Pattern of Use of Psychotropic Medication in Patients with Autism Spectrum Disorder in the United States
Objectives: The objectives of this study were to investigate the pattern of use of psychotropic medications in terms of length of treatment (LOT) as well as factors associated with psychotropic medication polypharmacy among commercially insured patients with ASD in the United States.
Methods: This retrospective observational study utilized administrative claims data based on multiple commercial health plans in the United States (MarketScan® Commercial Database). ASD patients of all ages were identified by having at least two ASD diagnoses (ICD-9-CM code of 299.0x, 299.8x, or 299.9x) in the database between 2000 and 2013, and having at least one of the ASD diagnoses during the year of 2013, i.e. the year of the interest for this analysis. A total of 38,071 ASD patients were identified. Polypharmacy was defined as the concurrent use of two or more psychotropic medications in at least two drug classes for 30 consecutive days or longer. LOT was defined for each medication class as the sum of supply days for medications in the class; a day supplied with multiple drugs within the same class was counted as one day. Psychotropic drug classes of interest were antidepressants, stimulants, antipsychotics/tranquilizers, anticonvulsants, anxiolytics/sedatives/hypnotics, and hypotensive agents (limited to clonidine and guanfacine). Mental disorders of interest included epilepsy, sleep disturbances, attention-deficit disorder (ADD), anxiety disorder, depression, bipolar disorder, schizophrenia, and conduct disorder.
Results: The age in the cohort ranged from 3 to 65 years. For most of the drug classes investigated, patients were given medications for >200 days on average in 2013, regardless of the presence of concomitant mental conditions. However, for anxiolytics/sedatives/hypnotics, LOT was shorter (<100 days). Among patients who received psychotropic medications, mean and median LOT increased with age. Of all ASD patients, 35% had psychotropic polypharmacy. Polypharmacy was rare among patients <5 years of age (2%), but was 49% for patients aged 18 years and older. Although polypharmacy was common among patients with mental comorbidities (49%), many patients (17%) with none of the conditions of interest had polypharmacy. Polypharmacy was most commonly observed among patients with bipolar disorder (82%), followed by patients with schizophrenia (76%) and depression (62%). Adjusted multivariate logistic regression indicated that patients who were older, and those who had a claim for any of the mental conditions of interest, were more likely to have received psychotropic polypharmacy.
Limitations: Diagnosis of ASD or any of the comorbidities of interest was based on claims data. Reasons for initiating treatment with psychotropic medications cannot be assessed.
Conclusions: Our study showed that psychotropic polypharmacy was associated with older age and comorbid mental conditions. Almost a fifth of ASD patients without mental comorbidities received polypharmacy, despite limited evidence supporting the safety and effectiveness of these combinations.