Beta-blocker prescription adherence of children and young people with long QT syndrome: a retrospective cohort study

BACKGROUND: Beta blocker non-adherence is a key factor in precipitating cardiac events in patients affected by congenital long QT syndrome. Adherence has been examined in adults affected by congenital long QT syndrome but not in a large paediatric group. METHOD: Patients with congenital long QT syndrome types 1 and 2 were identified using a database curated by the Inherited Cardiac Conditions team in Northern Ireland. Medication adherence was reviewed by contacting the patient's GP. A medication possession ratio was then calculated for the year. Adequate adherence was defined as a ratio of ≥0.8, and ideal adherence was defined as a ratio of ≥1.0. Risk factor analysis for poor adherence was performed using multivariable binary logistic regression. RESULTS: 99 patients' data was suitable for analysis, 71 had LQT1 (78%) and 28 had LQT2 (28%). The median age of the children involved was ten years old. Over 36,135 days the median medication possession ratio of this patient group was 0.92. 56 patients (57%) had at least adequate adherence, of these 44 patients (44%) had ideal adherence. In contrast 43 patients (43%) had less than adequate adherence and of these six patients (6%) were completely non-adherent. Increased deprivation was significantly associated with "less than" ideal adherence Odds Ratio (OR) 1.2 95% confidence intervals CI (1.1-1.4). CONCLUSION: Adherence in the paediatric cohort was mostly in the "adequate range." Increased deprivation is a risk factor for "less than" ideal adherence. A small minority of patients can be identified as completely non-adherent by checking prescription records. Future studies should focus on elucidating barriers and enablers to ideal adherence in this population.