In this report, the rates for children in hawk-i diagnosed with ADHD are reported four different ways.

•  Number and rate of children with an ADHD diagnosis (by diagnosis code).

•  Number and rate of children eligible for hawk-i for at least 11 months with an ADHD diagnosis.

•  Number and rate of children with an ADHD diagnosis per 1,000 member months.

•  Number of children reported to have "problems with attention" on the survey.

For the first three analyses, hawk-i program claims and encounter data were used to identify children and adolescents between the ages of three and eighteen enrolled in the hawk-i program during calendar year 2001 as the study population. There were a total of 17,166 children enrolled for at least one month in 2001.

For the fourth analysis, data from the evaluation survey were used to evaluate changes in health status and access to care for children before and after joining the hawk-i program.

1) Number and rate of children with an ADHD diagnosis (by diagnosis code)

Of the 17,166 children enrolled for at least one month in 2001, 563 had at least one claim with a diagnosis of Attention Deficit Disorder (ICD-9 314.00), Attention Deficit with Hyperactivity Disorder (ICD-9 314.01), or Hyperkinetic Conduct Disorder (ICD-9 314.9). The majority of children with a diagnosis had Attention Deficit with Hyperactivity Disorder. Table 1 provides a listing of all children enrolled for at least one month in 2001 by age and the rate of ADHD within the hawk-i enrollees.

Table 1. Children and adolescents enrolled for at least
one month by age and rate of ADHD, 2001

Age group	Number with ADHD	Total number	Percent with ADHD
3-6 years	49	4,751	1.0%
7-9 years	166	3,675	4.5%
10-12 years	185	3,492	5.3%
13-15 years	120	2,951	4.1%
16-18 years	43	2,297	1.9%
Total	563	17,166	3.3%

The rate of diagnosis of ADHD from the claims/encounter data was highest for children in the 10-12 age range, with about one in twenty children in this age group who were enrolled at any point in the year having received treatment for a diagnosis of ADHD.

2) Number and rate of children eligible for at least 11 months with an ADHD diagnosis

There were 4,947 children enrolled for at least 11 months in calendar year 2001. These children all had approximately the same amount of time in which to have received a diagnosis of ADHD. Table 2 provides a listing of these children by age and the rate of ADHD.

Table 2. Children and adolescents enrolled for at least
11 months by age and rate of ADHD, 2001

Age group	Number with ADHD	Total number	Percent with ADHD
3-6 years	21	1,230	1.7%
7-9 years	72	1,039	6.9%
10-12 years	93	1,033	9.0%
13-15 years	57	892	6.4%
16-18 years	24	753	3.2%
Total	267	4,947	5.4%

To better understand the influence of the denominator used to calculate the prevalence of ADHD in this population, Figure 1 shows the difference in rates of children diagnosed with ADHD for all those enrolled in hawk-i (for at least one month) compared to those enrolled for at least 11 months.

Figure 1. ADHD rates by age and enrollment period

 

The rate of ADHD is higher in the group of children who have been enrolled for at least 11 months. Both rates demonstrate similar patterns, however, with the highest rates being for children ages 10-12 years old. The difference between the rates may be a result of longer enrollment periods for children diagnosed with a condition, or it could be that children with shorter enrollments were not diagnosed early in their enrollment.

3) Number and rate of children with an ADHD diagnosis per 1,000 member months

Table 3 presents the number of children with ADHD per 1,000 member months. The denominator of 1,000 member months provides a standardized method for comparing populations with varying enrollment periods. Each member month is considered a unit of exposure for utilization or diagnosis. The rates across age groups are therefore standardized, and are not affected by the average child's or adolescent's length of enrollment.

Table 3. Rate of ADHD per 1,000 member months, 2001

Age group	Number of member months	Number with ADHD	Number per 1,000 member months
3-6 years	33,253	49	1.47
7-9 years	26,529	166	6.26
10-12 years	25,540	185	7.24
13-15 years	21,868	120	5.49
16-18 years	17,580	43	2.45
Total	124,770	563	4.51

This calculation again highlights that ADHD is more prevalent in 10-12 year olds.

4) Number of children with "problems with attention" reported on the survey

Figure 2 shows the survey results for the number of children whom parents reported as having had "attention problems" for the previous three months. As with the encounter data, the highest rates were reported for children ages 10-12 (13%); however, the rate for children 7-9 was also 13%.

Figure 2. Percent of children with "attention problems"
reported on the survey

Baseline demographic information regarding children with a diagnosis of ADHD

The rates of children who received a service with a diagnosis of ADHD were further evaluated to determine if differences exist by:

•  Age and gender of the child

•  Gender and race of the child