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Biomedical subjects

Benedikt Fischer

Publications and source records attributed to Benedikt Fischer.

At least 19 recordsLinked to original sources
PubMed2007

Multiple viral hepatitis in injection drug users and associated risk factors.

BACKGROUND: While infections due to hepatitis B virus (HBV) and hepatitis C virus (HCV) have been well-studied in injection drug users (IDUs), hepatitis A virus (HAV) infection and coinfection with multiple hepatitis viruses have received less attention. METHODS: Hepatitis serology as well as sociodemographic and drug-related parameters were explored in patients (n = 1512) admitted for opiate detoxification. RESULTS: Antibodies to HAV were positive in 57.7%, to HBV in 53.0%, and to HCV in 75.0% of the sample. Lack of any hepatic marker was reported in 11.2%; one marker was positive in 24.7%; two markers were positive in 31.2%; and all markers were positive in 32.9%. In patients with one positive marker, 58.8% had had exposure to HCV, and 27% had exposure to HAV. In patients with two positive markers, 46.7% were HAV/HCV and 41.8% HBV/HCV antibody positive. Presence of HBV and HCV antibodies was associated with older age, longer duration of (i.v.) heroin use, and a higher number of rehabilitation treatment episodes (anova), current coconsumption of cocaine was associated with presence of antibodies to either HAV, HBV, and HCV. CONCLUSIONS: Coinfection with hepatic viruses is highly relevant in IDUs, although HAV does not necessarily share the same risk factors relevant for HBV or HCV transmission. The need for outreach vaccination programs is emphasized for HAV and HBV in the target population. Primary prevention should be implemented before initiation or at early stages of a drug career. Epidemiology and transmission of HAV in IDUs requires further research.

Adult↗
PubMed2006

Using latent class analysis (LCA) to analyze patterns of drug use in a population of illegal opioid users.

BACKGROUND: The objective of this paper is to empirically determine a categorization of illegal opioid users in Canada in order to describe and analyze drug use patterns within this population. METHODS: Drug use patterns of 679 eligible illegal opioid users outside treatment from the OPICAN study, a pan-Canadian cohort (recruited March to December, 2002) involving the cities of Toronto, Montreal, Vancouver, Edmonton and Quebec City, were empirically examined using latent class analysis. These latent classes were then further analyzed for associations using chi-square and t-test statistics. FINDINGS: The opioid and other drug user sample surveyed were categorized into three latent classes. Class 1 (N=256) was characterized by the use of Tylenol 3 and benzodiazepines along with high levels of depression and self-reported pain. Class 2 (N=68) was described by the non-injection use of both heroin and crack while having a high level of homelessness. Class 3 (N=344) was shown to consist of injection drug users of heroin and cocaine exhibiting the highest levels of HIV and Hepatitis C infections amongst the classes. CONCLUSIONS: Using latent class analysis we found distinct patterns of drug use amongst illegal opioid users differing in terms of type of drugs co-used, social context, and co-morbid pathologies. These data may be useful as the empirical basis for the planning of specific prevention and treatment interventions.

Acetaminophen↗
PubMed2006

Treatment for hepatitis C virus and cannabis use in illicit drug user patients: implications and questions.

Illicit drug users are the primary risk group for HCV transmission, and will form the largest HCV treatment population for years to come. Sylvestre et al.'s study suggests that cannabis use may benefit treatment retention and outcomes in illicit drug users undergoing HCV treatment. In fact, there is substantial evidence that cannabis use may help address key challenges faced by drug users in HCV treatment (e.g., nausea, depression), especially when such treatment occurs in the context of methadone maintenance treatment which may amplify these consequences. While further research is required on the biological and clinical aspects of the benefits of cannabis use for HCV treatment, and the effectiveness of cannabis use for HCV treatment needs to be explored in larger study populations, we advocate that in the interim existing barriers to cannabis use are removed for drug users undergoing HCV treatment until the conclusive empirical basis for evidence-based guidance is available.

Antiviral Agents↗
PubMed2006

Crack across Canada: Comparing crack users and crack non-users in a Canadian multi-city cohort of illicit opioid users.

AIMS: To examine possible differences between crack users and crack non-users across Canada. DESIGN: Cohort study of illicit opioid and other drug users in five cities across Canada. SETTING: Vancouver, Edmonton, Toronto, Montreal and Quebec City, Canada. PARTICIPANTS: Regular illicit opioid and other street drug users not in treatment at time of assessment. MEASUREMENTS: Participants (n = 677) were assessed at baseline (2002) by way of an interviewer-administered questionnaire, a psychiatric diagnostic instrument (Composite International Diagnostic Interview), and salivary antibody tests for infectious disease. FINDINGS: Approximately half the sample had used crack in the past 30 days, although prevalence rates differed strongly between study sites. When examined by discriminant analysis, crack users in the study population were more likely to have: no permanent housing, have illegal and sex work income, indicate physical health problems and hepatitis C virus (HCV) antibodies, use walk-in clinics, use heroin and to have been arrested and in detention (in past year). They were less likely to report depressive symptoms, and use Dilaudid (hydromorphone) and alcohol. CONCLUSION: These results illustrate crack users' pronounced social marginalization (as expressed by homelessness and high involvement in illegal activities) as well as extensive health problems compared to non-crack users in the Canadian context. The development of targeted interventions-addressing the dynamics of social marginalization-of this population is urgently needed.

Adult↗
PubMed2006

Determinants of health-related quality of life of opiate users at entry to low-threshold methadone programs.

OBJECTIVE: The aim of this study was to conduct an exploratory analysis of factors associated with poor health-related quality of life (HRQOL) among opiate users at entry to low-threshold methadone treatment. METHODS: The SF-36 questionnaire was administered to 145 opiate users at enrollment into low-threshold methadone maintenance programs. ANOVA and correlational analyses were performed to investigate the determinants of poor physical and mental composite summary scales (PCS and MCS) of the SF-36 among opiate users. Stepwise regression methods were also employed to fit PCS and MCS multivariate models. RESULTS: Age, employment status, chronic medical conditions, hospitalization, emotional abuse, sexual abuse and age at first injection episode were significantly associated with PCS. Mental health problems, sexual abuse, physical abuse, the use of sedatives, the use of cocaine, the number of days of cocaine use, sedative use and multiple substance use in the past month were significantly associated with MCS. The variances in the MCS and PCS were not readily explained by any one factor. CONCLUSION: The multiplicity of factors influencing HRQOL of opiate users suggests the need for a range of services within the context of a methadone program, addressing primary medical care needs as well as treatment for both mental health problems and abuse issues.

Adolescent↗
PubMed2006

Comparing injecting and non-injecting illicit opioid users in a multisite Canadian sample (OPICAN Cohort).

Illicit opioid use in Canada and elsewhere increasingly involves a variety of opioids and non-injection routes of administration. Injection and non-injection opioid users tend to differ in various key characteristics. From a public health perspective, non-injection routes of opioid use tend to be less harmful due to lesser morbidity and mortality risks. Our study compared current injectors (80%) and non-injectors (20%) in a multi-site sample of regular illicit opioid users from across Canada ('OPICAN' study). In bivariate analysis, injectors and non-injectors differed by prevalence in social and health characteristics as well as drug use. Logistic regression analysis identified city, drug use, housing status and mental health problems as independent predictors of injection status. Further analysis revealed that the majority of current non-injectors had an injection history. Our results reinforce the need to explore potential interventions aimed at preventing the transition from non-injectors to injecting, or facilitating the transition of injectors to non-injecting, as initiated in several other contexts.

Adult↗
PubMed2006

Illicit opioid use and its key characteristics: a select overview and evidence from a Canadian multisite cohort of illicit opioid users (OPICAN).

OBJECTIVES: To summarize key characteristics and consequences of illicit opioid use from the literature and to present corresponding data from a multisite sample of illicit opioid users in 5 Canadian cities (OPICAN study). METHOD: We undertook an overview of recent literature from North America, Australia, and Europe. We obtained data from the multicity OPICAN cohort study, which consisted of an interviewer-administered questionnaire, a standardized mental health instrument (the Composite International Diagnostic Interview Short Form for depression), and saliva-antibody tests for infectious disease (that is, HIV and hepatitis C virus). The baseline sample (n=679) was collected in 2002. RESULTS: Illicit opioid use in Canada and elsewhere is becoming increasingly heterogeneous in terms of opioid drugs used, with heroin playing an increasingly minor role; further, it predominantly occurs in a context of polydrug use (for example, cocaine-crack or benzodiazepines). Large proportions of illicit opioid users have physical and (or) mental health comorbidities, including infectious disease and (or) depression, and therefore require integrated interventions. Finally, morbidity risks among illicit opioid users are often predicted by social marginalization factors, for example, housing status or involvement in CONCLUSIONS: Given the epidemiologic profile and high disease burden associated with contemporary forms of illicit opioid use, more effective treatment approaches are urgently needed in Canada and elsewhere. Specifically, treatment must adjust to the extensive polysubstance use realities, yet it must also more effectively address the complex physical and (or) mental health comorbidities presented by this high-risk population.

Canada↗
PubMed2005

Feasibility and outcome of HCV treatment in a Canadian federal prison population.

We assessed feasibility and outcome of hepatitis C virus (HCV) treatment in male correctional inmates in British Columbia, Canada. We reviewed the medical charts of 114 treated inmates; 80 had complete data for treatment outcome. Approximately 4 of 5 inmates completed treatment (78.8%); 66.3% achieved sustained virological response. Those who completed treatment, those with injection drug use as a risk factor, and those with genotypes 2 and 3 were significantly more likely to achieve sustained virological response. HCV treatment in correctional inmates is feasible and effective.

Adult↗
PubMed2005

Illicit opioid use in Canada: comparing social, health, and drug use characteristics of untreated users in five cities (OPICAN study).

Most of the estimated 125,000 injection drug users (IDUs) in Canada use illicit opioids and are outside treatment (i.e., methadone maintenance treatment). Empirical data suggest that illicit opioid users outside treatment are characterized by various health and social problem characteristics, including polydrug use, physical and mental morbidity, social marginalization, and crime. Although required for evidence-based programming, systematic information on this specific substance-user population is sparse in Canada to date. This article presents and compares key characteristics of population of illicit opioid users outside treatment in five cities across Canada (OPICAN cohort). Overall, the majority of OPICAN participants regularly used both a variety of illicit opioids and cocaine or crack, reported physical and mental health (e.g., mood disorder) problems, lacked permanent housing, were involved in crime, and had their "ideal" treatment not available to them. However, key local sample differences were shown, including patterns of heroin versus prescription opioid use and levels of additional cocaine versus crack use as well as indicators of social marginalization. Illicit opioid user population across Canada differ on key social, health, and drug use indicators that are crucial for interventions and are often demonstrated between larger and smaller city sites. Differentiated interventions are required.

Adult↗
PubMed2005

Factors predicting 2-year retention in methadone maintenance treatment for opioid dependence.

Factors predicting 2-year retention in methadone maintenance and the impact of repeat treatment episodes on retention are examined. Data (n=9555 episodes) were drawn from a population-based treatment registry and analyses were performed using episode-weighted data. We estimated a binary logistic regression model with a duration of 730 days or greater as the dependent variable. The odds of remaining in treatment for 730 days or more increase with age and vary by region and provider type, but decrease with increasing number of treatment episodes. In comparison with other studies, these analyses show much higher rates of retention in methadone treatment but suggest that repeat episodes may not be as beneficial as existing research suggests.

Adult↗
PubMed2005

Patterns of opioid and cocaine co-use: a descriptive study in a Canadian sample of untreated opioid-dependent individuals.

This study examined prevalence and patterns of co-use of opioids and cocaine in regular users of illicit opioids (N = 729) recruited from 5 Canadian cities. Fifty-seven percent (n = 417) reported having used both opioids and cocaine in the month and week preceding the interview; of these, 73% (n = 304) were able to identify a typical pattern of daily co-use. In a typical day, injectors of opioids and cocaine (n = 119) and injectors of opioids who inhaled cocaine (n = 111) showed stable opioid use but variable cocaine use, which peaked at 21 hr. Overall, 30% of the individuals used both drugs exclusively in a sequential fashion, 35% reported taking opioids and cocaine within the same hour, and 35% reported taking them together at the same time or mixing them. These findings indicate that different individuals display different patterns of opioids and cocaine co-use.

Adolescent↗
PubMed2005

Eyes wide shut?--A conceptual and empirical critique of methadone maintenance treatment.

BACKGROUND: Methadone maintenance treatment (MMT) has been the 'gold standard' pharmacotherapy treatment for illicit opioid dependence for over 30 years. It has been widely evaluated, and is generally claimed to be 'effective'. METHODS: The objective of this paper is to review the rationale of MMT as an intervention for a biomedical disorder with primary social objectives as well as the methodological quality and evidence of MMT outcome research. Data sources included opioid dependence treatment practice, review and outcome research literature (1965-2001) in the form of peer-reviewed articles, books, monographs and reports that are preeminently cited and reviewed international studies on MMT. RESULTS/DATA SYNTHESIS: Rigorous and appropriate evaluation (i.e., RCTs, intent-to-treat, patient-centered) methods in MMT evaluations are rare. Evidence of MMT's effectiveness on primary treatment objectives is mixed and appears to be largely partial and short-term. Positive outcomes may be the result of selection effects of compliant patients and loss in proportion when more rigorous standards of analysis are applied. CONCLUSIONS: The quality of existing MMT research, and evidence for its general effectiveness are limited. Key concepts of self-medication and psychiatric comorbidity are largely ignored in MMT treatment and research frameworks, although they may serve to explain MMT's limited treatment success. Emerging new opioid pharmacotherapies require the fundamental review of the existing MMT paradigm as well as the application of rigorous and appropriate evaluation methods for future treatment.

Comorbidity↗
PubMed2005

A generic concept for the implementation of medical image retrieval systems.

This work presents mechanisms to support the development and installation of content-based image retrieval in medical applications (IRMA). A strict separation of feature extraction, feature storage, feature comparison, and the user interfaces is suggested. The concept and implementation of a system following these guidelines is described. The system allows to reuse implemented components in different retrieval algorithms, which improves software quality, shortens the development cycle for applications, and allows to establish standardized end-user interfaces.

Algorithms↗
PubMed2004

Determinants of overdose incidents among illicit opioid users in 5 Canadian cities.

BACKGROUND: Drug overdose is a major cause of death and illness among illicit drug users. Previous research has indicated that most illicit drug users experience nonfatal overdoses and has suggested a variety of factors that are associated with risk of overdose. In this study, we examined the occurrence of and the factors associated with nonfatal overdoses within a Canadian sample of illicit opioid users not enrolled in treatment at the time of study recruitment. METHODS: Interviewers used a standard questionnaire to collect data on sociodemographic characteristics, drug use, health and health care, experience in the criminal justice system and treatment for drug problems; they also performed standard assessments for mental health and infectious disease. The association between overdose and sociodemographic and drug-use factors was examined with chi(2) and t test analyses; marginally significant variables were examined with logistic regression to determine independent effects. RESULTS: A total of 679 subjects were interviewed; 651 provided answers sufficient for this analysis. One hundred and twelve (17.2%) of the 651 respondents reported an overdose episode in the previous 6 months. In the logistic regression analysis (after adjustment for sociodemographic factors), homelessness, noninjection use of hydromorphone in the past 30 days and involvement in drug treatment in the past 12 months were predictors of overdose (p < 0.05). INTERPRETATION: Overdose poses a considerable health risk for illicit opioid users. We found that a diverse set of factors was associated with overdose episodes. Prevention efforts will likely be more effective if they can be directed to specific causal factors.

Adult↗