Adherence to treatment amongst children and adolescents with ADHD may be influenced by parental biases (Coletti et al. 2012), provision of adequate supervision, development of once-daily medication formulations and dose schedule (Swanson 2003); however, previous research has been limited by use of specific subpopulations. The main aim of this study was to quantify rates and correlates of patient adherence to stimulant treatment for ADHD.
Patient* prescription and sociodemographic data from 1 January 2015 to 31 December 2016 were extracted from a systematic search of electronic medical records from the Partners HealthCare Research Patient Data Registry of Massachusetts General Hospital, Boston, MA, USA. Patients were classed as adherent to treatment if the first (index) prescription was refilled in such time that the child was considered consistently medicated.† Patients’ zip codes were used to determine the median incomes of the towns in which they lived, and to categorise patients as either lower (median income <$61,391), middle (>$61,391 to <$89,271) or upper (>$89,271) class.
In total, 2206 children and adolescents with prescriptions for stimulant medication were identified; a putative ADHD diagnosis was confirmed for 1355 (61%) patients. The study definition of treatment adherence was met by 1023 (46%) patients.
- Patients who were female (42% vs 48%; p = 0.009), Caucasian (45% vs 51%; p = 0.01) or aged ≥12 years (45% vs 49%; p = 0.04) were significantly less likely to adhere to medication compared with males, non-Caucasians and patients aged <12 years, respectively.
- Additionally, patients from upper-class (44%) or middle-class (45%) backgrounds were less likely to adhere to treatment than those from lower-class (50%) backgrounds (p = 0.03).
- Patients taking amfetamines were also less likely to adhere to treatment than those taking methylphenidate (42% vs 48%, respectively; p = 0.02).
- Patients who received their prescriptions from a psychiatric clinic rather than a non-psychiatric clinic were significantly more likely to be adherent to treatment (52% vs 43%, respectively; p = 0.001).
- There was no statistically significant difference in adherence to treatment between groups with different primary languages (English [46%] vs not English [49%]; p = 0.51) and medication formulations (short- [44%] vs long-acting [47%]; p = 0.29).
A multivariable logistic regression model was constructed in order to identify socioeconomic, demographic and clinical factors that could predict treatment adherence. Sex, age and prescription source were found to be significantly associated with adherence to treatment. Male patients (odds ratio [OR] 1.23; 95% confidence interval [CI] 1.01–1.49; p = 0.04) were more likely to adhere to treatment than females, as were those with prescriptions from a psychiatric service (OR 1.54; 95% CI 1.24–1.91; p < 0.001) versus prescriptions from a non-psychiatric service. Whereas, older patients were less likely to adhere to treatment (OR 0.97; 95% CI 0.94–0.99; p = 0.03); however, a low area-under-the-curve statistic of 0.57 reported for the model indicated unreliability.
This study had several limitations. The authors acknowledged that their definition of adherence to treatment may have differed from other studies. Moreover, the time of year at which results were collected was not considered, and some paediatric patients may not take their medication during the summer. The authors also acknowledged that their findings may not be generalisable, as all patients were from a single healthcare organisation in Boston, MA, USA.
The authors concluded that, although small, statistically significant differences in age, sex, economic class, medication type and prescription source were identified between patients who did or did not adhere to ADHD stimulant medication. These data suggest that low adherence to stimulants in ADHD may affect all ages, both sexes and all economic class strata.
*Records from children aged 4–17 years prescribed amfetamines or methylphenidate (short- or long-acting formulations) between 1 January 2015 and 31 December 2016 were included in the study. The following formulations of stimulants were accepted: amfetamine/dextroamfetamine, dextroamfetamine or lisdexamfetamine, dexmethylphenidate or methylphenidate
†A patient was defined adherent if the first (index) prescription was refilled in one of the following ways: a single index prescription was followed by a second prescription within 90 days; index prescriptions post-dated by 2 months (i.e. two prescriptions in the system with the same prescribing date for medications of the same dose, formulation and type) were followed by a third prescription within 31 and 120 days after the date of index prescription; or index prescriptions post-dated by 3 months (i.e. three prescriptions in the system with the same prescribing date for medications of the same dose, formulation and type) were followed by a fourth prescription issued between 61 and 150 days after the date of the index prescription
Coletti DJ, Pappadopulos E, Katsiotas NJ, et al. Parent perspectives on the decision to initiate medication treatment of attention-deficit/hyperactivity disorder. J Child Adolesc Psychopharmacol 2012; 22: 226-237.
Biederman J, Fried R, DiSalvo M, et al. Evidence of low adherence to stimulant medication among children and youths with ADHD: an electronic health records study. Psychiatr Serv 2019; Epub ahead of print.
Swanson J. Compliance with stimulants for attention-deficit/hyperactivity disorder: issues and approaches for improvement. CNS Drugs 2003; 17: 117-131.