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The epidemiology of pharmacologically treated attention deficit hyperactivity disorder (ADHD) in children, adolescents and adults in UK primary care.

McCarthy S, Wilton L, Murray ML, Hodgkins P, Asherson P, Wong IC - BMC Pediatr (2012)

Bottom Line: Prevalence (per 1000 persons in the mid-year THIN population) increased within each age category from 2003 to 2008 [6-12 years: from 4.8 (95% CI: 4.5-5.1) to 9.2 (95% CI: 8.8-9.6); 13-17 years: from 3.6 (95% CI: 3.3-3.9) to 7.4 (95% CI: 7.0-7.8); 18-24 years: from 0.3 (95% CI: 0.2-0.3) to 1.1 (95% CI: 1.0-1.3); 25-45 years: from 0.02 (95% CI: 0.01-0.03) to 0.08 (95% CI: 0.06-0.10); >45 years: from 0.01 (95% CI: 0.00-0.01) to 0.02 (95% CI: 0.01-0.03).Whilst male patients aged 6-12 years had the highest prevalence; the relative increase in prescribing was higher amongst female patients of the same age - the increase in prevalence in females aged 6-12 years was 2.1 fold compared to an increase of 1.9 fold for their male counterparts.Incidence (per 1000 persons at risk in the mid-year THIN population) was highest for children aged 6-12 years.

View Article: PubMed Central - HTML - PubMed

Affiliation: School of Pharmacy, University College Cork, Cork, Ireland. s.mccarthy@ucc.ie

ABSTRACT

Background: Attention Deficit Hyperactivity Disorder (ADHD) is a common neurodevelopmental disorder characterised by the symptoms of inattention, impulsivity and hyperactivity. ADHD was once perceived as a condition of childhood only; however increasing evidence has highlighted the existence of ADHD in older adolescents and adults. Estimates for the prevalence of ADHD in adults range from 2.5-4%. Few data exist on the prescribing trends of the stimulants methylphenidate and dexamfetamine, and the non-stimulant atomoxetine in the UK. The aim of this study was to investigate the annual prevalence and incidence of pharmacologically treated ADHD in children, adolescents and adults in UK primary care.

Methods: The Health Improvement Network (THIN) database was used to identify all patients aged over 6 years with a diagnosis of ADHD/hyperkinetic disorder and a prescription for methylphenidate, dexamfetamine or atomoxetine from 2003-2008. Annual prevalence and incidence of pharmacologically treated ADHD were calculated by age category and sex.

Results: The source population comprised 3,529,615 patients (48.9% male). A total of 118,929 prescriptions were recorded for the 4,530 patients in the pharmacologically treated ADHD cohort during the 6-year study. Prevalence (per 1000 persons in the mid-year THIN population) increased within each age category from 2003 to 2008 [6-12 years: from 4.8 (95% CI: 4.5-5.1) to 9.2 (95% CI: 8.8-9.6); 13-17 years: from 3.6 (95% CI: 3.3-3.9) to 7.4 (95% CI: 7.0-7.8); 18-24 years: from 0.3 (95% CI: 0.2-0.3) to 1.1 (95% CI: 1.0-1.3); 25-45 years: from 0.02 (95% CI: 0.01-0.03) to 0.08 (95% CI: 0.06-0.10); >45 years: from 0.01 (95% CI: 0.00-0.01) to 0.02 (95% CI: 0.01-0.03). Whilst male patients aged 6-12 years had the highest prevalence; the relative increase in prescribing was higher amongst female patients of the same age - the increase in prevalence in females aged 6-12 years was 2.1 fold compared to an increase of 1.9 fold for their male counterparts. Prevalence of treated ADHD decreased with increasing age. Incidence (per 1000 persons at risk in the mid-year THIN population) was highest for children aged 6-12 years.

Conclusions: A trend of increasing prescribing prevalence of ADHD drug treatment was observed over the period 2003-2008. Prevalence of prescribing to adult patients increased; however the numbers treated are much lower than published estimates of the prevalence of ADHD. This study has added to the limited knowledge on ADHD prescribing in primary care, particularly in the area of drug treatment in adulthood.

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Incidence of pharmacologically treated attention deficit hyperactivity disorder (methylphenidate, dexamfetamine or atomoxetine) in patients aged 6-years and over in UK general practice (with 95% confidence intervals).
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Figure 2: Incidence of pharmacologically treated attention deficit hyperactivity disorder (methylphenidate, dexamfetamine or atomoxetine) in patients aged 6-years and over in UK general practice (with 95% confidence intervals).

Mentions: The source population for incidence calculations was 3,226,266 (49.3% male). A total of 2,343 patients were incident during the study period. Incidence of prescribing is illustrated in Figure 2. The analysis shows that the incidence estimates were highest for children (6–12 years) and decreased with increasing age, being very low in adults. The incidence estimates were higher in 2008 than in 2003 for all age groups, although the incidence estimates for children and for adolescents (13–17 years) were highest in 2006. The incidence estimates were much higher for young adults (18–24 years) in 2004, the year in which atomoxetine entered the market, than in all other years except for 2008. When the data were stratified by gender, the incidence estimates were shown to be much lower in females than in males (Table 4). Similarly to prevalence estimates, the incidence estimates increased proportionally more for female children and adolescents than for the males of these age categories. However for young adult males (aged 18–24 years) the increase was 7.23 fold compared to 1.62 fold for young adult female patients.


The epidemiology of pharmacologically treated attention deficit hyperactivity disorder (ADHD) in children, adolescents and adults in UK primary care.

McCarthy S, Wilton L, Murray ML, Hodgkins P, Asherson P, Wong IC - BMC Pediatr (2012)

Incidence of pharmacologically treated attention deficit hyperactivity disorder (methylphenidate, dexamfetamine or atomoxetine) in patients aged 6-years and over in UK general practice (with 95% confidence intervals).
© Copyright Policy - open-access
Related In: Results  -  Collection

License
Show All Figures
getmorefigures.php?uid=PMC3472167&req=5

Figure 2: Incidence of pharmacologically treated attention deficit hyperactivity disorder (methylphenidate, dexamfetamine or atomoxetine) in patients aged 6-years and over in UK general practice (with 95% confidence intervals).
Mentions: The source population for incidence calculations was 3,226,266 (49.3% male). A total of 2,343 patients were incident during the study period. Incidence of prescribing is illustrated in Figure 2. The analysis shows that the incidence estimates were highest for children (6–12 years) and decreased with increasing age, being very low in adults. The incidence estimates were higher in 2008 than in 2003 for all age groups, although the incidence estimates for children and for adolescents (13–17 years) were highest in 2006. The incidence estimates were much higher for young adults (18–24 years) in 2004, the year in which atomoxetine entered the market, than in all other years except for 2008. When the data were stratified by gender, the incidence estimates were shown to be much lower in females than in males (Table 4). Similarly to prevalence estimates, the incidence estimates increased proportionally more for female children and adolescents than for the males of these age categories. However for young adult males (aged 18–24 years) the increase was 7.23 fold compared to 1.62 fold for young adult female patients.

Bottom Line: Prevalence (per 1000 persons in the mid-year THIN population) increased within each age category from 2003 to 2008 [6-12 years: from 4.8 (95% CI: 4.5-5.1) to 9.2 (95% CI: 8.8-9.6); 13-17 years: from 3.6 (95% CI: 3.3-3.9) to 7.4 (95% CI: 7.0-7.8); 18-24 years: from 0.3 (95% CI: 0.2-0.3) to 1.1 (95% CI: 1.0-1.3); 25-45 years: from 0.02 (95% CI: 0.01-0.03) to 0.08 (95% CI: 0.06-0.10); >45 years: from 0.01 (95% CI: 0.00-0.01) to 0.02 (95% CI: 0.01-0.03).Whilst male patients aged 6-12 years had the highest prevalence; the relative increase in prescribing was higher amongst female patients of the same age - the increase in prevalence in females aged 6-12 years was 2.1 fold compared to an increase of 1.9 fold for their male counterparts.Incidence (per 1000 persons at risk in the mid-year THIN population) was highest for children aged 6-12 years.

View Article: PubMed Central - HTML - PubMed

Affiliation: School of Pharmacy, University College Cork, Cork, Ireland. s.mccarthy@ucc.ie

ABSTRACT

Background: Attention Deficit Hyperactivity Disorder (ADHD) is a common neurodevelopmental disorder characterised by the symptoms of inattention, impulsivity and hyperactivity. ADHD was once perceived as a condition of childhood only; however increasing evidence has highlighted the existence of ADHD in older adolescents and adults. Estimates for the prevalence of ADHD in adults range from 2.5-4%. Few data exist on the prescribing trends of the stimulants methylphenidate and dexamfetamine, and the non-stimulant atomoxetine in the UK. The aim of this study was to investigate the annual prevalence and incidence of pharmacologically treated ADHD in children, adolescents and adults in UK primary care.

Methods: The Health Improvement Network (THIN) database was used to identify all patients aged over 6 years with a diagnosis of ADHD/hyperkinetic disorder and a prescription for methylphenidate, dexamfetamine or atomoxetine from 2003-2008. Annual prevalence and incidence of pharmacologically treated ADHD were calculated by age category and sex.

Results: The source population comprised 3,529,615 patients (48.9% male). A total of 118,929 prescriptions were recorded for the 4,530 patients in the pharmacologically treated ADHD cohort during the 6-year study. Prevalence (per 1000 persons in the mid-year THIN population) increased within each age category from 2003 to 2008 [6-12 years: from 4.8 (95% CI: 4.5-5.1) to 9.2 (95% CI: 8.8-9.6); 13-17 years: from 3.6 (95% CI: 3.3-3.9) to 7.4 (95% CI: 7.0-7.8); 18-24 years: from 0.3 (95% CI: 0.2-0.3) to 1.1 (95% CI: 1.0-1.3); 25-45 years: from 0.02 (95% CI: 0.01-0.03) to 0.08 (95% CI: 0.06-0.10); >45 years: from 0.01 (95% CI: 0.00-0.01) to 0.02 (95% CI: 0.01-0.03). Whilst male patients aged 6-12 years had the highest prevalence; the relative increase in prescribing was higher amongst female patients of the same age - the increase in prevalence in females aged 6-12 years was 2.1 fold compared to an increase of 1.9 fold for their male counterparts. Prevalence of treated ADHD decreased with increasing age. Incidence (per 1000 persons at risk in the mid-year THIN population) was highest for children aged 6-12 years.

Conclusions: A trend of increasing prescribing prevalence of ADHD drug treatment was observed over the period 2003-2008. Prevalence of prescribing to adult patients increased; however the numbers treated are much lower than published estimates of the prevalence of ADHD. This study has added to the limited knowledge on ADHD prescribing in primary care, particularly in the area of drug treatment in adulthood.

Show MeSH
Related in: MedlinePlus