Children and Adolescents With Attention Deficit-Hyperactivity Disorder: 1. Prevalence and Cost of Care

1. Children and Adolescents With Attention Deficit-Hyperactivity Disorder: 1. Prevalence and Cost of Care Larry Burd, PhD; Marilyn G. Klug, PhD; Matthew J. Coumbe, PhD; Jacob Kerbeshian, MD

2. Abstract The objective of this study was to use population-based data to estimate the prevalence and cost of treatment for attention-deficit hyperactivity disorder (ADHD). The case population was 7745, and the mean prevalence rate was 3.9%, with a peak prevalence at 10 years of age. For children with ADHD, the annual cost of care was $649 compared with that of controls at $495. Cost of care attributable to ADHD was $694 - $495 = $154 (31%). Utilization by children with ADHD with publicly funded payers was increased 25 to 175% over that of children with privately funded coverage. In North Dakota, the annual cost of care for children with ADHD was $5.1 million, 5.6% of all health care costs for children. The annual attributable cost of care was $1.79 million. Thus, 1.9% of total health expenditures for children was attributable to ADHD. In the United States, the cost of care attributable to children with ADHD would be $2.15 billion annually. (J Child Neurol 2003;18:555-561).

4. Inclusion Criteria: Cases Patients were included in the study as cases with ADHD if at any timed during either year they had an Internal Classification of Diseases, 9th edition (ICD-9), code of 314.00 or (attention-deficit disorder not otherwise specified), 314.00 (inattention type), 314.01 (with hyperactivity/impulsiveness), or 314.8 (with other specific manifestations). The code 314.9 (attention-deficit hyperactivity disorder not otherwise specified) was also included to capture cases from the Diagnostic and Statistical Manual of Mental Disorders-IV (DSM-IV). This is the coding strategy used to specify children with a diagnosis of ADHD in the DSM-IV. If the codes (314.xx) were identified in any order in the diagnostic formulation in the database at any time during the year, the subject was classified as a case.

5. Inclusion Criteria:Controls The controls were all remaining subjects 0 to 21 years of age in the database who did not have an ICD-9 code of 314.00, 314.01, or 314.8 or the DSM-IV code 314.9 in their diagnostic formulation. In this sample, we had 24.5 controls for each case.

6. Limitations The data are from North Dakota, a small rural state with a total population in 1997 of 650,000. The data for this study are health care claims data and might reflect coding error or bias. Two significant populations not represented in these data were uninsured children and the Native American population.

7. Calculation of Costs Two types of costs were defined: base cost and attributable cost. The base cost was the cost a control child generated on average during the year. Attributable costs were costs added to the base cost for a specific illness. The cost and group (ADHD or control) interactions were examined by a linear equation with two cost elements. This database does not include the cost of medication.

10. Comparison of Mean (1996-1997) Costs Between Children With ADHD and Without (Controls) by Payment Method

11. Comparison of Mean (1996-1997) Costs Between Children With ADHD and Without (Controls) by Gender

12. Comparison of Mean (1996-1997) Costs Between Children With ADHD and Without (Controls) by Payment Method

13. Comparison of Mean (1996-1997) Costs Between Children With ADHD and Without (Controls) by Gender

14. Results The prevalence of ADHD increases slowly from birth until 2 years of age, when the prevalence is 0.3%. From 3 through 10 years of age, the prevalence has a mean increase of 1.1% per year. Prevalence peaks at 10.3% at 10 years of age and then decreases at a mean rate of about 1.0% per year until 18 years of age. After 18 years of age, ADHD is diagnosed in 2% of the population.

15. Mean Cost Comparisons The mean annual cost of care for children with ADHD in the Health Care Financing Administration data was $649 per case or 31% more than controls. The annual cost of attributable to ADHD was $154 ($649-$495) per case.

16. Proportion of Mean (1996-1997) Annual Number of Visits Between Children With ADHD and Without (Controls) by Payment Type

17. Proportion of Mean (1996-1997) Annual Number of Visits Between Children With ADHD and Without (Controls) by Gender

18. Proportion of Mean (1996-1997) Annual Number of Visits Between Children With ADHD and Without (Controls) by Payment Type

19. Proportion of Mean (1996-1997) Annual Number of Visits Between Children With ADHD and Without (Controls) by Gender

20. Proportion of Mean (1996-1997) Annual Number of Visits Between Children With ADHD and Without (Controls) by Payment Type

21. Proportion of Mean (1996-1997) Annual Number of Visits Between Children With ADHD and Without (Controls) by Gender

22. Inpatient Data For inpatient data, the mean annual cost of care for children with ADHD was $8861 or 60% more than controls, with an attributable cost of $3332 ($8861-$5529).

23. Outpatient Data For outpatient data, the mean annual cost of care for children with ADHD was $1597. This produced an attributable mean annual cost of care for ADHD of $953 ($1592-$644), which was 148% greater than the cost for controls.

24. Public Payer Type Annual mean costs for children with ADHD with public payers in the Health Care Financing Administration data set were 78% higher than controls and 59% and 176% higher than controls in the inpatients and outpatient data sets, respectively.

25. Private Payer Type Annual mean costs for children with ADHD in the inpatients data set were 10% higher for those with private payers and 19% higher in the outpatients data set. In the Health Care Financing Administration data sat, children with ADHD with public payers had higher annual mean costs and mean costs per visit.

26. Comparison of Mean (1996-1997) Total Annual Costs Between Children With ADHD and Without (Controls) by Payment Method, Gender, and Age Groups

27. Comparison of Mean (1996-1997) Total Annual Costs Between Children With ADHD and Without (Controls) by Payment Method, Gender, and Age Groups

28. Comparison of Mean (1996-1997) Total Annual Costs Between Children With ADHD and Without (Controls) by Payment Method, Gender, and Age Groups

29. Comparison of Mean (1996-1997) Total Annual Costs Between Children With ADHD and Without (Controls) by Payment Method, Gender, and Age Groups

30. Comparison of Mean (1996-1997) Total Annual Costs Between Children With ADHD and Without (Controls) by Payment Method, Gender, and Age Groups

31. Comparison of Mean (1996-1997) Total Annual Costs Between Children With ADHD and Without (Controls) by Payment Method, Gender, and Age Groups

32. Comparisons of Number of Visits The proportion of the number of visits of children with ADHD to the total number of visits in the Health Care Financing Administration data set is 4.1%, 5.9% in the inpatients data, and 4.3% in the outpatient data. These proportions are significantly greater (P<.01) than the proportion of children with ADHD in the corresponding data set.

33. Comparisons of Total Cost Table 3 shows that children with ADHD accumulated costs totaling $2,546,024 + $1,618,127 + $991,152 = $5,155,303 per year on average during 1996 and 1997. Children with ADHD used 5.6% of the $91,322,466 total cost incurred by all children in the three data sets.

34. Mean Attributable Cost of Health Care to Children With ADHD in North Dakota for 1996 and 1997 by HCFA Dataset

35. Mean Attributable Cost of Health Care to Children With ADHD in North Dakota for 1996 and 1997 by Inpatient Dataset

36. Mean Attributable Cost of Health Care to Children With ADHD in North Dakota for 1996 and 1997 by Outpatient Dataset

37. Policy Implications The total mean annual cost of care attributable to ADHD in North Dakota in 1996 and 1997 was $1.79 million.

38. Policy Implications For children with private coverage, the attributable cost of $489,344 was 27.4% of all health care costs attributable to AHDS.

39. Policy Implications The attributable cost of care for children with publicly funded care was $1,326,057 or 74.3% of the total attributable costs of care attributable to ADHD in North Dakota (see Table 4). This was 1.5% of the total cost of care for all of the children in the dataset.

40. Policy Implications Utilization measured by the number of visits per year for children in the Health Care Financing Administration data set was 3.1 visits per year for private payers versus 4.7 for public payers.

41. Policy Implications In 1997, the United States population of 85,091,200 children with a 3.9% prevalence rate for ADHD would produce a total population of 3,318,557 children with ADHD. The total annual cost of care would be $2.15 billion at an annual cost of $649 per child. This result is similar to the estimates from Chan of an annual cost of care of $2.5 billion. The attributable cost of care for ADHD was $154 per case for an annual cost of care of $511,000 in North Dakota.