Association between methylphenidate use and long-term cardiovascular risk in paediatric patients with attention deficit and hyperactivity disorder.

Background: There have been concerns about the potential cardiovascular (CV) adverse effects associated with methylphenidate (MTH) use. However, only limited evidence exists on the long-term safety of MTH.

Objective: To evaluate whether MTH use is associated with long-term CV risk.

Methods: This was a retrospective cohort study using 2003-2017 data from the Health and Welfare Database in Taiwan. Patients newly diagnosed with attention deficit and hyperactivity disorder (ADHD) and between 3 and 18 years of age were included. Two treatment statuses were assessed: initial treatment ≥7 days and ≥180 days. Patients treated with MTH were compared with those receiving non-medication therapy. One-to-one propensity score matching was used to balance between-group differences. Study outcomes included major CV events, chronic CV disease, cardiogenic shock and all-cause mortality. Cox proportional hazard models were used to estimate HRs between the two groups.

Results: We began with 307 459 patients with ADHD. After exclusion, 224 732 patients were included in the final cohort. The results showed that compared with non-ADHD medication users, patients who were treated with MTH for more than 7 days had a similar risk of major CV events (HR 0.85, 95% CI 0.72 to 0.99; p=0.040). Identical trends were found in groups who were treated for more than 180 days (HR 0.83, 95% CI 0.69 to 1.00; p=0.050). The results of the sensitivity analyses were consistent with the main analyses across all groups and individual outcomes.

Conclusion: Short-term MTH use did not increase CV risk among patients with ADHD. More evidence on long-term MTH use and risk of cardiogenic shock and death is warranted.