Exhibiting caution with use of big data: The case of amphetamine in Iceland's prescription registry.

BACKGROUND: Data from large electronic databases are increasingly used in epidemiological research, but golden standards for database validation remain elusive. The Prescription Registry (IPR) and the National Health Service (NHS) databases in Iceland have not undergone formal validation, and gross errors have repeatedly been found in Icelandic statistics on pharmaceuticals. In 2015, new amphetamine tablets entered the Icelandic market, but were withdrawn half a year later due to being substandard. Return of unused stocks provided knowledge of the exact number of tablets used and hence a case where quality of the data could be assessed. OBJECTIVE: A case study of the quality of statistics in a national database on pharmaceuticals. METHODS: Data on the sales of the substandard amphetamine were obtained from the Prescription Registry and the pharmaceuticals statistics database. Upon the revelation of discrepancies, explanations were sought from the respective institutions, the producer, and dose dispensing companies. RESULTS: The substandard amphetamine was available from 1.9.2015 until 15.3.2016. According to NHS, 73990 tablets were sold to consumers in that period, whereas IPR initially stated 82860 tablets to have been sold, correcting to 74796 upon being notified about errors. The producer stated 72811 tablets to have been sold, and agreed with the dose dispensing companies on sales to those. The producer's numbers were confirmed by the Medicines Agency. CONCLUSION: Over-registration in the IPR was 13.8% before correction, 2.7% after correction, and 1.6% in the NHS. This case provided a unique opportunity for external validation of sales data for pharmaceuticals in Iceland, revealing enormous quality problems. The case has implications regarding database integrity beyond Iceland.

No evidence of subgroups found in amphetamine consumers in Iran.

Amphetamine type substances are the second most commonly consumed illicit drug type and their use is an important contributor to the global burden of disease. This investigation set out to determine whether, similar to alcohol or nicotine addiction, subgroups of consumers can also be found in amphetamine addicts. 204 consumers of methamphetamine only (n = 50) or both methamphetamine and heroin (n = 154) have been investigated in Mashhad, Iran by means of "Lesch Alcoholism Typology". No significant differences in consumption pattern or age of onset have been found between the different types. Many subjects, however, reported symptoms of anxiety (n=78) or depression (n = 129) prior to drug use. These findings highlight the need for high quality epidemiological studies further addressing this issue.

Purity, adulteration and price of drugs bought on-line versus off-line in the Netherlands.

BACKGROUND AND AIMS: On-line drug markets flourish and consumers have high expectations of on-line quality and drug value. The aim of this study was to (i) describe on-line drug purchases and (ii) compare on-line with off-line purchased drugs regarding purity, adulteration and price. DESIGN: Comparison of laboratory analyses of 32 663 drug consumer samples (stimulants and hallucinogens) purchased between January 2013 and January 2016, 928 of which were bought on-line. SETTING: The Netherlands. MEASUREMENTS: Primary outcome measures were (i) the percentage of samples purchased on-line and (ii) the chemical purity of powders (or dosage per tablet); adulteration; and the price per gram, blotter or tablet of drugs bought on-line compared with drugs bought off-line. FINDINGS: The proportion of drug samples purchased on-line increased from 1.4% in 2013 to 4.1% in 2015. The frequency varied widely, from a maximum of 6% for controlled, traditional substances [ecstasy tablets, 3,4-methylenedioxy-methamphetamine (MDMA) powder, amphetamine powder, cocaine powder, 4-bromo-2,5-dimethoxyphenethylamine (2C-B) and lysergic acid diethylamide (LSD)] to more than a third for new psychoactive substances (NPS) [4-fluoroamphetamine (4-FA), 5/6-(2-aminopropyl)benzofuran (5/6-APB) and methoxetamine (MXE)]. There were no large differences in drug purity, yet small but statistically significant differences were found for 4-FA (on-line 59% versus off-line 52% purity for 4-FA on average, P = 0.001), MDMA powders (45 versus 61% purity for MDMA, P = 0.02), 2C-B tablets (21 versus 10 mg 2C-B/tablet dosage, P = 0.49) and ecstasy tablets (131 versus 121 mg MDMA/tablet dosage, P = 0.05). The proportion of adulterated samples purchased on-line and off-line did not differ, except for 4-FA powder, being less adulterated on-line (χ2  = 8.3; P < 0.02). Drug prices were mainly higher on-line, ranging for various drugs from 10 to 23% higher than that of drugs purchased off-line (six of 10 substances: P < 0.05). CONCLUSIONS: Dutch drug users increasingly purchase drugs on-line: new psychoactive substances in particular. Purity and adulteration do not vary considerably between drugs purchased on-line and off-line for most substances, while on-line prices are mostly higher than off-line prices.

ADHD medication use, adherence, persistence and cost among Texas Medicaid children.

OBJECTIVES: (1) Describe ADHD medication use, adherence and persistence. (2) Determine factors (e.g., medication type, demographics, concomitant medication use) associated with ADHD medication adherence and persistence. (3) Compare ADHD medication costs. METHODS: Continuously enrolled Texas Medicaid children (3-18 years) with ≥ 2 ADHD prescription claims (July 2002-December 2008) were included. Prescription claims were grouped by medication type (i.e., immediate-release, extended-release, prodrug, non-stimulant); medication class (i.e., stimulant, non-stimulant); and duration of action (i.e., long-acting, short-acting). Adherence, using medication possession ratio, was measured continuously and dichotomously (80% cut-off). Persistence was days of continuous therapy without a 30-day gap and medication costs were reimbursement amount paid to dispensing pharmacies. RESULTS: The study sample (n = 62,789) was primarily 6-12 years (61.7%) and male (69.2%). The majority of the subjects were prescribed extended-release agents (70.3%), stimulant agents (86.4%), and long-acting agents (84.5%). Adherence and persistence (adherence mean ± SD; adherence dichotomous; persistence mean ± SD) varied among medication type and was highest for non-stimulants (52.5 ± 30.9; 25.8%; 153.3 ± 124.3), followed by extended-release stimulants (52.1 ± 30.2; 24.1%; 143.7 ± 120.8), prodrug stimulants (47.6 ± 30.9; 21.1%; 113.3 ± 100.5) and immediate-release stimulants (37.2 ± 27.1; 9.8%; 95.4 ± 92.6). Logistic regression showed immediate-release stimulant users were 67% less adherent than non-stimulant users (p < 0.0001) and linear regression showed immediate-release, extended-release and long-acting users (p < 0.0001) were significantly less persistent than non-stimulant users. Females, increase in total number of medications, and comorbid medications were associated with better adherence and persistence. Non-stimulant agents ($4.04 ± $2.15) had the highest mean medication cost per patient per day and immediate-release stimulants had the lowest ($1.24 ± $0.97). CONCLUSIONS: ADHD medication adherence and persistence was suboptimal. Although there was no difference in adherence between long-acting stimulant and non-stimulant users, non-stimulant users were more persistent compared to stimulant users. This study was limited due to the use of retrospective prescription claims data, which cannot capture actual patient use patterns, ICD-9 diagnoses, family history and support, or side effect profiles. Because ADHD can be effectively treated with pharmacotherapy, providers should be proactive in identifying patients with poor adherence and intervene to address barriers to medication adherence and persistence.

The relationship of quality and price of the psychostimulants cocaine and amphetamine with health care outcomes.

A major component of the illicit drug market can be subcategorized as the psychostimulant drug market, with cocaine and amphetamine as popular constituents. In The Netherlands, an increase in both health care outcomes addiction treatment and hospital admissions was noted for both amphetamine and cocaine throughout a period of 17 years (1992-2008). Both cocaine price and quality showed a decrease in The Netherlands during the studied period. We used time-series regression analysis to investigate whether price or quality of the drugs were associated with health care outcomes. Drug seizures were also added to the time-series regressions in order to check for possible effects of drug availability and supply. Price and quality of cocaine were strongly associated with health care outcomes of addiction treatment and hospital admissions. Price of amphetamine also showed a decrease during these 17 years, but was associated with an increase in addiction treatment only. Other amphetamine market variables did not show any relationship with the health care outcomes. It could be stated that following basic market logics does not apply equally to all psychostimulants of abuse. Other factors might play a role, such as the addictiveness or desirability of a specific drug in question. This finding is supportive of the dynamics of the illicit psychostimulant market affecting actual use and thereby health care outcomes.

The effects of perceived quality on the behavioural economics of alcohol, amphetamine, cannabis, cocaine, and ecstasy purchases.

Previous research has indicated that non-dependent polydrug users are willing to pay more money to buy good quality drugs as their income increased. This study sought to examine whether altering the perceived quality of controlled drugs would affect drug purchases if the monetary price remained fixed. A random sample of 80 polydrug users were recruited. All participants were administered an anonymous questionnaire consisting of the Drug Abuse Screening Test for Adolescents (DAST-A), the Severity of Dependence Scale for cannabis (SDS), the Alcohol Use Disorders Identification Test (AUDIT), the Hospital Anxiety and Depression Scale (HADS), and questions about their drug use. Participants then completed a simulation of controlled drug purchases where the price of alcohol, amphetamine, cannabis, cocaine, and ecstasy remained the same but their perceived quality changed (i.e. unit price increased as the perceived quality decreased). The demand for alcohol was quality inelastic and alcohol quality had no effects on the purchase of any other controlled drug. Demand for cannabis was quality elastic and alcohol substituted for cannabis as its unit price increased. Demand for cocaine was quality elastic and alcohol, cannabis, and ecstasy substituted for cocaine as its unit price increased. Demand for ecstasy was quality elastic and alcohol and cocaine both substituted for ecstasy as its unit price increased. These results suggest that perceived quality influences the demand for controlled drugs and that monitoring the perceived quality of controlled drugs may provide a warning of potential public health problems in the near future.

The effects of price and perceived quality on the behavioural economics of alcohol, amphetamine, cannabis, cocaine, and ecstasy purchases.

Behavioural economic models of substance use describe the relationship between changes in unit price and consumption. However, these models rarely take account of the perceived quality (i.e. potency) of controlled drugs. Therefore we investigated the effects of both price and quality on the decision to purchase controlled drugs by polysubstance misusers. Forty current polysubstance misusers (29 males, 11 females; mean age 23.8) were recruited into the study. Participants were asked to hypothetically purchase drugs from a price list of alcohol, amphetamine, cannabis, cocaine and ecstasy at different levels of quality and price (i.e. better quality drugs cost more money). The disposable income available for those purchases was systematically varied in order to determine the impact of income on the decision to purchase drugs. Demand for both normal and strong alcohol was income inelastic. Demand for both poor and average quality cannabis and ecstasy was income inelastic, but demand for good quality cannabis and ecstasy was income elastic. The demand for poor quality cocaine was income inelastic, with the demand for both average and good quality cocaine being income elastic. Participants reported too few purchases of amphetamine, which precluded behavioural economic analysis. These results suggest that, like other goods, controlled drugs are purchased based upon the consumer's interpretations of their relative value. Therefore, it is probable that the purchase and subsequent use of controlled drugs by polysubstance misusers will be heavily influenced by the economic environment.

Identification and quantification of change in Australian illicit drug markets.

BACKGROUND: In early 2001 Australia experienced a sudden reduction in the availability of heroin which had widespread effects on illicit drug markets across the country. The consequences of this event, commonly referred to as the Australian 'heroin shortage', have been extensively studied and there has been considerable debate as to the causes of the shortage and its implications for drug policy. This paper aims to investigate the presence of these epidemic patterns, to quantify the scale over which they occur and to estimate the relative importance of the 'heroin shortage' and any epidemic patterns in the drug markets. METHOD: Key indicator data series from the New South Wales illicit drug market were analysed using the statistical methods Principal Component Analysis and SiZer. RESULTS: The 'heroin shortage' represents the single most important source of variation in this illicit drug market. Furthermore the size of the effect of the heroin shortage is more than three times that evidenced by long-term 'epidemic' patterns. CONCLUSION: The 'heroin shortage' was unlikely to have been a simple correction at the end of a long period of reduced heroin availability, and represents a separate non-random shock which strongly affected the markets.

A behavioural economic analysis of alcohol, amphetamine, cocaine and ecstasy purchases by polysubstance misusers.

Behavioural economic models of substance choice describe the relationship between changes in unit price and consumption. As the majority of UK non-dependent substance misusers are polysubstance misusers, we investigated the influence of price upon hypothetical purchases of alcohol, amphetamine, cocaine and ecstasy. Forty-three current polysubstance misusers (25 males, 18 females; mean age 21.3 +/- 2.8) were recruited into the study. As the price of alcohol rose, demand was inelastic. Amphetamine was a substitute for alcohol, cocaine was a compliment drug and ecstasy was independent. Demand for amphetamine was elastic as its price rose, but only alcohol was identified as a substitute drug and other drug purchases were independent of amphetamine price. As the price of cocaine increased, demand was elastic. Alcohol and ecstasy were substitute drugs but amphetamine purchase was independent, indicating asymmetrical substitution of alcohol and cocaine. Finally, demand for ecstasy was also elastic, but only cocaine substituted as ecstasy price rose. These results extend previous findings in substance dependent populations using behavioural economic models and support the opinion that purchasing substances is a complex process, involving both socio-economic and psychopharmacological factors. Whilst subjects expressed a preference for ecstasy, these behavioural findings indicated that alcohol was their drug of choice when economic considerations were brought into play. Self-reported drug preference, although facilitating between subjects experimental design, may therefore not accurately represent real world polysubstance misuse.