Adherence to long-term therapies in cystic fibrosis: a French cross-sectional study linking prescribing, dispensing, and hospitalization data

Abstract

Background

Cystic fibrosis (CF) is a life-shortening genetic condition that usually affects several organs and involves significant treatment burden. Adherence to medication is important for successful CF management.

Objective

To describe medication adherence according to age, therapeutic class, and pharmaceutical form in adults and children followed in four regional CF centers in France.

Methods

We conducted a cross-sectional study with non-transplanted patients followed in two adult and two pediatric centers during 2015 who were covered by the French National Health Insurance (NHI). Sociodemographic, clinical, hospitalization, and prescription data were collected from patient medical records. Medication dispensations were extracted from the regional French NHI database. Adherence was calculated over 12 months using continuous medication availability (CMA) accounting for dose adjustments and hospitalizations. Drug-specific CMA was computed in R with the AdhereR package for each medication prescribed more than 3 months, which was averaged to obtain a composite CMA score (cCMA) for all treatments and per therapeutic class as well as pharmaceutical form for each patient.

Results

A total of 228 patients were included. The number of chronic medications increased with age (r=0.50, p<0.001): a median of 7 medications per patient were prescribed. The mean±SD cCMA was significantly different between age groups (p=0.0098): it was 0.71±0.20 for the 0–5 years age group, 0.73±0.16 for 6–11 years, 0.64±0.17 for 12–17 years, 0.57±0.23 for 18–25 years, and 0.65±0.20 for the over 25 years age group. cCMA varied significantly according to pharmaceutical forms: the mean±SD cCMA was 0.70±0.21 for oral medications and 0.54±0.28 for inhaled medications (p<0.001).

Conclusion

This study suggests that adherence to medication regimens in CF patients remains suboptimal and varies substantially between age groups and pharmaceutical forms. These variations in adherence should be considered when developing effective strategies to improve adherence.

Keywords:

• cystic fibrosis
• chronic treatment
• medication adherence
• administrative claims data
• prescription data

Supplementary material

Table S1 CF therapeutic medications used in long term by patients of the study

Acknowledgments

We thank Neziha Bensalem, Laetitia Bouveret, Sophie Hommey, Stephanie Polazzi, and Marie Perceval for their technical advice and their contribution during the implementation of the study and data collection. We also thank the Direction régionale du service médical Rhône-Alpes de la Caisse nationale d’Assurance maladie des travailleurs salariés (DRSM), the regional directorate of the French National Health Insurance for access to administrative claims data of its regional reimbursement database (Extraction, Recherches, Analyses pour un Suivi Medico-Economique, ERASME). This work was funded by the association Vaincre la Mucoviscidose (VLM) (RC20150501406).

Author contributions

MV, PC, ADenis, ADima, ID, and ST contributed to the study concept and design and SPB, HR, MV and ST participated in the conduct of the study. All authors contributed to the acquisition of data for the work. HR, MV, ADenis, and SA contributed to the data analysis, and HR, MV, ST, SA, QR, ADenis, ADima, and ID contributed toward drafting. All authors contributed toward critically revising the paper, gave final approval of the version to be published, and agree to be accountable for all aspects of the work.

Disclosure

Alexandra Lelia Dima report grants and non-financial support from Respiratory Effectiveness Group, outside the submitted work. The authors report no other conflicts of interest in this work.