Winterstein 2009.

Methods	A 10 year retrospective cohort design evaluating the cardiac safety of methylphenidate and amphetamine salts
Participants	Number of participants screened: 2,131,953 Number of participants included: 30,576 Number of participants included in methylphenidate arm: 18,238 Number of participants followed up: 18,238 Number of withdrawals: 0 Diagnosis of ADHD: ICD‐9 (subtype: not stated) Age: mean 8.5‐9.2, range: 3‐20 years old IQ: not stated Sex: 13332 males, 4906 females Methylphenidate‐naïve: 100% Ethnicity: white: 44‐48.2%, African American: 31.6‐34.7%, Hispanic: 14.4‐15.5% Country: USA Comorbidity: circulatory disease (3.5%) Comedication: bronchodilators 15.5‐16.3%, antidepressants 14‐16.4%, antipsychotics 8.2% Sociodemographics: not stated Inclusion criteria Between 3‐20 years ≥ 1 inpatient or outpatient claim for ADHD defined by ICD‐9 Newly started on methylphenidate or amphetamine salts Exclusion criteria Eligibility ending Diagnosis of malignant neoplasm Turning 21 years Switching from 1 drug class to the other Starting to use drugs from both categories concomitantly When outcome of interest has occurred
Interventions	Methylphenidate type: not stated Methylphenidate dosage: not stated Administration schedule: not stated Duration of intervention: not stated Treatment compliance: not stated
Outcomes	Serious adverse events: Data assembled from the Florida Medicaid fee‐for‐service programme Cardiac event defined as a first emergency department (ED) visit for cardiac disease or symptoms: myocardial infarction, stroke, hypertensive disease (excluding malignant causes), angina, aortic or thoracic aneurysm, arrhythmias, syncope, or tachycardia or palpitation ED visits were chosen as clinical end point because they occur more frequently than hospital admissions or cardiac death and provided the best power to detect even subtle difference between drugs
Notes	Sample calculation: no Ethics approval: not stated Funding: funded in part by the Florida Department of Health, Agency for Healthcare Administration Vested interests/authors' affiliations: Dr Gerhard was in part funded by a grant from the Agency for Healthcare Research and Quality Key conclusions of the study authors: exposure to methylphenidate and amphetamines salts showed similar risk for cardiac ED visits Exclusion of methylphenidate non‐responders/children who have previously experienced adverse events on methylphenidate: no Supplemental information requested through personal email correspondence with the authors in January 2014 with no reply