Ethical considerations for drug abuse epidemiological research

The mortality and morbidity caused by alcohol, tobacco and illicit drug misuse represents a significant public health burden (Ezzati et al., 2002). A key part of the public health response is the collection of epidemiological and social science data to define at-risk populations to identify opportunities for intervention and to evaluate the effectiveness of policies in preventing or treating drug misuse and drug-related harm. The systematic use of epidemiological and social science research methods to study illicit drug use is barely 40 years old in the United States and United Kingdom, which have pioneered this approach. Because of the sensitive nature of epidemiological research on illicit drug use a unique set of ethical challenges need to be explicitly addressed by the field. Although ethics guidelines have been proposed (Council for International Organizations of Medical Sciences, 1991), scholarship on the ethics of epidemiology is scant, and consensus on core values not yet achieved (Coughlin, 2000).

Illicit Opiate Abuse

Illicit opiate use, especially injected drugs, contributes to premature mortality and morbidity in many developed and developing societies. The economic costs of illicit drug use are substantial. Fatal overdoses and HIV/AIDS resulting from sharing dirty needles and injecting equipment are major contributors to mortality and morbidity. Illicit opioid use accounted for 0.7 percent of global disability–adjusted life years in 2000. An estimated 15.3 million people, or 0.4 percent of the world population ages 15 to 64, used illicit opioids in 2002, with more than half using heroin and the rest using opium or diverted pharmaceuticals such as buprenorphine, methadone, or morphine. The most popular interventions for illicit opioid dependence in many developed societies have been law enforcement efforts to interdict the drug supply and enforce legal sanctions against drug use. One consequence has been that illicit opioid users have been exposed to the least effective intervention: imprisonment for drug or property offenses. The most effective intervention to reduce blood–borne virus infection resulting from illicit drug injections is provision of clean injecting equipment to users. This intervention has been widely supported in developed countries, but less so in developing countries. In addition, vaccinations are effective against hepatitis B. In treatment settings, the most popular interventions have been detoxification and drug–free treatment, which has proven the least productive in retaining opioid–dependent people in treatment. Opioid agonists have a niche role in treatment of opioid dependence, especially if their efficacy improves with development of long–acting injectable forms of the drug.

Drug use evaluation of ipratropium bromide at two tertiary referral hospitals in Brisbane.

Objective: To assess the appropriateness of ipratropium bromide prescribing in two tertiary referral hospitals. Method: Criteria for optimal use were developed based on current literature and modified after consultation with respiratory physicians and clinical pharmacists. A prospective review of prescribing was performed over a 2-month period to assess conformity to these criteria. Results: Information was collected from 84 patients; 5% were receiving inhalers and 96% nebuliser therapy (one patient used both). 77% of patients (n = 65) had a principal diagnosis of chronic obstructive pulmonary disease, 14% (n = 12) asthma and 8% (n = 7) had neither diagnosis. 75% of patients were using ipratropium outside the guidelines. The major areas where the guidelines were not met were a lack of therapeutic justification, use of inappropriate doses, and use of an inappropriate delivery device. Feedback and educational interventions were designed and delivered based on the data obtained. Conclusions: There was widespread use of ipratropium outside the developed guidelines. Interventions in specific areas could lead to significant improvements in the use of this high cost drug

Estimating Two-Stage Models for Genetic Influences on Alcohol, Tobacco or Drug Use Initiation and Dependence Vulnerability in Twin and Family Data

Genetic research on risk of alcohol, tobacco or drug dependence must make allowance for the partial overlap of risk-factors for initiation of use, and risk-factors for dependence or other outcomes in users. Except in the extreme cases where genetic and environmental risk-factors for initiation and dependence overlap completely or are uncorrelated, there is no consensus about how best to estimate the magnitude of genetic or environmental correlations between Initiation and Dependence in twin and family data. We explore by computer simulation the biases to estimates of genetic and environmental parameters caused by model misspecification when Initiation can only be defined as a binary variable. For plausible simulated parameter values, the two-stage genetic models that we consider yield estimates of genetic and environmental variances for Dependence that, although biased, are not very discrepant from the true values. However, estimates of genetic (or environmental) correlations between Initiation and Dependence may be seriously biased, and may differ markedly under different two-stage models. Such estimates may have little credibility unless external data favor selection of one particular model. These problems can be avoided if Initiation can be assessed as a multiple-category variable (e.g. never versus early-onset versus later onset user), with at least two categories measurable in users at risk for dependence. Under these conditions, under certain distributional assumptions., recovery of simulated genetic and environmental correlations becomes possible, Illustrative application of the model to Australian twin data on smoking confirmed substantial heritability of smoking persistence (42%) with minimal overlap with genetic influences on initiation.

Escalation of Drug Use in Early-Onset Cannabis Users vs Co-twin Controls

Context Previous studies have reported that early initiation of cannabis (marijuana) use is a significant risk factor for other drug use and drug-related problems. Objective To examine whether the association between early cannabis use and subsequent progression to use of other drugs and drug abuse/dependence persists after controlling for genetic and shared environmental influences. Design Cross-sectional survey conducted in 1996-2000 among an Australian national volunteer sample of 311 young adult (median age, 30 years) monozygotic and dizygotic same-sex twin pairs discordant for early cannabis use (before age 17 years). Main Outcome Measures Self-reported subsequent nonmedical use of prescription sedatives, hallucinogens, cocaine/other stimulants, and opioids; abuse or dependence on these drugs (including cannabis abuse/dependence); and alcohol dependence. Results Individuals who used cannabis by age 17 years had odds of other drug use, alcohol dependence, and drug abuse/dependence that were 2.1 to 5.2 times higher than those of their co-twin, who did not use cannabis before age 17 years. Controlling for known risk factors (early-onset alcohol or tobacco use, parental conflict/separation, childhood sexual abuse, conduct disorder, major depression, and social anxiety) had only negligible effects on these results. These associations did not differ significantly between monozygotic and dizygotic twins. Conclusions Associations between early cannabis use and later drug use and abuse/dependence cannot solely be explained by common predisposing genetic or shared environmental factors. The association may arise from the effects of the peer and social context within which cannabis is used and obtained. In particular, early access to and use of cannabis may reduce perceived barriers against the use of other illegal drugs and provide access to these drugs.

Audit of selective and non-selective non-steroidal anti-inflammatory drug use in rural general practice

Aim: To identify the demographics and risk factors in a selected patient population prescribed non-selective and cyclo-oxygenase-2 (COX- 2) selective non-steroidal anti-inflammatory drugs (NSAIDs). Method: A structured clinical self-audit form was distributed in January to March 2001 to 155 interested general practitioners (GPs) in rural Queensland. Results: Seventy one GPs participated in the audit and contributed 1417 patient records - 790 patients had received nonselective NSAIDs and 627 had received COX-2 inhibitors (celecoxib or rofecoxib). Patients who received COX-2 inhibitors were significantly older, more likely to have clinically important concomitant illness, and more likely to be taking medication known to interact with NSAIDs. They were also twice as likely to have two or more risk factors for adverse effects. The most common reasons for switching from an NSAID to a COX-2 inhibitor were reported to be a previous side effect from an NSAID (primarily related to gastrointestinal effects) or the doctor's perception of the superior efficacy of COX-2 inhibitor therapy. Conclusions: This study has shown that COX-2 inhibitors were used in a distinctly different patient population compared to non-selective NSAIDs. There were significant variations in the demographics and number of risk factors - for example, cardiovascular and renal - between the two identified populations. These differences may be due to doctors selecting COX-2 inhibitors for patients at high risk of gastrointestinal complications. However, the prescribing pattern may also be partly due to misconceptions about the relative safety and efficacy of COX-2 inhibitor drugs.