Michelle Steele and Ray M. Merrill, PhD, MPH, Department of Health Science

Introduction

Attention deficit hyperactivity disorder is a known disorder that mainly effects children but can carry on into adulthood. It is characterized by difficulty focusing, sustaining attention, and controlling behaviors. These characterizations can cause a person with ADHD to have a more difficult time accomplishing certain tasks. In a study involving medical claims data over the years 1998 through 2005, Attention deficit hyperactivity disorder (ADHD) was shown to increase the risk of several types of injury (Merrill). The study found that ADHD was associated with more severe and frequent injuries, but that medication had a protective effect against injury among patients. The purpose of the current study was to update frequencies and patterns of ADHD and selected types of medication use in our cohort. We then looked at how ADHD and medication influenced the rate of particular injuries. Focus will be on how selected types of medication may influence the risk of injury among ADHD patients according to the sex, age, and time variables.

Methodology

A retrospective cohort study was conducted with medical claims data from the Deseret Mutual Benefit Administrators (DMBA). DMBA is a health insurance company for employees of the Church of Jesus Christ of Latter-day Saints. The database includes information on the employees, their spouses and dependent children. Automated claims records were examined from January 1, 2001 to December 31, 2012 and used the International Classification of Diseases, 9th Revision, Clinical Modification codes to define injuries and ADHD. Incidence rates of ADHD were based on cases divided by person-years. A total of 973,161 person-years are represented in the study. A person was considered to be a case if in a given year they had a physician clam for ADHD and/or a prescription for a psycho-stimulant or Strattera. Counts, proportions, rates, and rate ratios were used to describe the results

Results

The rate of Attention Deficit Hyperactivity Disorder (ADHD) significantly increased from 2001 through 2012, was significantly greatest in the age range 10-17, followed by 18-24, and then 0-9, and was significantly greater in males than females. The incidence rate of experiencing an injury (per 100,000 person-years) was 226.1 for individuals with ADHD and 158.4 for those without the disorder. The rate ratio was 1.43 (95% CI = 1.38- 1.47), 1.36 (1.31-1.40) after adjusting for age, sex, and year. Increased risk of injury among ADHD patients was observed across selected types of injury. Among people with ADHD, the rate of injury was significantly lower for those who took medication compared with those who did not (by 20%, rate ratio = 0.80, 95% CI = 0.76-0.83, adjusted for age, sex, and year). Although the medications are seen to be generally protective against injury among ADHD patients, Adderall increased the risk of injury among ADHD patients in the age range 25 through 44 (by 18%, rate ratio = 1.18, 95% CI = 1.02-1.38).

Discussion

This study was able to provide information related to ADHD and medications. The risk of injury was seen to exist related to various types of injuries. The different types of injuries decreased when a person with ADHD was taking medication to control their ADHD. The exception to this was Adderall which in the case of those 25 to 44, increased risk of injury. This increase in risk of ADHD is associated with several things with potential to predict injuries such as family conflict, familial instability and psychiatric disorders. These relationships were not able to be looked at, however these factors could explain or confound for the association between ADHD and injury. Related to Adderall, the increased risk of injury could be due to the medication and not due to having ADHD. Adderall has shown increased risk of certain adverse reactions including accidental injury, fatigue and dizziness. These side effects all have the potential to increase injuries. Other limitations or confounding factors could be seen in this study and need to be further researched.

Conclusion

This study showed that ADHD increased since 2001. Those with ADHD have an increased risk of injury. Those taking medication for their ADHD showed a decreased rate of injury with the exception of Adderall, which showed an increased rate of injury in patients 25-44. Intervention of those with ADHD who are not currently medicated and those who are currently medicated with Adderall could have warranted effects on injury prevention.

References

• International Classification of Diseases, 9th Revision, Clinical Modification, 4th ed., 3 vol. U.S. Department of Health and Human Services, October 1991.
• Merrill RM, Lyon JL, Baker RK, Gren LH. Attention deficit hyperactivity disorder and increased risk of injury. Adv Med Sci. 2009;54(1):20-6.