A small area analysis estimating the prevalence of addiction to opioids in Barcelona, 1993

Estimating hidden populations by transferring knowledge from geographically misaligned levels

The estimation of hidden sub-populations is a hard task that appears in many fields. For example, public health planning in Brazil depends crucially of the number of people who holds a private health insurance plan and hence rarely uses the public services. Different sources of information about these sub-populations may be available at different geographical levels. The available information can be transferred between these different geographic levels to improve the estimation of the hidden population size. In this study, we propose a model that use individual level information to learn about the dependence between the response variable and explanatory variables by proposing a family of link functions with asymptotes that are flexible enough to represent the real aspects of the data and robust to departures from the model. We use the fitted model to estimate the size of the sub-population at any desired level. We illustrate our methodology estimating the sub-population that uses the public health system in each neighborhood of large cities in Brazil.

The Experience of Implementing Urban HEART Barcelona: a Tool for Action

Urban Health Equity Assessment and Response Tool (HEART) is a tool developed by the World Health Organization whose objective is to provide evidence on urban health inequalities so as to help to decide the best interventions aimed to promote urban health equity. The aim of this paper is to describe the experience of implementing Urban HEART in Barcelona city, both the adaptation of Urban HEART to the city of Barcelona, its use as a means of identifying and monitoring health inequalities among city neighbourhoods, and the difficulties and barriers encountered throughout the process. Although ASPB public health technicians participated in the Urban HEART Advisory Group, had large experience in health inequalities analysis and research and showed interest in implementing the tool, it was not until 2015, when the city council was governed by a new left-wing party for which reducing health inequalities was a priority that Urban HEART could be used. A provisional matrix was developed, including both health and health determinant indicators, which allowed to show how some neighbourhoods in the city systematically fare worse for most of the indicators while others systematically fare better. It also allowed to identify 18 neighbourhoods-those which fared worse in most indicators-which were considered a priority for intervention, which entered the Health in the Barcelona Neighbourhoods programme and the Neighbourhoods Plan. This provisional version was reviewed and improved by the Urban HEART Barcelona Working Group. Technicians with experience in public health and/or in indicator and database management were asked to indicate suitability and relevance from a list of potential indicators. The definitive Urban HEART Barcelona version included 15 indicators from the five Urban HEART domains and improved the previous version in several requirements. Several barriers were encountered, such as having to estimate indicators in scarcely populated areas or finding adequate indicators for the physical context domain. In conclusion, the Urban HEART tool allowed to identify urban inequalities in the city of Barcelona and to include health inequalities in the public debate. It also allowed to reinforce the community health programme Health in the Barcelona Neighbourhoods as well as other city programmes aimed at reducing health inequalities. A strong political will is essential to place health inequalities in the political agenda and implement policies to tackle them.

Estimating the likely true changes in rheumatic fever incidence using two data sources

Acute rheumatic fever (ARF) continues to produce a significant burden of disease in New Zealand (NZ) Māori and Pacific peoples. Serious limitations in national surveillance data mean that accurate case totals cannot be generated. Given the changing epidemiology of ARF in NZ and the major national rheumatic fever prevention programme (2012-2017), we updated our previous likely true case number estimates using capture-recapture analyses. Aims were to estimate the likely true incidence of ARF in NZ and comment on the changing ability to detect cases. Data were obtained from national hospitalisation and notification databases. The Chapman Estimate partially adjusted for bias. An estimated 2342 likely true new cases arose from 1997 to 2015, giving a mean annual incidence of 2·9 per 100 000 (95% CI 2·5-3·5). Compared with the pre-intervention (2009-2011) baseline incidence (3·4 per 100 000, 95% CI 2·9-4·0), the likely true 2015 incidence declined 44%. Large gaps in data completeness are slowly closing. During the period 2012-2015, 723 cases were identified; 83·8% of notifications were matched to hospitalisation data, and 87·2% of hospitalisations matched to notifications. Despite this improvement, clinicians need to remain aware of the need to notify atypical patients. A possible unintended consequence of the national ARF prevention programme is increased misdiagnosis.

Estimating rheumatic fever incidence in New Zealand using multiple data sources

Rheumatic fever (RF) is an important public health problem in New Zealand (NZ). There are three sources of RF surveillance data, all with major limitations that prevent NZ generating accurate epidemiological information. We aimed to estimate the likely RF incidence using multiple surveillance data sources. National RF hospitalization and notification data were obtained, covering the periods 1988-2011 and 1997-2011, respectively. Data were also obtained from four regional registers: Wellington, Waikato, Hawke's Bay and Rotorua. Coded patient identifiers were used to calculate the proportion of individuals who could be matched between datasets. Capture-recapture analyses were used to calculate the likely number of true RF cases for the period 1997-2011. A range of scenarios were used to correct for likely dataset incompleteness. The estimated sensitivity of each data source was calculated. Patients who were male, Māori or Pacific, aged 5-15 years and met the Jones criteria, were most likely to be matched between national datasets. All registers appeared incomplete. An average of 113 new initial cases occurred annually. Sensitivity was estimated at 80% for the hospitalization dataset and 60% for the notification dataset. There is a clear need to develop a high-quality RF surveillance system, such as a national register. Such a system could link important data sources to provide effective, comprehensive national surveillance to support both strategy-focused and control-focused activities, helping reduce the incidence and impact of this disease. It is important to remind clinicians that RF cases do occur outside the well-characterized high-risk group.

Are cannabis prevalence estimates comparable across countries and regions? A cross-cultural validation using search engine query data

BACKGROUND

Prevalence estimation of cannabis use is usually based on self-report data. Although there is evidence on the reliability of this data source, its cross-cultural validity is still a major concern. External objective criteria are needed for this purpose. In this study, cannabis-related search engine query data are used as an external criterion.

METHODS

Data on cannabis use were taken from the 2007 European School Survey Project on Alcohol and Other Drugs (ESPAD). Provincial data came from three Italian nation-wide studies using the same methodology (2006-2008; ESPAD-Italia). Information on cannabis-related search engine query data was based on Google search volume indices (GSI). (1) Reliability analysis was conducted for GSI. (2) Latent measurement models of "true" cannabis prevalence were tested using perceived availability, web-based cannabis searches and self-reported prevalence as indicators. (3) Structure models were set up to test the influences of response tendencies and geographical position (latitude, longitude). In order to test the stability of the models, analyses were conducted on country level (Europe, US) and on provincial level in Italy.

RESULTS

Cannabis-related GSI were found to be highly reliable and constant over time. The overall measurement model was highly significant in both data sets. On country level, no significant effects of response bias indicators and geographical position on perceived availability, web-based cannabis searches and self-reported prevalence were found. On provincial level, latitude had a significant positive effect on availability indicating that perceived availability of cannabis in northern Italy was higher than expected from the other indicators.

CONCLUSION

Although GSI showed weaker associations with cannabis use than perceived availability, the findings underline the external validity and usefulness of search engine query data as external criteria. The findings suggest an acceptable relative comparability of national (provincial) prevalence estimates of cannabis use that are based on a common survey methodology. Search engine query data are a too weak indicator to base prevalence estimations on this source only, but in combination with other sources (waste water analysis, sales of cigarette paper) they may provide satisfactory estimates.

Drugscapes and the role of place and space in injection drug use-related HIV risk environments

Although considerable research has been conducted to identify the behavioural characteristics that predispose individuals to inject drugs or become infected with HIV via injection drug use, much less research has been conducted on structural and policy determinants, cultural norms, stigma, and ecological factors which may affect drug use risk behaviour, users' networks and HIV rates associated with drug use across geographic areas. For programme planners, whether official or grassroots, an understanding of place-based characteristics can help better identify risk environments to injection drug use-related HIV, and determine how to facilitate actions regarding public policy and harm reduction to aid in the reduction of risk. As such, we consider in this commentary the importance of geographic place and the socio-spatial and political processes related to place that may help determine where IDU-related HIV risk environments occur.

Applying the small-area estimation method to estimate a population eligible for breast cancer detection services

INTRODUCTION

Populations eligible for public health programs are often narrowly defined and, therefore, difficult to describe quantitatively, particularly at the local level, because of lack of data. This information, however, is vital for program planning and evaluation. We demonstrate the application of a statistical method using multiple sources of data to generate county estimates of women eligible for free breast cancer screening and diagnostic services through California's Cancer Detection Programs: Every Woman Counts.

METHODS

We used the small-area estimation method to determine the proportion of eligible women by county and racial/ethnic group. To do so, we included individual and community data in a generalized, linear, mixed-effect model.

RESULTS

Our method yielded widely varied estimated proportions of service-eligible women at the county level. In all counties, the estimated proportion of eligible women was higher for Hispanics than for whites, blacks, Asian/Pacific Islanders, or American Indian/Alaska Natives. Across counties, the estimated proportions of eligible Hispanic women varied more than did those of women of other races.

CONCLUSION

The small-area estimation method is a powerful tool for approximating narrowly defined eligible or target populations that are not represented fully in any one data source. The variability and reliability of the estimates are measurable and meaningful. Public health programs can use this method to estimate the size of local populations eligible for, or in need of, preventive health services and interventions.

Drug-related mortality and its impact on adult mortality in eight European countries

OBJECTIVE

To estimate the mortality rates from drug-related deaths and other causes among problem drug users and population attributable risk of death due to opiate use in eight study sites in Europe.

METHODS

Opiate users were recruited from drug treatment centres during the period 1990-1998 and deaths followed up through national or local mortality registries. Gender-specific overall mortality rate, proportion of deaths by cause (drug-related, HIV, other), standardized mortality ratios (SMRs), and the attributable risk fraction (ARF) were estimated.

RESULTS

Crude mortality rates varied from 1 per 100 person-years in the Dublin and London cohorts to 3.8 per 100 person-years in Barcelona. The highest drug-related mortality rate was 10 per 1,000 person-years in Barcelona; the rates were approximately 7 per 1,000 person-years in Denmark, London, Rome, and Vienna, and <3.5 per 1,000 person-years for the others cohorts. The mortality rate for AIDS was <2 per 1,000 person-years in all the cohorts except Lisbon, Rome, and Barcelona, for which it was approximately 6 per 1,000 person-years. The highest SMR among males was 21.1 in Barcelona, and among females the highest SMRs were 53.7 and 37.7 in Barcelona and Rome, respectively. In Denmark the ARF was 5%, whereas it was >10% in all other study sites and 24% in Barcelona.

CONCLUSION

Cohort mortality studies, especially in combination with estimates of prevalence, provide useful insights into the impact of opiate use on mortality across European countries and emphasize how preventing overall and drug-related deaths among opiate users can significantly improve the health of the population.

Evaluating the impact of methadone maintenance programmes on mortality due to overdose and aids in a cohort of heroin users in Spain

AIMS

To assess the relationship between methadone treatment (MT) and overdose and HIV/AIDS mortality among heroin users resident in Barcelona city.

DESIGN

All patients who started treatment in any treatment centre between 1992 and 1997 were included in a cohort the first time they were admitted for heroin addiction treatment. Follow-up controls were carried out every 9 months, on average, until 31 December 1999. Variables, both constant and varying over time, were fitted into Cox regression models.

FINDINGS

The study recruited 5049 patients, which provided 23,048.2 person-years. Fifty per cent were in MT during the study period; of the total cohort 1005 patients died: 38.4% due to AIDS, 34.7% to overdose and 27% to other causes. Overall mortality decreased from 5.9 deaths per 100 person-years in 1992 to 1.6 in 1999. Globally, life expectancy at birth was 39 years, 38 years lower than that of the general population. The main factor for overdose mortality was not being in MT at the time of death [relative ratio (RR) = 7.1]; other factors were being a current injector at baseline and being HIV positive. For AIDS mortality, the main factor was the calendar year (RR for 1996 versus 1999 = 4.6), the next major factor was more than 10 years of heroin consumption, followed by not being in MT, being unemployed, then having a prison record.

CONCLUSIONS

The observed mortality decline could be linked to the effectiveness of low-threshold MT. The life expectancy of heroin users increased by 21 years during the study period.

Prevalence of problematic cocaine consumption in a city of southern Europe, using capture-recapture with a single list

This study aims to determine the magnitude and characteristics of problematic cocaine consumption in the city of Barcelona, Spain. Capture-recapture with a single source was used to estimate prevalence. Log-linear regression models with interaction terms were fitted to the total sample and to subgroups according to other drugs consumed. Emergency room indicator data were obtained from the Barcelona Drug Information System. Drug-related emergencies of Barcelona residents for 1999 were analyzed. During 1999, a total of 4,035 drug-related emergencies were seen in Barcelona hospitals. Of these, 1,656 (41%) involved cocaine consumption; 41% of these patients had consumed cocaine with an opiate; 29% used cocaine with other substances; and 30% used cocaine alone. It was estimated that there was a total of 25,988 problematic cocaine users (95% confidence interval 11,782-58,064), yielding a rate of 31.27 per 1,000 inhabitants aged 15 to 54 years (95% confidence interval 14.2-69.9). The number of cocaine-related emergencies was high enough to allow capture-recapture to be applied, thus obtaining an estimate of the prevalence of problematic cocaine consumption, and high enough to characterize users according to different profiles. The use of capture-recapture with a single source can be interesting for problems related to the urban context.

Weighing social and economic determinants related to inequalities in mortality

It is well known that there are social inequalities in health. Following the ecological approach, unemployment has been one of the most used indicators to study social inequalities. The aim of the present study was to investigate the relationships between indicators of extreme poverty and social unrest, along with unemployment, and mortality in Barcelona, during the years 1989 to 1993. A cross-sectional ecological study was carried out using Primary Health Care Areas (PHCAs) as the unit of analysis. The study population consisted of residents in Barcelona City. The indicators studied as dependent variables were the age-standardized mortality rates of the following causes of death: total mortality; lung cancer; bronchitis, emphysema, and asthma; cirrhosis; cerebrovascular disease; ischemic heart disease; breast cancer; traffic accidents; acquired immunodeficiency syndrome (AIDS); and drug overdose. Independent variables were male unemployment rate of the primary health care areas and indicators of extreme poverty and social conflict. A descriptive analysis, a bivariate analysis using Spearman correlation coefficients, and a multivariate analysis fitting Poisson regression models were carried out. For the main results, one group of causes of death was associated only with unemployment: bronchitis, emphysema and asthma, cerebrovascular disease, and ischemic heart disease (both men and women); lung cancer (only among men); total mortality and cirrhosis (only among women). Among men, another group of causes of death was associated with extreme poverty and/or social unrest, as well as unemployment: total mortality, cirrhosis, and drug overdose. AIDS in men was only associated with extreme poverty and social unrest. We concluded that we see different types of relationships between deprivation and mortality. Unemployment has been related to mortality because of pathologies with socially accepted risk factors (tobacco and alcohol). Causes of death with risk factors not socially accepted (illegal drug use) have been related to indicators of marginality as well as unemployment.

[Prevention of drug abuse in the secondary school after the reform of the Spanish educational system. Implementation of several programs in the city of Barcelona, Spain]

OBJECTIVES

To evaluate the adoption of 3 different school-based drug abuse prevention programmes in secondary schools, analyzing some features of their implementation and the relationship between the percentage of schools adopting each intervention and the prevalence of addiction to opiates at district level.

METHODS

Mail survey with telephone follow-up to the 235 secondary schools located in Barcelona, carried out at the end of 1997-1998 school-year. A bivariate analysis of correlations (Spearman) was performed to assess the association between the percentage of schools having adopted each of the 3 prevention programmes in each city district, and the previously reported estimates of the prevalence rates of opiate addiction.

RESULTS

44.7% of all schools completed the survey, 38 of them (16.2% of respondents) had offered 1 of the programmes within the school-year, 20 schools (19.0%) offered 2 programmes, and 4 schools (3.0%) the 3 programmes. Statistically significant correlations were found for the adoption of different programs between districts, but not for the percentages of schools offering prevention programmes and the prevalence of opiate addiction.

CONCLUSIONS

Social and health needs, indicated by prevalence rates of opiate addiction, do not explain geographic inequalities in the adoption of prevention programmes. The need for prevention programmes aimed at risk groups is discussed.