment in cattle. Member states with no BSE cases found themselves, on rational assessment, classified as GBR III (BSE likely but not confirmed, or confirmed at a lower level). Because of Europe's thus highly assessed BSE risks, active BSE surveillance of adult cattle in all member states began in January 2001 using one of three validated post-mortem tests. Implementation was variable across member states in January to March 2001 but, where operational, active surveillance was typically achieved for around 13300 routinely slaughtered and 1000 risk stock per month per 1000000 adult cattle; BSE positive rates were 60 and 600 per 1000000 routinely slaughtered and risk cattle, respectively. By the second half of 2001, active BSE surveillance was operating reasonably in most member states, although anomalies persisted. Performance and results for July to December 2001 and for January to June 2002 are considered in detail. The BSE positive rate decreased substantially in UK, Portugal and Ireland between semesters, whereas Spain's rates increased for both routinely slaughtered and risk bovines. Based on 1450000 routinely slaughtered and 135000 risk stock as standard, France could have expected 153 BSE positives in July to December 2001 (109 in January to June 2002); Italy 154 (67); and Germany only 39 (48). When sample-based surveillance data were scaled up and combined with clinical BSE cases, Great Britain's BSE positives were estimated at around 400 per 1000000 adult cattle in 2002 compared with over 1000 per 1000000 adult cattle in 2000. Age distributions for cattle subject to active BSE surveillance have been underexploited. The major transmissible spongiform encephalopathy (TSE) which affects sheep and goats is scrapie. Passive surveillance of scrapie is associated with substantial under-reporting. Susceptibility to scrapie depends strongly on sheep genotype; but resistance to scrapie does not necessarily confer resistance of sheep to BSE. Because of uncertainty about the true prevalence of scrapie-infected adult sheep and concern that BSE in sheep may be missed, the European Union pre-empted its planned evaluation of rapid post-mortem TSE tests in sheep by requiring the rapid TSE testing of small ruminants from April 2002 with one of the three cattle-validated tests. Basic requirements for active TSE surveillance in sheep were: random sample of 6000 fallen sheep and of 60000 routinely slaughtered adult native sheep to be tested per member state by end March 2003. Lower surveillance targets were set for countries with under 1000000 adult sheep. Adequately to map scrapie-susceptible genotypes and identify resistant genotypes, a random sample of 500 routinely slaughtered native adult sheep was to be genotyped, together with each TSE rapid test positive adult sheep and two sets of three suitably sampled controls. By the end of August 2002, when 41% of the initial surveillance time had elapsed, only 20% of the European joint target for routinely slaughtered adult sheep had been completed, but that for fallen sheep was exceeded. Except in Ireland, the upper 95% confidence bound on TSE prevalence exceeded 500 per 1000000 routinely slaughtered adult sheep in reporting-compliant countries with more than 1000000 adult sheep. The UK, Greece, Italy and France were likely to approach the goal of 100 TSE rapid test positives on completion of their assigned first-year surveillance target for sheep. Results from the recommended genotyping of TSE positive adult sheep and controls for use in inferring differential TSE-positive susceptibility by genotype are awaited. Only by genotyping 5000-50000 TSE-positive adult sheep, a massive undertaking even on the European scale, will it become clear whether scrapie resistance is relative rather than absolute. This paper details Europe's quantitative evolution in TSE surveillance.

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.

Male drugs-related deaths in the fortnight after release from prison: Scotland, 1996-99

AIMS

To assess if 15-35-year-old males released after 14 + days' imprisonment in Scotland, 1996-99, had a higher drugs-related death rate in 2 weeks after release than during subsequent 10 weeks; higher than expected death rate from other causes; and if drugs-related deaths in the first fortnight were three times as many as prison suicides.

DESIGN

Confidential linkage of ex-prisoner database against deaths.

SETTING

Scotland's male prisons and young offenders' institutions during July to December 1996-99; 19 486 index releases after 14+ days' incarceration.

MEASUREMENTS

Relative risk of drugs-related death in the first 2 weeks after release (34 deaths) versus subsequent 10 weeks (23). Other causes of death (21) relative to expectation. Drugs-related deaths in first 2 weeks after release relative to suicides in prison (12).

FINDINGS

Drugs-related mortality in 1996-99 was seven times higher (95% CI: 3.3-16.3) in the 2 weeks after release than at other times at liberty and 2.8 times higher than prison suicides (95% CI: 1.5-3.5) by males aged 15-35 years who had been incarcerated for 14+ days. We estimated one drugs-related death in the 2 weeks after release per 200 adult male injectors released from 14 + days' incarceration. Non-drugs-related deaths in the 12 weeks after release were 4.9 times (95% CI: 2.8-7.0) the 4.3 deaths expected.

CONCLUSION

Investment in, and evaluation of, prison-based interventions is needed to reduce substantially recently released drugs-related deaths.

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.