[Show abstract][Hide abstract] ABSTRACT: Little is known about longitudinal changes in drug utilization in attention-deficit/hyperactivity disorder (ADHD).
To describe longitudinal trends in ADHD drug utilization and explore demographic differences among youths eligible for a large Southern state Medicaid program.
A cross-sectional and longitudinal analysis of 10 years of claims data for all Medicaid beneficiaries younger than 20 years of age with 6 months or more of continuous insurance (N = 2,131,953) was conducted. Annual prevalence, incidence, and persistence in ADHD medication use (stimulants and atomoxetine) were estimated based on pharmacy claims and clinician-reported ADHD diagnosis.
ADHD prevalence increased 1.70-fold (95% CI 1.67 to 1.73) from 3.10% (21,904 of 705,573 beneficiaries) in fiscal year 1995-1996 to 5.27% (41,681 of 790,338) in 2003-2004, paralleled by a 1.84-fold (95% CI 1.81 to 1.87) increase in drug use to 4.63%. In 2003-2004, 0.89% of youths were diagnosed and newly started on drugs, reflecting a 1.38-fold (95% CI 1.33 to 1.43) increase over 1995-1996. One in five white males between the ages of 10 and 14 years (19.24%; 95% CI 18.81 to 19.67) received ADHD medication in 2003-2004. Males continued to be more likely diagnosed and treated than females (prevalence ratio [PR] in 2003-2004 = 2.96; 95% CI 2.90 to 3.03 vs 3.82; 95% CI 3.69 to 3.96 in 1995-1996), as were whites when compared with Hispanics (PR in 2003-2004 = 2.65; 95% CI 2.57 to 2.73 vs 3.78; 95% CI 3.57 to 3.99 in 1995-1996) and blacks (PR in 2003-2004 = 1.81; 95% CI 1.76 to 1.85 vs 2.00; 95% CI 1.93 to 2.07 in 1995-1996). The most common starting age throughout the study period was 5-9 years, with 2.45% (95% CI 2.37 to 2.52) new ADHD drug users in 2003-2004, but largest increases in prevalence were observed in adolescents 15-19 years of age, with 2.47% (95% CI 2.38 to 2.55) in 2003-2004 compared with 0.45% (95% CI 0.41 to 0.49) in 1995-1996. Medication persistence varied, with only 49.9% (95% CI 49.4 to 50.5) of new users receiving drugs after 1 year, with yet another 17.2% (95% CI 16.4 to 18.0) continuing for 5 years or more.
ADHD drug utilization continues to increase due to steady increases in diagnosis and chronic use of the drugs over several years. While racial, ethnic, and sex differences persist, the age distribution of drug users has shifted toward older children. These findings emphasize the need for studies that analyze determinants of treatment as well as outcomes, both benefits and risks, associated with long-term medication use.
Preview · Article · Feb 2008 · Annals of Pharmacotherapy
[Show abstract][Hide abstract] ABSTRACT: Case reports have raised concerns about the risk of cardiac events associated with central nervous system stimulants for the treatment of attention-deficit/hyperactivity disorder.
This was a retrospective cohort study that used 10 years (July 1994 to June 2004) of Florida Medicaid claims data cross-linked to Vital Statistics Death Registry data. The cohort was composed of all youth 3 to 20 years old who were newly diagnosed with attention-deficit/hyperactivity disorder. Each month of follow-up was classified according to stimulant claims (methylphenidate, amphetamines, and pemoline) as current use (active stimulant claim), former use (time after periods of current use), or nonuse (time preceding the first stimulant claim, including follow-up of youth who were never exposed to stimulants). The study's end points were (1) cardiac death, (2) first hospital admission for cardiac causes or (3) first emergency department visit for cardiac causes. Risks were compared with time-dependent Cox regression analysis adjusting for various cardiac risk factors.
During 124,932 person-years of observation (n = 55,383), 73 youth died, 5 because of cardiac causes. No cardiac death occurred during 42,612 person-years of stimulant use. Hospital admissions for cardiac cause occurred for 27 children (8 during stimulant use, 11 during 35,671 person-years of former use, and 8 during 46,649 person-years of nonuse); and 1091 children visited the emergency department for cardiac causes (8.7 per 1000 person-years). Current stimulant use was associated with a 20% increase in the hazard for emergency department visits when compared with nonuse. No increased risk was found for periods of former use when compared with nonuse.
Incidence rates of cardiac events requiring hospitalization were small and similar to national background rates. Stimulants were associated with an increase in cardiac emergency department visits. More evidence is needed that addresses the long-term risk/benefit of the various treatment options and the effect of other cardiac risk factors and comedications.