Patterns and predictors of medication adherence to lipid-lowering therapy in children aged 8 to 20 years

Abstract

Background: The American Academy of Pediatrics recommends lipid-lowering therapy (LLT) for children at high risk of cardiovascular disease. However, the use of LLT in children is rare, and rates of nonadherence are unknown.

Objective: To identify patterns of use and predictors of nonadherence to LLT in children aged 8 to 20 years and the subgroup with dyslipidemia.

Methods: Commercially insured patients with a new dispensing for an LLT were included. Nonadherence was defined as a gap of >90 days between the last dispensing plus the medication days supply and the next dispensing or censoring. Descriptive statistics characterize the patterns of LLT adherence and class-specific drug switching. Kaplan-Meier curves and multivariable Cox proportional hazard models identified time to, and predictors of, nonadherence for the cohort and the dyslipidemia subgroup.

Results: Of the 8710 patients meeting inclusion criteria, 87% were nonadherent. Statins were the most common index prescription, and patients with an index statin dispensing were more likely to have multiple comorbidities and other prescription drug use. In multivariable analyses, nonadherence was inversely associated with dyslipidemia (hazard ratio [HR] = 0.61, 95% confidence interval [CI] = 0.57-0.65), chronic kidney disease (HR = 0.69, 95% CI = 0.54-0.88), higher outpatient (HR = 0.87, 95% CI = 0.77-0.98), and inpatient (HR = 0.83, 95% CI = 0.70-0.97) use. When limited to patients with dyslipidemia, nonadherence was related to age (HR = 1.21, 95% CI = 1.07-1.38) and obesity (HR = 1.23, 95% CI = 1.02-1.49).

Conclusions: Despite recommendations to begin continuous treatment early for high-risk children, nonadherence to LLT is frequent in this population, with modestly higher adherence in children with dyslipidemia.

Keywords: Dyslipidemia; Medication adherence; Pediatrics; Pharmacoepidemiology.

Conflict of interest statement

The other authors have no conflicts of interest relevant to this article to disclose.

Copyright © 2016 National Lipid Association. Published by Elsevier Inc. All rights reserved.

Figures

Figure 1. Timeline of LLT therapy illustrating definition of treatment non-adherence

T1 represents the date of the index prescription. At T32 the patient refills the prescription, leaving a 2 day gap in the end of the first prescription and start of the second. However, because this gap is less than 90 days the patient is not considered to have had an episode of non-adherence. The patient then fills the next prescription at T55, 7 days earlier than the end of the 2nd prescription at T62. This overlap of seven days is then added to the 30 days supply and the end of covered treatment days is now T92(T55 + 7 days of overlap + 30 day supply). The next prescription is filled at T200, which is more than 90 days from the end of the last covered day of treatment (T92) and thus the patient is considered to be non-adherent on day 92.

Figure 2

Cumulative percent of patients with an episode of medication non-adherence lasting at least 90 days stratified by (A) A diagnosis of dyslipidemia (B) The index dispensing’s class of LLT (C) the type of non-statin LLT index dispensing among patients whose index dispensing was a non-statin (D) The type of statin index dispensing among patients whose index dispensing was a statin.