Prioritizing children's medicines for research: a pharmaco-epidemiological study of antiepileptic drugs

Indications and prescribing patterns of antiseizure medications in children in New Zealand

AIM

To determine indications and prescribing patterns for antiseizure medications (ASMs) in children by age, sex, and socioeconomic status.

METHOD

This retrospective study searched the New Zealand database of ASM prescriptions dispensed to individuals aged 18 years or under during 2015 in three regions of New Zealand (48% paediatric population). Medical records were reviewed by a paediatric neurologist for indication. ASMs were grouped into old or new (1993 onwards).

RESULTS

In total, 2594 children (0 to 18 years, mean age 11 years 2 months, median 12 years; 51% male) were dispensed 3557 ASMs for seizures (76%), pain (6%), headache (5%), mental health (3%), and movement disorders (2%). After 10 years of age, lamotrigine was more likely and valproate less likely to be prescribed in females than males. No sex difference was observed for valproate prescriptions for non-seizure indications. Topiramate prescriptions increased in adolescent females. Prescriptions for non-seizure indications increased from 7% in children aged 6 years or under to 31% in 16- to 18-year-olds. The proportion of children receiving a new ASM compared to an old ASM was greater in children from higher than lower socioeconomic areas.

INTERPRETATION

Our results highlight a need for focused ASM teratogenicity messaging to clinicians prescribing ASMs for non-seizure indications. In addition, to improve equity of epilepsy care, it is critical for health policies to consider socioeconomic factors that impact on ASM prescribing.

Pharmacovigilance in Pediatric Patients with Epilepsy Using Antiepileptic Drugs

Objective: To investigate the occurrence of adverse effects of antiepileptic drugs (AEDs) in pediatric epileptic patients on mono- or polytherapy. Method: We evaluated eighty consecutive patients that met the following inclusion criteria: aged ≤18 years; diagnosed with epilepsy for at least one year; a stable dose of AED for at least three months; verbal consent to participation in the study. Patients were asked if they had experienced any adverse drug reaction (ADR) related to the AED. Afterward, regardless of the answer, they were interviewed based on a detailed semi-structured questionnaire about the presence of ADRs associated with the AED. The data were analyzed regarding the use of monotherapy or polytherapy. Results: Ninety-seven percent of the patients reported having experienced ADRs related to AEDs. The greatest number of seizures affected the group of patients treated with monotherapy (both at baseline and at followup), but the greatest number of ADRs were observed among patients treated with polytherapy. In patients on monotherapy, the most frequent ADRs reported at baseline included fatigue and somnolence, and among patients with polytherapy, it was fatigue and hair loss. Conclusion: Children on polytherapy were significantly more likely to develop ADRs compared to those on monotherapy, but a statistically significant improvement in seizure frequency was also observed in the group of patients on polytherapy. Pharmacovigilance is very important in children with AEDs, so that ADRs can be identified early and managed appropriately.

Serum Levels of Lipids and Selected Aminothiols in Epileptic Children—A Pilot Case-Control Study

Background: Standard treatment of epileptic seizures involves the use of antiepileptic drugs (AEDs). Both AEDs themselves and treatment duration may influence the levels of biochemical parameters, e.g., lipids or homocysteine (HCys), that may increase the risk of cardiovascular diseases. The aim of the present study was to compare the levels of lipid parameters, as well as the concentrations of selected aminothiols (i.e., HCys, cysteine, and glutathione) between epileptic children treated with multiple AEDs and children without epilepsy. Methods: In the study, 21 children with epilepsy treated with two or more AEDs for at least 6 months (8 girls and 13 boys, mean age 7.03 ± 4.51) and 23 children without epilepsy (7 girls and 16 boys, mean age 7.54 ± 3.90) were prospectively analyzed. Lipid parameters, i.e., total cholesterol (TC), triglycerides (TG), low density lipoprotein (LDL) and high density lipoprotein (HDL), and levels of selected aminothiols were determined in the blood serum. Results: No differences in the mean levels of lipid parameters and in the mean values of lipid ratios (TC/HDL, TG/HDL, LDL/HDL) were observed between the total groups as well as in the sex subgroups. HCys and cysteine levels did not differ between the patients and controls. We observed significantly lower levels of glutathione in children with epilepsy than in children without epilepsy (1.49 ± 0.35 µmol/L vs. 2.39 ± 1.17 µmol/L, respectively) (p < 0.001). Glutathione level was also lower in boys with epilepsy than in boys without epilepsy (p = 0.007). Similarly, epileptic girls had statistically decreased levels of glutathione when compared to girls without epilepsy (p = 0.006). Conclusions: A lower level of glutathione is observed in pediatric patients with epilepsy treated with two or more AEDs for at least 6 months. This indicates the oxidative stress of the patients treated with AEDs, which in turn may affect their well-being, and in the case of chronic occurrence resulting from long-term treatment, also on the function of the liver and the condition of the cardiovascular system.

Impact of medicines regulatory risk communications in the UK on prescribing and clinical outcomes: Systematic review, time series analysis and meta-analysis

AIMS

Regulatory risk communications are important to ensure medication safety, but their impact is poorly understood. The aim was to quantify the impact of UK risk communications on medication use and other outcomes.

METHODS

We conducted a systematic review of studies reporting prescribing/health outcome data relevant to UK regulatory risk communication. Data were reanalysed using interrupted time series regression 12 months after each regulatory intervention. Mean changes were pooled using random-effects generic inverse variance examining the following subgroups: drug withdrawals; restrictions/changes in indications; be aware messages without specific recommendations for action; communication via direct healthcare practitioner communications; communication via drug bulletins.

RESULTS

Of 11 466 articles screened, 40 studies examining 25 UK regulatory risk communications were included. Product withdrawals, restriction in indications and be aware communications were associated with relative mean changes of -78% (95% confidence interval [CI] -60 to -96%), -34% (95% confidence interval [CI] -12 to -55%) and -11% (95%CI -8 to -15%) in targeted drug prescribing respectively. Direct healthcare professional communications were associated with relative mean changes of -47% (95%CI -27 to -68%) compared to -13% (95%CI -6 to -20%) for drug bulletins. Of 7 studies examining unique health outcomes related to the safety concern, risk communications were associated with a mean -10% (95%CI -3 to -16%) decrease in intended and a 7% (95%CI 4 to 10%) increase in unintended health outcomes.

DISCUSSION

UK regulatory risk communications were associated with significant changes in targeted prescribing and potential changes in clinical outcomes. Further research is needed to systematically study the impact of regulatory interventions.

Patterns of antiepileptic drugs use in epileptic pediatric patients in Jordan

OBJECTIVE

To determine prescribing patterns of antiepileptic drugs (AEDs) in pediatric patients with confirmed diagnosis of epilepsy, and to provide knowledge of general practice of physicians.

METHODS

The study was a multi-center crosssectional observational study, in specialized clinics for management of epilepsy in north, central and south Jordan. This study was conducted from January 2014 to July 2014. These were 3 from university tertiary care hospitals and 4 from governmental tertiary care hospitals.

RESULTS

A total of 694 pediatric patients were included. Monotherapy AED use had the highest frequency 465 (67.0%), followed by dual therapy 162 (23.3%). The frequency of monotherapy in university hospitals was lower than governmental hospitals (p<0.05); however, Polytherapy was more frequent in younger children. Two old AEDs were most frequently prescribed as a monotherapy; Valproic acid 235 (50.5%) and carbamazepine 155 (33.3%). The most common combination in dual therapy was valproic acid with carbamazepine 28 (17.3%). The second most common combinations were carbamazepine with levetiracetam 21 (13.0%) or valproic acid with levetiracetam 20 (12.3%).

CONCLUSION

Older AED remain first line drugs for use in both monotherapy and combination therapy for epileptic disorders. Polytherapy is associated with younger kids and being treated in a university hospital.

Protocol for a prospective observational study of adverse drug reactions of anti-epileptic drugs in children in the UK

BACKGROUND

Epilepsy is a common chronic disease of children that can be treated with anti-epileptic drugs (AEDs). AEDs, however, have significant side effects. Newer AEDs are thought to have fewer side effects. There have, however, been few comparative studies of AED toxicity. The aim is to compare the safety profile of the most frequently used AEDs by performing a multicentre prospective cohort study. This protocol describes the planned study.

DESIGN

A multicentre prospective cohort study of children on AED treatment in hospitals across the UK. Ethical approval will be obtained.

SAMPLE SIZE

Three thousand children on treatment for epilepsy will be recruited from paediatric clinics. It is expected that this sample size will have the potential to compare toxicity between the most frequently used AEDs.

DURATION OF STUDY

24 months.

OUTCOME MEASURE

Adverse drug reactions (ADRs) to AEDs. These will be identified by the use of a validated questionnaire, the Paediatric Epilepsy Side Effect Questionnaire. They will be evaluated using the Naranjo algorithm. Preventability will be assessed using the Schumock and Thornton scale.

DISCUSSION

Toxicity of individual AEDs when given as monotherapy and polytherapy will be determined. Additionally, discontinuation rates due to ADRs will be determined. The data will assist clinicians in choosing AEDs with the least toxicity.

Medication safety research by observational study design

Observational studies have been recognised to be essential for investigating the safety profile of medications. Numerous observational studies have been conducted on the platform of large population databases, which provide adequate sample size and follow-up length to detect infrequent and/or delayed clinical outcomes. Cohort and case-control are well-accepted traditional methodologies for hypothesis testing, while within-individual study designs are developing and evolving, addressing previous known methodological limitations to reduce confounding and bias. Respective examples of observational studies of different study designs using medical databases are shown. Methodology characteristics, study assumptions, strengths and weaknesses of each method are discussed in this review.

Trends in Antiepileptic Drug Prescriptions for Childhood Epilepsy at a Tertiary Children's Hospital in Korea, 2001-2012

OBJECTIVES

Longitudinal prescription patterns of antiepileptic drugs (AEDs) have not been described to date in Korea. Here we aimed to describe AED prescribing trends over a 12-year period and assess age differences in AED prescribing patterns in a pediatric epilepsy population.

METHODS

We retrieved and analyzed all AED prescribing and dispensing data in 2001-2012 in patients aged 0-18 years with an established diagnosis of epilepsy at the largest tertiary children's hospital in Korea. AEDs included for analysis were classified as older (i.e., carbamazepine, ethosuximide, phenobarbital, phenytoin, and valproic acid) and newer (i.e., gabapentin, lamotrigine, levetiracetam, oxcarbazepine, pregabalin, topiramate, vigabatrin, zonisamide, lacosamide, and rufinamide) on the basis of market availability before versus after 1991.

RESULTS

A total of 5593 patients with epilepsy were prescribed an AED during the 12-year period. The proportion of newer AED prescriptions was 52.6 % in 2001 and continuously increased to 74.3 % in 2012. Oxcarbazepine was most widely used, followed by valproic acid. While carbamazepine and vigabatrin use progressively decreased over the 12-year period, those of lamotrigine and topiramate rapidly increased. Age differences in prescribing patterns were observed. Polytherapy was observed in 49.7 % of the total population, while 83.9 % of new users were prescribed monotherapy.

CONCLUSION

This study provided updated information on AED prescription trends for childhood epilepsy. We found a progressive increase in the use of newer AEDs. However, valproic acid, the only prevalent older AED, continued to be widely prescribed. A high rate of polytherapy among the prescriptions overall raises some safety concerns.

Drug Utilisation Patterns in Children Admitted to a Paediatric General Medical Ward in Five Countries

Objective

To investigate and compare drug prescription patterns in children admitted to a paediatric general medical ward in five countries.

Methods

A prospective cohort study conducted on paediatric medical wards in the UK, Germany, Australia, Hong Kong (HK) and Malaysia. Data were collected over 3 months in each country except in Australia (1 month). All medications prescribed were classified according to the WHO Anatomical Therapeutic Chemical (ATC) classification. For each drug, frequency of prescriptions and patient exposures were calculated for ATC anatomical and therapeutic levels overall and by country.

Results

One thousand two hundred and seventy-eight patients were included (Australia 146, Germany 376, UK 313, HK 143 and Malaysia 300); 89.2 % of patients (1140) received medications, median 3 (interquartile range 2–5) drugs per patient. 5367 drugs were prescribed. The most frequently prescribed therapeutic groups in all countries were: systemic antibacterials (1355; 25.2 %), analgesics/non-steroidal anti-inflammatory drugs (NSAIDs) (1173; 21.8 %) and drugs for obstructive airway diseases (472; 8.8 %). Overall, 65.1 % (742) of patients received at least one systemic antibacterial, 63.7 % (726) received one or more analgesic/NSAIDs, and 23.6 % (269) received ‘drugs for obstructive airway diseases’. The number of patients exposed to these groups differed significantly between countries (p < 0.05). Paracetamol was the most frequently prescribed in all countries, but metamizole was only used in Germany. Morphine was mainly prescribed in the UK.

Conclusion

This study provides an overview of drug use patterns in five culturally and ethnically diverse countries. The most frequently used therapeutic groups were similar, but the proportion of patients treated differed between countries. Also within a therapeutic group the specific drug used varied between countries.

Safety of lamotrigine in paediatrics: a systematic review

OBJECTIVES

To identify adverse drug reactions associated with lamotrigine in children and compare the safety profile with other antiepileptic drugs.

SETTING

Databases EMBASE (1974-April 2015), MEDLINE (1946-April 2015), PubMed and the Cochrane library for randomised controlled trials were searched for studies on safety of lamotrigine.

PARTICIPANTS

All studies involving paediatric patients aged ≤ 18 years who have received at least a single dose of lamotrigine with safety as an outcome measure were included.

PRIMARY AND SECONDARY OUTCOME MEASURES

The primary outcome measure was safety of lamotrigine. Drug interaction of lamotrigine was the secondary outcome.

RESULTS

A total of 78 articles involving 3783 paediatric patients were identified. There were 2222 adverse events (AEs) reported. Rash was the most commonly reported AE, occurring in 7.3% of the patients. Stevens-Johnson syndrome was rarely reported, with a risk of 0.09 per 100 patients. Discontinuation due to an adverse drug reaction (ADR) was recorded in 72 children (1.9% of all treated patients). Fifty-eight per cent of treatment discontinuation was attributed to different forms of rash and 21% due to increased seizures. Children on lamotrigine monotherapy had lower incidences of AEs. Headache (p=0.02), somnolence (<0.001), nausea (p=0.01), vomiting (p<0.001), dizziness (p<0.001) and abdominal pain (p=0.01) were significantly lower among children on monotherapy.

CONCLUSIONS

Rash was the most common ADR of lamotrigine and the most common reason for treatment discontinuation. Children receiving polytherapy have a higher risk of AEs than monotherapy users.

TRIAL REGISTRATION NUMBER

CRD42013006910.

Active surveillance of visual impairment due to adverse drug reactions: findings from a national study in the United Kingdom

As visual impairment (VI) due to adverse drug reactions (ADR) is rare in adults and children, there is an incomplete evidence base to inform guidance for screening and for counseling patients on the potential risks of medications. We report on suspected drugs and the eye conditions found in a national study of incidence of diagnosis of visual impairment due to suspected ADR. Case ascertainment was via the British Ophthalmological Surveillance Unit (BOSU), between March 2010 and February 2012, with follow-up after 6 months. Case definition: any child or adult with bilateral or unilateral visual impairment due to a suspected ADR, using distance acuity worse than Snellen 6/18 (logMAR 0.48) in the better eye (bilateral) or affected eye (unilateral). Anonymized patient information on potential cases was provided by managing ophthalmologists, comprising visual status before and after suspected ADR, ophthalmic condition attributable to the ADR, preexisting eye disease and prescribed medications at the time of the ADR. Permanency and causality of the visual impairment were confirmed by the managing clinician, after 6 months, using the WHO Uppsala Monitoring Committee criteria. Over 2 years, 36 eligible cases were reported of whom 23 had permanent VI. While most cases were due to drugs known to have adverse side-effects, some were unanticipated sporadic cases. Visual impairment due to ADRs is rare. However, with for example, increasing polypharmacy in the elderly, monitoring of ocular ADRs, although challenging, is necessary.

Comparison of prescription drug costs in the United States and the United kingdom, part 4: antibiotics in young children

OBJECTIVES

To compare the usage and cost of antibiotics in the United States and United Kingdom in children younger than 10 years.

METHODS

A follow up of some 160,000 young children enrolled in U.S. private health insurance companies and an equal number in general practices in the United Kingdom in 2009, based on two prospectively designed and documented electronic medical databases.

MAIN RESULTS

Percentage of young children in each country prescribed an antibiotic together with the estimated total annual cost.

PRINCIPAL CONCLUSIONS

In the United States, ~75% of privately insured children were prescribed one or more antibiotics compared with an estimated 50% in the United Kingdom. The annual cost was more than five times higher in the United States compared with the United Kingdom The usage and cost of antibiotics in young privately insured children is far higher in the United States than in the United Kingdom, where the government pays the cost of prescription drugs.

Systematic review and meta-analysis of the efficacy and safety of perampanel in the treatment of partial-onset epilepsy

INTRODUCTION

Perampanel is a first-in-class antiepileptic drug approved for adjunctive treatment of partial-onset seizure in patients aged 12 years or older. Published randomised controlled trials (RCTs) had small sample sizes, and meta-analyses have included too few studies to draw conclusive results for the assessment of tolerability, efficacy and safety of perampanel. There is a need to conduct a meta-analysis with a larger dataset and an appropriate study design.

OBJECTIVE

The aim of this study was to systematically review the efficacy and safety of perampanel in the treatment of partial-onset epilepsy.

METHODS

Electronic and clinical trials databases were searched for RCTs of perampanel published up to March 2013. Outcomes of interest were 50 % responder rates, seizure freedom, treatment-emergent adverse events (TEAEs) and incidence of withdrawal. Meta-analysis was performed to investigate the outcomes of interest.

RESULTS

Five RCTs with a total of 1,678 subjects were included. The 50 % responder rates were significantly greater in patients receiving 4, 8 and 12 mg perampanel versus placebo, with risk ratios of 1.54 (95 % CI 1.11-2.13), 1.80 (95 % CI 1.38-2.35) and 1.72 (95 % CI 1.17-2.52), respectively. There was no statistical evidence of a difference in seizure freedom between 8 or 12 mg perampanel and placebo. Of the five commonly reported TEAEs included, both dizziness and somnolence were statistically associated with 8 mg perampanel, whilst dizziness was statistically associated with 12 mg perampanel. Incidences of withdrawal due to adverse events were significantly higher in the 8 mg and 12 mg perampanel groups versus placebo.

CONCLUSION

The use of perampanel resulted in a statistically significant reduction of seizure frequency with respect to the 50 % responder rate in patients with partial-onset epilepsy. Perampanel is well tolerated at 4 mg and reasonably tolerated at 8 and 12 mg. Further clinical and pharmacovigilance studies are required to investigate the long-term efficacy and safety of perampanel in the management of other types of epilepsy.

Comparison of prescription drug costs in the United States and the United Kingdom, Part 1: statins

STUDY OBJECTIVE

To compare the annual cost of statins in the United States and in the United Kingdom.

DESIGN

Matched-cohort cost analysis.

DATA SOURCES

U.K. General Practice Research Database (GPRD), and MarketScan Commercial Claims and Encounters Database, a large, U.S. self-insured medical claims database.

STUDY POPULATION

We initially identified 1.6 million people in the GPRD who were younger than 65 years of age in 2005. These people were then matched by year of birth and sex with 1.6 million people in the U.S. database. From this matched pool, we estimated that 280,000 people aged 55-64 years from each country in 2005 were prescribed at least one drug. Of these, 91,474 (33%) in the U.S. were prescribed a statin compared with 68,217 (24%) in the U.K. After excluding those who did not receive statins continuously or who switched statins during the year, there remained 61,470 in the U.S. and 45,788 in the U.K. who were prescribed a single statin preparation continuously during 2005 (annual statin users). We estimated and compared drug costs (presented in 2005 U.S. dollars) separately in the two countries.

MEASUREMENTS AND MAIN RESULTS

Estimated drug costs were determined by random sampling. Estimated annual costs/patient in the U.S. ranged from $313 for generic lovastatin to $1428 for nongeneric simvastatin. In the U.K., annual costs/patient ranged from $164 for generic simvastatin to $509 for nongeneric atorvastatin. The total annual cost of the continuous receipt of statins in the U.S. was $64.9 million compared with $15.7 million in the U.K. In June 2006, after our study results were analyzed, the U.S. Food and Drug Administration approved generic simvastatin. We thus derived cost estimates for simvastatin use during 2006 and found that more than 60% of simvastatin users switched to the generic product, which reduced the cost/pill by more than 50%.

CONCLUSION

The cost paid for statins in the U.S. for people younger than 65 years, who were insured by private companies, was approximately 400% higher than comparable costs paid by the government in the U.K. Available generic statins were substantially less expensive than those that were still under patent in both countries.

A retrospective study on the usage of antiepileptic drugs in Asian children from 2000 to 2009 in the largest pediatric hospital in Singapore

PURPOSE

In light of the increasing usage of the newer antiepileptic drugs (AEDs) in other countries, we reviewed the prescribing pattern of AEDs in Singapore over the last 10 years (2000-2009).

METHODS

A retrospective review of pharmacy dispensing records solicited from the only children's hospital in Singapore was performed to analyze the trend in AEDs prescribing in the last 10 years. We also examined the correlation between the serum concentrations of valproic acid (VPA), the most-prescribed AED, and seizure control. Descriptive and inferential statistical analyses were then performed on the findings.

RESULTS

A total of 41 671 prescriptions on AEDs were retrieved and analyzed. Despite the introduction of the second-generation AEDs, the first generation AEDs still dominate epilepsy treatment in Asian children, with VPA being the mostly prescribed AED (about 40% of the total AEDs usage). The majority of patients (62.8%) were on monotherapy. The mean VPA serum concentration in patients with good seizure control was 68.6 µg/ml (SD = 26.4 µg/ml; range = 12.2-138.0 µg/ml), which was statistically higher than the mean VPA concentration of 57.7 µg/ml (SD = 27.1 µg/ml; range = 11.1-149.0 µg/ml) in patients with poor seizure control (p < 0.0001).

CONCLUSION

With VPA being the most prescribed AED in our clinical practice, and the finding in this study that with careful classification of the patients' condition, serum concentrations of VPA generally correlate well with the seizure control, the correct dose titration of VPA with therapeutic drug monitoring is still of paramount importance.

Changes in anticonvulsant prescribing for Australian children: implications for Quality Use of Medicines

AIMS

The evidence-base guiding choices between newer versus established anticonvulsants in children is limited. Inappropriate use exposes children to potentially ineffective and/or harmful medicines. Our objective is to describe recent anticonvulsant prescribing patterns in the Australian paediatric population, evaluating overall trends and extent of off-label prescribing of newer agents.

METHODS

Aggregated national data on 15 anticonvulsants with Pharmaceutical Benefits Scheme subsidy dispensed by community pharmacies for children aged <16 years were obtained from the Drug Utilisation Subcommittee, which is part of the Australian Government Department of Health and Ageing. We analysed trends for the five most prescribed anticonvulsants dispensed between 2002 and 2009 and off-label prescribing for agents where approved Australian product information stipulates a minimum age.

RESULTS

Valproate was the most frequently prescribed anticonvulsant with no marked change in prescription numbers per 1000 children aged 0-16 years (11.3-11.8 prescriptions/year). Lamotrigine was the most frequently prescribed newer anticonvulsant (7.9-9.3 prescriptions/year). Carbamazepine prescriptions decreased by 38% and topiramate prescriptions increased by 19% over the 7-year study period; 3.6% of topiramate prescriptions were off-label (by age) for children aged <2 years. Since Pharmaceutical Benefits Scheme listing in 2003, levetiracetam prescriptions increased steeply to 2.5 prescriptions/year per 1000 children in 2009; 4.2% were off-label for children aged <4 years.

CONCLUSIONS

The substantial reduction in carbamazepine use and corresponding increase in newer anticonvulsant prescribing, including off-label uses, raises questions about potentially suboptimal Quality Use of Medicines. Such major changes in prescribing may have important clinical and economic consequences. Further study to better understand paediatric prescribing choices and outcomes is needed.

Utilization of antiepileptic drugs in Hong Kong children

This study investigated the prescribing patterns of antiepileptic drugs, especially the uptake of newer drugs, among children and adolescents in Hong Kong. Data were retrieved from the Clinical Data Analysis and Reporting System. Children aged 0-19 years who received at least one prescription of anticonvulsants were selected. The study period extended from April 1, 2005 to March 31, 2009. The overall prevalence of anticonvulsants prescribing was 2.23/1000 children in 2005. A slight but steady decline in anticonvulsants prevalence was observed throughout the study period. Valproic acid was the most frequently prescribed drug, followed by carbamazepine and benzodiazepine derivatives. The use of newer anticonvulsants rose significantly, by 26.9%. The use of valproic acid remained unchanged, whereas the use of carbamazepine declined by 20%. Among newer drugs, the use of levetiracetam increased fourfold, and that of oxcarbazepine increased 15-fold. In the youngest age group, phenobarbital was the second most frequently used drug. A significant increase in lamotrigine prescriptions was not observed among adolescents. The persistent increase in using newer antiepileptic drugs implies not only an increase in drug expenditure. It also reflects the need to assess cost-effectiveness in terms of long-term outcomes, quality of life, and health economic outcomes.

Comparison of prescription drug costs in the United States and the United Kingdom, part 2: proton pump inhibitors

STUDY OBJECTIVE

To compare the annual cost of proton pump inhibitors (PPIs) in the United States and in the United Kingdom.

DESIGN

Matched-cohort cost analysis.

DATA SOURCES

U.K. General Practice Research Database (GPRD) and MarketScan Commercial Claims and Encounter Database, a large, U.S. self-insured medical claims database.

STUDY POPULATION

We initially identified more than 1 million people in the GPRD who were younger than 65 years of age and who were prescribed at least one prescription drug in 2005. Each of these people was then matched by year of birth and sex to one person in the U.S. database. From the matched pool, we estimated that 280,000 people were aged 55-64 years from each country. Of these, an estimated 27,230 (9.7%) in the U.S. were prescribed a PPI compared with 22,560 (8.1%) in the U.K. After excluding patients who did not receive the PPI continuously or who switched PPIs during the year, there remained 11,292 people in the U.S. and 9923 in the U.K. who were prescribed a single PPI preparation continuously during 2005 (annual PPI users).

MEASUREMENTS AND MAIN RESULTS

Annual drug costs were determined by random sampling. The estimated annual cost/patient in the U.S. ranged from $901 for generic omeprazole to $1485 for lansoprazole. In the U.K., the annual costs were similar, approximately $400 for each PPI, irrespective of whether the agents were available in generic formulation. The total estimated annual cost of PPIs for 2005 in this study group was $14 million in the U.S. compared with $4.1 million in the U.K.

CONCLUSION

The cost of continuous use of PPIs covered by private insurance companies in the U.S. in 2005 was more than 3 times the cost covered by the U.K. government. This result is consistent with the findings of an earlier study on relative costs of statins between the countries.

Comprehensive comparison of drug prescribing in the United States and United Kingdom

STUDY OBJECTIVE

To compare the frequency of outpatient drug prescribing in the United States and United Kingdom according to individual drugs and therapeutic categories during 2004-2006.

DESIGN

Retrospective prescription record review.

DATA SOURCES

United Kingdom General Practice Research Database, and the MarketScan Commercial Claims and Encounters Database for U.S. data.

SUBJECTS

In the U.K. database, we identified 1.6 million people younger than 65 years who were prescribed at least one prescription drug in at least one of the calendar years during the study period (2004-2006). For comparison, for each U.K. person identified, we randomly identified one person of the same sex and year of birth in the U.S. database who was also prescribed at least one drug in the same calendar year.

MEASUREMENTS AND MAIN RESULTS

We compared the frequency of prescribing of individual drugs, as well as selected therapeutic categories. Substantially higher proportions of people in the United States were prescribed antibiotics, statins, and postmenopausal hormones, but asthma drugs were prescribed more frequently in the United Kingdom. In those younger than 20 years, antidepressants and antipsychotics were prescribed more than twice as frequently in the United States, and males in the United States were far more likely to be prescribed drugs for attention-deficit-hyperactivity disorder than were their counterparts in the United Kingdom.

CONCLUSION

This study provides documented quantification of differing patterns of drug use in the United States and United Kingdom during 2004-2006. The higher proportionate prescribing for most indications in the United States and the greater use of drugs under patent suggest that monetary costs are likely to be considerably higher in the United States than in the United Kingdom.

Mortality rates and causes of death in children with epilepsy prescribed antiepileptic drugs: a retrospective cohort study using the UK General Practice Research Database

BACKGROUND

Patients with epilepsy, including children, have an increased risk of mortality compared with the general population. Antiepileptic drugs (AEDs) were the most frequent class of drugs reported in a study looking at fatal suspected adverse drug reactions in children in the UK.

OBJECTIVE

The objective of the study was to identify cases and causes of death in a paediatric patient cohort prescribed AEDs with an associated epilepsy diagnosis.

METHODS

This was a retrospective cohort study supplemented with general practitioner-completed questionnaires, post-mortem reports and death certificates. The setting was UK primary care practices contributing to the General Practice Research Database. Participants were children and adolescents aged 0-18 years prescribed AEDs between 1993 and 2005. Causality assessment was undertaken by a consensus panel comprising paediatric specialists in neuropathology, neurology, neuropsychiatry, paediatric epilepsy, pharmacoepidemiology and pharmacy to determine crude mortality rate (CMR) and standardized mortality ratios (SMRs), and the likelihood of an association between AED(s) and the event of death.

RESULTS

There were 6190 subjects in the cohort (contributing 26,890 person-years of data), of whom 151 died. Median age at death was 8.0 years. CMR was 56.2 per 10,000 person-years and the SMR was 22.4 (95% CI 18.9, 26.2). The majority of deceased subjects had severe underlying disorders. Death was attributable to epilepsy in 18 subjects; in 9 the cause of death was sudden unexpected death in epilepsy (SUDEP) [3.3 per 10 000 person-years (95% CI 1.5, 6.4)]. AEDs were probably (n = 2) or possibly (n = 3) associated causally with death in five subjects. Two status epilepticus deaths were associated causally with AED withdrawal.

CONCLUSIONS

Children prescribed AEDs have an increased risk of mortality relative to the general population. Most of the deaths were in children with serious underlying disorders. A small number of SUDEP cases were identified. AEDs are not a major cause of death but in a small proportion of cases, a causal relationship between death and AEDs could not be excluded.

New drugs for pediatric epilepsy

The last 2 decades have witnessed an unprecedented period of new antiepileptic drug (AED) development. Newer-generation AEDs have been developed with the intention of improving the ease of use, decreasing drug interactions, decreasing adverse side effects, and identifying drugs with unique mechanisms of action, some of which may bear relevance to potential neuroprotective activity. Drug trials have also been refined in some cases to evaluate AED efficacy in children and against distinct epilepsy syndromes. This progress provides many new treatment options for the child neurologist facing children with epilepsy but also introduces the burden of determining appropriate AED choices. Here we highlight 6 new antiepileptic medications recently approved or pending approval for use in the United States: lacosamide, rufinamide, vigabatrin, retigabine, brivaracetam, and clobazam. For each of these medications, we present information regarding the history of drug development, proposed mechanism(s) of action, pharmacokinetics and recommended dosing, evidence for clinical efficacy, tolerability, and when, available, any unique features that are relevant for the pediatric population.

Comparison of antiepileptic drug prescribing in children in three European countries

PURPOSE

Antiepileptic drug (AED) use in young people is increasing. However, evidence of its use at a multinational level is limited. This study aims to characterize AED prescribing in the young in three European countries and to assess the capacity of drug safety surveillance.

METHODS

A retrospective cohort study was conducted in 2001-2005 using primary care databases: PEDIANET (Italy, 0-11 years), IPCI (The Netherlands, 0-18 years), and IMS Disease Analyzer (United Kingdom, 0-18 years). Prescribing prevalence was calculated by country, patient age, and drug type.

RESULTS

In 2005, AED prevalence in children (0-11 years) was highest in Italy [3.9 subjects/1,000 person-years (PY)] followed by the United Kingdom (3.0 subjects/1,000 PY) and The Netherlands (2.2 subjects/1,000 PY). Over the study period, prescribing prevalence in 0-11 year olds was stable in all countries. In contrast, a steady rise of AED prevalence was observed in adolescents (12-18 years) in the United Kingdom (p = 0.0003) but not in The Netherlands (p = 0.88). All countries showed a slight increase in prevalence for newer AEDs. Simultaneously, the prevalence of conventional AEDs decreased in The Netherlands and Italy, but not in the United Kingdom. In 2005, lamotrigine use was highest in The Netherlands and the United Kingdom, whereas topiramate was favored in Italy.

DISCUSSION

In Europe, conventional AEDs are still the main treatment choice for children with epilepsy, and the use of newer AEDs remains low. Our study highlights a lack of research capacity to conduct multinational AED safety studies in children. Further work should explore large databases and other health care settings to meet these research needs.

Antiepileptic drugs in children in developing countries: research and treatment guideline needs

Epilepsy is the most common neurologic disorder in childhood. Effective interventions are available for treatment; however, the treatment gap in children is more than 80% in many developing countries. An important reason for this huge treatment gap is limited access to antiepileptic drugs (AEDs). This article discusses the reasons for such a treatment gap, and possible ways forward in improving care of children with epilepsy worldwide.

Prioritising neonatal medicines research: UK Medicines for Children Research Network scoping survey

Background

The dosing regimen and indications for many medicines in current use in neonatology are not well defined. There is a need to prioritise research in this area, but currently there is little information about which drugs are used in UK neonatal units and the research needs in this area as perceived by UK neonatologists.

Methods

The Neonatal Clinical Studies Group (CSG) of the Medicines for Children Research Network (MCRN) undertook a 2 week prospective scoping survey study to establish which medicines are used in UK neonatal units; how many babies are receiving them; and what clinicians (and other health professionals) believe are important issues for future research.

Results

49 out of 116 units responded to at least one element of the survey (42%). 37 units reported the number of neonates who received medicines over a 2 week period. A total of 3924 medicine-patient pairs were reported with 119 different medicines. 70% of medicine-patient pairs involved medicines that were missing either a license or dose for either term or preterm neonates. 4.3% of medicine-patient pairs involved medicines that were missing both license and dose for any neonate. The most common therapeutic gap in need of additional research identified by UK neonatologists was chronic lung disease (21 responding units), followed by patent ductus arteriosus and vitamin supplements (11 responding units for both)

Conclusion

The research agenda for neonatal medicines can be informed by knowledge of current medicine use and the collective views of the neonatal community.

Attention-deficit hyperactivity disorder: treatment discontinuation in adolescents and young adults

BACKGROUND

Symptoms of attention-deficit hyperactivity disorder (ADHD) are known to persist into adulthood in the majority of cases.

AIMS

To determine the prevalence of methylphenidate, dexamfetamine and atomoxetine prescribing and treatment discontinuation in adolescents and young adults.

METHOD

A descriptive cohort study using the UK General Practice Research Database included patients aged 15-21 years from 1999 to 2006 with a prescription for a study drug.

RESULTS

Prevalence of prescribing averaged across all ages increased 6.23-fold over the study period. Overall, prevalence decreased with age: in 2006, prevalence in males dropped 95% from 12.77 per 1000 in 15-year-olds to 0.64 per 1000 in 21-year-olds. A longitudinal analysis of a cohort of 44 patients aged 15 years in 1999 demonstrated that no patient received treatment after the age of 21 years.

CONCLUSIONS

The prevalence of prescribing by general practitioners to patients with ADHD drops significantly from age 15 to age 21 years. The fall in prescribing is greater than the reported age-related decrease in symptoms, raising the possibility that treatment is prematurely discontinued in some young adults in whom symptoms persist.

Databases for pediatric medicine research in Europe--assessment and critical appraisal

PURPOSE

To identify and describe European health care databases that can be used for pediatric pharmacoepidemiological research.

METHODS

A web-based survey was conducted among all European databases that were listed on the website of the International Society of Pharmacoepidemiology (ISPE) and/or known by an expert group. The survey comprised of questions regarding (a) the nature of the database, (b) database size, (c) demographic, clinical and drug related data provided, (d) cost, and (e) accessibility of the database.

RESULTS

A total of 25 data sources from 12 European countries were identified and invited to participate in the survey. Responses were obtained from 21 (84%) databases located in 10 different European countries. Seventeen databases were included in the assessment comprising a total of at least 9 million children aged 0-18 years. The majority of databases are based on outpatient data and all keep either prescription or drug dispensing data. Ten databases are based on electronic patient records from primary care physicians and five databases are predominantly claims oriented. Three databases do not belong to either of the above mentioned categories. Almost all of the databases can be used for pediatric drug utilization studies. For drug safety studies it is more appropriate to use electronic patient record databases because of the available clinical information and the potential to obtain additional information.

CONCLUSIONS

There are many European healthcare databases providing an enormous potential for pediatric pharmacoepidemiological research. Future research should focus on methods to bring data from different databases together to use the full capacity effectively.

An increase in the prevalence of type 1 and 2 diabetes in children and adolescents: results from prescription data from a UK general practice database

WHAT IS ALREADY KNOWN ABOUT THIS SUBJECT

Increasing antidiabetic drugs use in youths has been reported in the USA, however there is a lack of epidemiological evidence in the UK. There is an increase in the prevalence of both type 1 and 2 diabetes, but precise estimates are difficult to obtain and as such are uninformative for future health services planning.

WHAT THIS STUDY ADDS

The prevalence of children receiving insulin and oral antidiabetic drugs has increased twofold and eightfold, respectively, between 1998 and 2005. The data reflect the prevalence of both type 1 and type 2 diabetes rapidly increase in recent years. The prevalence of antidiabetic drug use increases with increasing age, especially among those aged 12-18 years. Consideration needs to be given to the funding and design of future services for children and particularly adolescents with diabetes to take account of these epidemiological findings.

AIMS

Despite evidence of an increase in the incidence of both type 1 and type 2 diabetes in youths, there are few data on the prevalence of either type in children and adolescents. The aim of this study was to investigate the prevalence of childhood diabetes over an 8-year period in the UK.

METHODS

This was a retrospective cohort study that covered 8 years (January 1998 to December 2005) of UK IMS Disease Analyzer (IMS DA) data. The cohort comprised all children and adolescents aged 0-18 years who received at least one antidiabetic drug prescription during the study period. The prevalence of antidiabetic drug prescribing was used as a proxy for diabetes itself.

RESULTS

Data were available on 505 754 children aged 0-18 years and a total of 37 225 antidiabetic prescriptions were issued. Insulin use increased significantly from 1.08 per 1000 children [95% confidence interval (CI) 0.96, 1.20] in 1998 to 1.98 (95% CI 1.80, 2.10) in 2005 (P < 0.001), more markedly in those aged 12 and 18 years. The use of oral antidiabetic drugs for diabetes treatment rose significantly from 0.006 per 1000 children in 1998 (95% CI 0.0043, 0.017) to 0.05 (95% CI 0.025, 0.080) (P < 0.001) in 2005.

CONCLUSIONS

This study indicates a significant increase in prevalence on both type 1 and type 2 diabetes treatment in children and adolescents in the UK. Thus, this supporting evidence from other sources that the prevalence of childhood diabetes is rising rapidly. Further epidemiological studies are required to investigate the aetiology and risk factors.

Antiepileptic drug utilization in children from 1997-2005--a study from the Netherlands

OBJECTIVE

To investigate the utilization of antiepileptic drugs (AEDs) in Dutch children and compare this with guidelines on the treatment of epilepsy in children.

METHOD

From the Dutch Interaction Database (IADB.nl) we selected children aged 0-19 years who received at least one prescription for an AED (ATC-code beginning with N03A) between 1997 and 2005. We calculated cumulative incidences and prevalences per 1000 children per year, stratified by age-category, sex and type of AED, and the total number of months each patient received at least one prescription of AEDs, and we counted the number of person-months and AEDs prescribed. For each AED, proportions of person-months were calculated for mono- and combination therapy. Kaplan-Meier survival analysis was used to analyse the duration of AED use, stratified by sex.

RESULTS

The overall prevalence of the prescription of AEDs to children was constant at approximately 4.0 per 1000 children during the years of the study. The overall cumulative incidence from 1997-2005 was 0.67 per 1000 children. When stratified by age category or sex, there were no relevant differences in incidence or prevalence. Valproic acid was the most frequently prescribed drug, followed by carbamazepine and lamotrigine. In 20.3% of all person-months, patients received combination therapy; of these, 34.2% received combination therapy for 3 person-months or less. The older AEDs were prescribed more often as monotherapy than combination therapy, in contrast with the newer AEDs, for which the opposite was true. The 50% survival probability (= time period when 50% of children had stopped using AEDs) was around 2 years, with a significantly lower discontinuation of treatment for girls than boys (P = 0.04).

CONCLUSION

The overall cumulative incidence of AEDs was determined to be 0.67 per 1000 children, and the prevalence 4.0 per 1000 children. The most frequently prescribed drug is valproic acid, followed by carbamazepine and lamotrigine. The prescribing of AEDs seems to be in conformity with the overall recommendations of the guidelines on the treatment of epilepsy in children.