Comparación de dos métodos para identificar los factores asociados al inicio del consumo de cannabis en un estudio de cohortes

ResumenObjetivoComparar la utilidad de 2 métodos analíticos multivariados, el análisis como casos y controles (CC) y como casos y controles anidados (CCa) en una cohorte, para identificar los factores asociados al inicio del consumo de cannabis.MétodosEstudio longitudinal con una muestra de 1.056 alumnos de primer curso de Educación Secundaria Obligatoria (ESO), seguidos anualmente hasta cuarto de ESO. En el análisis como CC se consideraron casos los que declararon, en el cuarto año, haber consumido cannabis y controles los que no habían consumido nunca, estimando modelos de regresión logística (RL). En el análisis como CCa, se compararon los casos de cada año de seguimiento con una muestra aleatoria de controles de riesgo en ese mismo año, estimando modelos de RL condicional.ResultadosEn el análisis como CC, se identificaron 6 variables en los chicos y 9 en las chicas en los modelos bivariados, y 3 en los chicos y 4 en las chicas en los multivariados. En el análisis como CCa se obtuvieron 17 variables en los modelos bivariados y 4 en los multivariados, tanto en los chicos como en las chicas. Los estimadores del análisis como CC tenían 1,2 veces más variabilidad.ConclusionesEl análisis como CCa permitió identificar un mayor número de factores asociados al consumo de cannabis y los estimadores fueron más precisos. El CCa puede ser una alternativa más eficiente frente al análisis como CC.AbstractObjectiveTo compare the utility of two multivariate analytic methods, case-control (CC) analysis and nested case-control (NCC) analysis in a cohort, to identify the factors associated with the onset of cannabis use.MethodsA longitudinal cohort study of a sample of secondary school students (n = 1,056) in the first year of secondary school was carried out. Participating students were followed-up annually until the fourth year of secondary school. In the CC analysis, students in the fourth year who reported having consumed cannabis at some time were considered cases and those who had never consumed cannabis were considered controls. Logistic regression (LR) models were estimated. In the NCC analysis, cases in each year of follow-up were compared with a random sample of controls at risk in the same year and conditional LR models were estimated. IResultsIn the CC analysis, 6 variables in boys and 9 variables in girls in bivariate models and 3 variables in boys and 4 variables in girls in multivariate models were identified. In the NCC analysis, 17 variables in univariate models and 4 in multivariate models were obtained in both boys and girls. The estimators of the CC analysis showed an average of 1.2-fold more variability.ConclusionsA higher number of factors associated with cannabis use were identified in the NCC analysis and the estimators were more precise. NCC could be a more efficient option than CC analysis

Impact of Co-Occurring Psychiatric Disorders on Retention in a Methadone Maintenance Program : An 18-Month Follow-Up Study

We assess the influence of co-occurring psychiatric disorders on retention in 189 opioid dependent patients in a methadone maintenance treatment (MMT) and determine the incidence of psychiatric co-morbidity during an 18-month follow-up period. About 68.5 % were retained in the MMT. Neither co-occurring mental disorders (chi-square = 0.303, df = 1, p = 0.622) nor methadone doses [85 (88.9) vs. 79.2 (85) mg/day, p = 0.672] were related to retention. In the follow-up period 19 new diagnoses were made, mainly major depression and antisocial and borderline personality disorders. Co-occurring psychiatric disorders should be assessed during MMT follow-up

A multi-state model to estimate incidence of heroin use

Background: Existing incidence estimates of heroin use are usually based on one information source. This study aims to incorporate more sources to estimate heroin use incidence trends in Spain between 1971 and 2005. Methods: A multi-state model was constructed, whereby the initial state "heroin consumer" is followed by transition to either "admitted to first treatment" or to "left heroin use" (i.e. permanent cessation or death). Heroin use incidence and probabilities of entering first treatment ever were estimated following a back-calculation approach. Results: The highest heroin use incidence rates in Spain, around 1.5 per 1,000 inhabitants aged 10-44, occurred between 1985 and 1990; subdividing by route of administration reveals higher incidences of injection between 1980 and 1985 (a mean of 0.62 per 1.000) and a peak for non-injectors in 1990 (0.867 per 1,000). Conclusions: A simple conceptual model for heroin users' trajectories related to treatment admission, provided a broader view of the historical trend of heroin use incidence in Spain

The choice of screening instrument matters: the case of problematic cannabis use screening in spanish population of adolescents

The aim of this study was to examine the feasibility of problem cannabis use screening instruments administration within wide school surveys, their psychometric properties, overlaps, and relationships with other variables. Students from 7 Spanish regions, aged 14-18, who attended secondary schools were sampled by two-stage cluster sampling (net sample 14,589). Standardized, anonymous questionnaire including DSM-IV cannabis abuse criteria, Cannabis Abuse Screening Test (CAST), and Severity of Dependence Scale (SDS) was self-completed with paper and pencil in the selected classrooms. Data was analysed using classical psychometric theory, bivariate tests, and multinomial logistic regression analysis. Not responding to instruments' items (10.5-12.3%) was associated with reporting less frequent cannabis use. The instruments overlapped partially, with 16.1% of positives being positive on all three. SDS was more likely to identify younger users with lower frequency of use who thought habitual cannabis use posed a considerable problem. CAST positivity was associated with frequent cannabis use and related problems. It is feasible to use short psychometric scales in wide school surveys, but one must carefully choose the screening instrument, as different instruments identify different groups of users. These may correspond to different types of problematic cannabis use; however, measurement bias seems to play a role too.This study was conducted with financial support of Delegación del Gobierno para el Plan Nacional sobre Drogas (DGPNSD), Madrid, Spain, and European Monitoring Centre for Drugs and Drug Addiction (EMCDDA), Lisbon, Portugal.The authors would like to acknowledge Colin Taylor for providing useful advice and comments throughout the paper preparation.S

Metodología de reclutamiento y características de una cohorte de jóvenes consumidores habituales de cocaína de tres ciudades españolas (Proyecto Itínere-cocaína)

ResumenFundamentoLos sistemas de información sociosanitaria que monitorizan el consumo de drogas no profundizan en el análisis de las características sociodemográficas y de los patrones de consumo, ni en los factores que condicionan los problemas de salud. Se describe la metodología de reclutamiento y las características de una cohorte de jóvenes consumidores de cocaína.MétodosCohorte prospectiva de 720 consumidores de cocaína que no consumen habitualmente heroína, captados en la comunidad, independientemente de los servicios asistenciales, mediante métodos de referencia en cadena en las áreas metropolitanas de Madrid, Barcelona y Sevilla. Cuestionario administrado por ordenador y parcialmente autoadministrado. Análisis estratificado por ciudad y por frecuencia de consumo de cocaína base.ResultadosEn los últimos 12 meses el 58,8% había consumido cocaína entre 1 y 2 días por semana; el 91,9% habitualmente la había esnifado, un 5,3% fumado y sólo un 2,8% inyectado; el 6,1% la había utilizado la mitad de las veces o más en forma de base. Hubo policonsumo con cannabis (93,6%), éxtasis (73,2%) y anfetaminas (60,6%); un 4,0% se había inyectado alguna droga. Los que habían usado «crack» (22,1%) tenían un menor nivel educativo, un consumo de cocaína más intenso, mayor prevalencia de consumo de otras drogas, en especial opioides, y prevalencia de inyección mucho más alta.ConclusionesEl estudio confirma y completa el perfil sociodemográfico y de consumo ofrecido por los sistemas de información basados en servicios o las encuestas poblacionales, en especial que una gran parte de los consumidores jóvenes son esporádicos y que existen dos subpoblaciones muy diferenciadas según el consumo o no de cocaína base.AbstractBackgroundHealth information systems that monitor drug use do not perform in-depth analyses of sociodemographic characteristics and patterns of use, or of the factors that influence health problems. We describe the recruitment methodology and characteristics of a cohort of young cocaine users.MethodsA prospective cohort of 720 cocaine users who were not regular heroin users, recruited in the community independently of the health services by chain referral methods in the metropolitan areas of Madrid, Barcelona and Seville was studied. A computer-administered and partially self-administered questionnaire was used. A stratified analysis by city and by frequency of base cocaine use was performed.ResultsIn the previous 12 months, 58.8% had used cocaine 1-2 days/week; 91.9% sniffed it regularly, 5.3 smoked it, and only 2.8% injected it; 6.1% had used it at least half the time in the form of base cocaine. Polydrug use was observed with cannabis (93.6%), ecstasy (73.2%) and amphetamines (60.6%). Approximately 4.0% had injected at least one drug. Crack users (22.1%) had a lower educational level, more intensive cocaine use, a higher prevalence of other drug use, especially opioids, and a much higher prevalence of injection.ConclusionsThis study confirms and completes the sociodemographic and drug profile provided by the information systems based on health services or population surveys. The results show that a large proportion of young cocaine users consume the drug sporadically and that two very different subpopulations exist, according to whether or not they use base cocaine

More than thirty years of illicit drugs in Spain: a bitter story with some messages for the future

The phenomenon of illicit drug use in Spain during the last thirty years has been marked by the extremely serious consequences of heroin use (mainly injecting). More than 300,000 persons were treated for heroin dependence, 20,000-25,000 died from overdose, 100,000 became infected with HIV through drug injection and quite more with hepatitis virus. Some of these consequences can be attributed to the delay in the implementation of effective interventions, such as methadone maintenance treatment (MMT). Currently, the decreasing number of injectors and the positive effects of interventions, mainly MMT, have led to an important decline of the mentioned health problems. However, overdose mortality remains very high (more than 700 deceased per year), prevalence of both HIV and HCV are still high among injectors, and consequences of chronic liver diseases are emerging. In the last years the use of cocaine and associated problems have increased a lot. Nowadays there are more than 100,000 weekly cocaine users, 25.000 persons are annually treated from cocaine abuse or dependence, and cocaine has an important impact on medical emergency services, while its impact on mortality is unknown. Both cannabis use and related problems are increasing too (there are half a million of daily users). We propose to maintain and to strengthen harm reduction programs (MMT, syringe exchange, save-use and injection rooms, hepatitis A and B vaccination, etc.), to urgently develop specific strategies targeted to reduce overdose mortality and cocaine related problems, and to re-evaluate the effectiveness of preventive and supply control strategies. Las dramáticas consecuencias del consumo de heroína (principalmente inyectada) han marcado el fenómeno de las drogas ilegales en España en los últimos treinta años. Más de 300.000 personas han sido tratadas por dependencia de heroína, 20.000-25.000 han muerto por «sobredosis», 100.000 han adquirido el VIH mediante inyección de drogas y bastantes más se han infectado con los virus de la hepatitis. Algunas de estas consecuencias pueden atribuirse al retraso en la puesta en marcha de intervenciones efectivas, como los tratamientos de mantenimiento con metadona (TMM). Actualmente han descendido mucho estos problemas por el descenso del número de personas que se inyectan y el efecto de las intervenciones, principalmente los TMM. Sin embargo, la mortalidad por sobredosis sigue siendo muy alta (más de 700 muertes anuales), y entre los consumidores por vía intravenosa persiste una elevada prevalencia de VIH y hepatitis C, y están emergiendo las consecuencias de las hepatopatías crónicas. Paralelamente, ha aumentado espectacularmente el uso de la cocaína y con él los problemas que causa: hay más de 100.000 consumidores semanales, 25.000 personas tratadas anualmente por abuso o dependencia, y un impacto importante sobre los servicios médicos de urgencia. Su efecto sobre la mortalidad es desconocido. Están aumentando también el consumo y los problemas por cannabis (existe medio millón de consumidores diarios). Se propone mantener y reforzar los programas de reducción del daño (TMM, intercambio de jeringas, salas de consumo, vacunación de hepatitis A y B, etc.), desarrollar con urgencia estrategias específicas para reducir las muertes por sobredosis y los problemas por cocaína, y reevaluar la efectividad de las estrategias preventivas y de control de la oferta

Estimating high risk cannabis and opiate use in Ankara, Istanbul and Izmir

Aims. Information on high risk drug use in Turkey particularly at the regional level is lacking. The present analysis aims at estimating high risk cannabis (HRCU) and high risk opiate use (HROU) in the cities of Ankara, Istanbul and Izmir. Design and Methods. Capture-recapture (CRC) and multiplier methods (MM) were applied based on treatment and police data stratified by age and gender in the years 2009 and 2010. Case definitions refer to ICD-10 cannabis (F.12) and opiate (F.11) disorder diagnoses from out- and inpatient treatment records and illegal possession of these drugs as recorded by the police. Results. HRCU was estimated at 28,500 (8.5 per 1,000; 95%-CI: 7.3-10.3) and 33,400 (11.9 per 1,000; 95%-CI: 10.7-13.5) in Ankara and Izmir, respectively. Using multipliers based on CRC estimates for Izmir, HRCU in Istanbul was estimated up to 166,000 (18.0 per 1,000; range: 2.8-18.0). CRC estimates of HROU resulted in 4,800 (1.4 per 1,000; 95% CI: 0.9-1.9) in Ankara and multipliers based on these gave estimates up to 20,000 (2.2 per 1,000; range: 0.9-1-7) in Istanbul. HROU in Izmir was not estimated due to the low absolute numbers of opiate users. Discussion and Conclusions. While HRCU prevalence in both Ankara and Izmir was considerably lower in comparison to an estimate for Berlin, the rate for Istanbul was only slightly lower. Compared to the majority of European cities HROU in these three Turkish cities may be considered rather low

Cohort Study Methodology of the ITINERE Project on Heroin Users in Three Spanish Cities and Main Characteristics of the Participants

Fundamento: Los estudios de cohortes permiten monitorizar el impacto del uso de drogas sobre la salud, e identificar los factores condicionantes. El objetivo de este trabajo es describir la metodología y las características básicas de una cohorte de consumidores de heroína diseñada con este fin. Métodos: Participaron 991 jóvenes consumidores de heroína, seleccionados en la comunidad en Barcelona, Madrid y Sevilla, principalmente mediante nominación de otros participantes (39,7%) o de consumidores o exconsumidores no participantes (44,7%). Se administró un cuestionario con ordenador y se recogió una muestra de sangre en papel secante. También se registraron sus medidas antropométricas. Se remuneró a participantes y captadores. Se usaron métodos estadísticos uni y bivariados. Resultados: Un 42,4% había cambiado alguna vez de vía principal de administración de heroína, sobre todo hacia la inyección en Barcelona y hacia la vía pulmonar en Sevilla. Un 75,8% (Barcelona), 49,8% (Madrid), y 15,5% (Sevilla) se habían inyectado drogas en los últimos 12 meses. En Madrid y Sevilla un 96%-97% consumían la heroína sólo en forma de base, y en Barcelona predominaba la heroína-clorhidrato. Frecuentemente mezclaban heroína y cocaína en la misma dosis (generalmente cocaína-base en Madrid y Sevilla, y cocaína-clorhidrato en Barcelona). Conclusiones: Persisten importantes diferencias geográficas en la prevalencia de inyección de drogas y en los patrones de consumo de heroína y cocaína, lo que podría explicar la desigual distribución de algunos problemas de salud. Las dificultades para reunir la muestra prevista sugieren un descenso importante de la incidencia de consumo de heroína.La fuente principal de financiación del estudio fue la Fundación para Investigación y la Prevención del Sida en España, a través del proyecto FIPSE 3035/99. También se han recibido apoyos para investigaciones específicas de: Redes Temáticas de Investigación Cooperativa (C03-09 y G03-005), Fondo de Investigación Sanitaria (FIS 00/1017, FIS 01/0908), y Delegación del Gobierno para el Plan Nacional sobre Drogas.S