Deviant patterns of methylphenidate use in adults: a Danish nationwide registry-based drug utilization study

Core Concepts in Pharmacoepidemiology: Measures of drug utilization based on individual-level drug dispensing data

Background

Drug utilization studies are essential to facilitate rational drug use in the society.

Aim

In this review, we provide an overview of drug utilization measures that can be used with individual‐level drug dispensing data, referencing additional reading on the individual analysis. This is intended to serve as a primer for those new to drug utilization research and a shortlist from which researchers can identify useful analytical approaches when designing their drug utilization study.

Results and Discussion

We provide an overview of: (1) basic measures of drug utilization which are used to describe changes in drug use over time or compare drug use in different populations; (2) treatment adherence measures with specific focus on persistence and implementation; (3) how to measure drug combinations which is useful when assessing drug–drug interactions, concomitant treatment, and polypharmacy; (4) prescribing quality indicators and measures to assess variations in drug use which are useful tools to assess appropriate use of drugs; (5) proxies of prescription drug misuse and skewness in drug use; and (6) considerations when describing the characteristics of drug users or prescribers.

Early Detection of Prescription Drug Abuse Using Doctor Shopping Monitoring From Claims Databases: Illustration From the Experience of the French Addictovigilance Network

Opioid analgesics and maintenance treatments, benzodiazepines and z-drugs, and other sedatives and stimulants are increasingly being abused to induce psychoactive effects or alter the effects of other drugs, eventually leading to dependence. Awareness of prescription drug abuse has been increasing in the last two decades, and organizations such as the International Narcotics Control Board has predicted that, worldwide, prescription drug abuse may exceed the use of illicit drugs. Assessment of prescription drug abuse tackles an issue that is hidden by nature, which therefore requires a specific monitoring. The current best practice is to use multiple detection systems to assess prescription drug abuse by various populations in a timely, sensitive, and specific manner. In the early 2000's, we designed a method to detect and quantify doctor shopping for prescription drugs from the French National Health Data System, which is one of the world's largest claims database, and a first-class data source for pharmacoepidemiological studies. Doctor shopping is a well-known behavior that involves overlapping prescriptions from multiple prescribers for the same drug, to obtain higher doses than those prescribed by each prescriber on an individual basis. In addition, doctor shopping may play an important role in supplying the black market. The paper aims to review how doctor shopping monitoring can improve the early detection of prescription drug abuse within a multidimensional monitoring. The paper provides an in-depth overview of two decades of development and validation of the method as a complementary component of the multidimensional monitoring conducted by the French Addictovigilance Network. The process accounted for the relevant determinants of prescription drug abuse, such as pharmacological data (e.g., formulations and doses), chronological and geographical data (e.g., impact of measures and comparison between regions), and epidemiological and outcome data (e.g., profiles of patients and trajectories of care) for several pharmacological classes (e.g., opioids, benzodiazepines, antidepressants, and methylphenidate).

Doctor shopping for methylphenidate as a proxy for misuse and potential abuse in the 67 million inhabitants in France

Doctor shopping enables subjects to receive more than the prescribed dose out of any medical management, which suggests a search for high doses and makes doctor shopping a relevant proxy for misuse and potential abuse. Therefore, this study aimed to identify and characterize profiles of subjects with doctor-shopping behavior for methylphenidate in the entire French population. This study is a cross-sectional study of doctor-shopping behavior for methylphenidate in France, in 2016, using the Système national des données de santé, and accounting for overlapping prescriptions. Subjects who obtained >840 mg by doctor shopping were defined as subjects with heavy doctor-shopping behavior, and subjects who obtained >0 mg and ≤840 mg by doctor shopping were defined as subjects with light doctor-shopping behavior. A total of 63 739 subjects were included, and received 339.6 kg of methylphenidate. Among them, 216 (0.3%) subjects had heavy doctor-shopping behavior, and 313 (0.5%) subjects had light doctor-shopping behavior. Compared with subjects with light doctor-shopping behavior, subjects with heavy doctor-shopping behavior were older (64% of 30- to 49-year-old subjects vs. 77% of ≤17-year-old subjects; P < 0.001), received more concomitant dispensings of antipsychotics (37% vs. 26%; P = 0.008) and opioid maintenance treatments (50% vs. 6%; P < 0.001), and had more prescribers (4 [IQR = 2-5] vs. 2 [IQR = 2-3]; P < 0.001). In the French context where prescription and dispensing of methylphenidate are highly regulated and methylphenidate is much less used than in other countries, these results are a warning signal to avoid trivializing methylphenidate in adults.

Patterns and profiles of methylphenidate use both in children and adults

AIM

The aim of the present study was to characterize patterns of use of methylphenidate (MPH), a prescription stimulant medication recommended in the treatment of attention deficit hyperactivity disorder (ADHD) and of narcolepsy, in France, both in children and adults, over a 3-year period.

METHODS

Using the French General Health Insurance database, limited to two areas covering approximately 4 million individuals, we made up a cohort of incident MPH users between July 2010 and June 2013. Splitting them into distinct age groups (18-24, 25-49 and ≥50 years of age for adults and <6, 6-11 and 12-17 years of age for children), we established the characteristics of these populations at MPH initiation and during follow-up according to the duration of treatment, quantities dispensed and coprescription with central nervous system (CNS) drugs.

RESULTS

We included a cohort of 3534 incident users, involving 30 238 dispensings of MPH, leading to an annual rate of 29 incident users per 100 000 in 2013. Children (66% of new users) were characterized by long-term use of MPH with few comedications. The group of 25-49-year-old patients were dispensed MPH more frequently than other groups, had the highest mean dose and were more often coprescribed other CNS drugs. The ≥50 year-old group was more often coprescribed antidepressants and antiparkinsonian drugs.

CONCLUSIONS

Our pharmacoepidemiological study involving incident MPH users with a large number of characteristics showed different patterns of MPH use among children and adults. The results from the 25-49-year-old group suggested that MPH might be being used for medical conditions other than ADHD or narcolepsy in adults, and that it might be subject to misuse and/or abuse.

Use of attention-deficit/hyperactivity disorder medication among older adults in Denmark

AIMS

Knowledge on the use of attention-deficit/hyperactivity disorder (ADHD) medication among older adults is limited. We hypothesized that ADHD medication is used off-label in adults aged ≥50 years as part of palliative care in e.g. cancer patients. The aim of this study was to describe the use of ADHD medication among adults aged ≥50 years in Denmark.

METHODS

Using the Danish health registries, we identified new users ≥50 years of ADHD medication during 2000-2012. We estimated the annual incidence of ADHD medication use and ADHD diagnoses. We described new users of ADHD medication according to co-medication, comorbidities and assessed the 1-year cumulative mortality rate. A posthoc analysis allowed us to include new users until 2015.

RESULTS

We identified 6690 new users of ADHD medication from 2000 to 2012. From 2000 to 2015 we observed an increase in the incidence of ADHD medication use from 12.5 to 30.3 per 100 000 person-years. However, the incidence rate decreased from 2010 to 2015. Throughout the study period, the incidence rate of ADHD diagnoses was low (overall prevalence among new users ≤2%). Opioids were the most frequent comedication used (used by 54%), while cancer was the most frequent diagnosis preceding treatment (prevalence of 52%). The 1-year cumulative mortality was 50%, primarily driven by patients with a preceding cancer diagnosis.

CONCLUSION

There was an increase in the incidence of ADHD medication use in adults aged ≥50 years from 2000-2010 and a decreasing incidence from 2010-2015. Our results suggest that ADHD medication is used off-label in older adults as part of palliative care.