Abstract
Background
Adherence to asthma and chronic obstructive pulmonary disease (COPD) treatment has been shown to depend on patient-level factors, such as disease severity, and medication-level factors, such as complexity. However, little is known about the impact of prescription charges – a factor at the health care system level. This study used real-life data to investigate whether co-payment affects adherence (implementation and persistence) and disease outcomes in patients with asthma or COPD.
Methods
A matched, historical cohort study was carried out using two UK primary care databases. The exposure was co-payment for prescriptions, which is required for most patients in England but not in Scotland. Two comparison cohorts were formed: one comprising patients registered at general practices in England and the other comprising patients registered in Scotland. Patients aged 20–59 years with asthma, or 40–59 years with COPD, who were initiated on fluticasone propionate/salmeterol xinafoate, were included, matched to patients in the opposite cohort, and followed up for 1 year following fluticasone propionate/salmeterol xinafoate initiation. The primary outcome was good adherence, defined as medication possession ratio ≥80%, and was analyzed using conditional logistic regression. Secondary outcomes included exacerbation rate.
Results
There were 1,640 patients in the payment cohort, ie, England (1,378 patients with asthma and 262 patients with COPD) and 619 patients in the no-payment cohort, ie, Scotland (512 patients with asthma and 107 patients with COPD). The proportion of patients with good adherence was 34.3% and 34.9% in the payment and no-payment cohorts, respectively, across both disease groups. In a multivariable model, no difference in odds of good adherence was found between the cohorts (odds ratio, 1.04; 95% confidence interval, 0.85–1.27). There was also no difference in exacerbation rate.
Conclusion
There was no difference in adherence between matched patients registered in England and Scotland, suggesting that prescription charges do not have an impact on adherence to treatment.
Acknowledgments
The authors thank Derek Skinner for data extraction, Martina Stagno d’Alcontres and Susannah Thornhill for medical writing, and Lakmini Bulathsinhala for performing quality checks of statistical code and study support. This study was funded by TEVA Europe.
Author contributions
BV, JFMvB, DR, MM, and DBP developed the research question. JV and DBP developed the study design. JV conducted the data preparation and analyses. LML drafted the manuscript. All authors were involved in the interpretation of the data and the critical review and revision of the manuscript. All authors read and approved the final manuscript.
Disclosure
JV and LML are employed by Observational & Pragmatic Research Institute Pte Ltd, Singapore, which receives funding from UK National Health Service, British Lung Foundation, Aerocrine, AKL Ltd, Almirall, AstraZeneca, Boehringer Ingelheim, Chiesi, Eli Lilly, GlaxoSmithKline, Meda, Merck, Mundipharma, Napp, Novartis, Orion, Pfizer, Respiratory Effectiveness Group, Takeda, Teva Pharmaceuticals, and Zentiva. JFMvB’s institution has received study grants from GlaxoSmithKline, Novartis, AstraZeneca, and Boehringer Ingelheim and consultancy fees from AstraZeneca. DR has received personal fees for lectures from Chiesi, AstraZeneca, Takeda, Boehringer Ingelheim, Novartis, and Teva and for advisory boards from Teva, Chiesi, Boehringer Ingelheim, and Novartis. MM has received speaker fees from Boehringer Ingelheim, AstraZeneca, Chiesi, GlaxoSmithKline, Menarini, Teva, Grifols, and Novartis and consulting fees from Bayer Schering, Boehringer Ingelheim, GlaxoSmithKline, Gebro Pharma, CLS Behring, Cipla, MediImmune, Mereo Biopharma, Teva, Novartis, and Grifols. DBP has a board membership with Aerocrine, Almirall, Amgen, AstraZeneca, Boehringer Ingelheim, Chiesi, Meda, Mundipharma, Napp, Novartis, and Teva; received consultancy fees from Almirall, Amgen, AstraZeneca, Boehringer Ingelheim, Chiesi, GlaxoSmithKline, Meda, Mundipharma, Napp, Novartis, Pfizer, Teva, and Zentiva; grants/grants pending with UK National Health Service, British Lung Foundation, Aerocrine, AstraZeneca, Boehringer Ingelheim, Chiesi, Eli Lilly, GlaxoSmithKline, Meda, Merck, Mundipharma, Novartis, Orion, Pfizer, Respiratory Effectiveness Group, Takeda, Teva, and Zentiva; received payments for lectures/speaking from Almirall, AstraZeneca, Boehringer Ingelheim, Chiesi, Cipla, GlaxoSmithKline, Kyorin, Meda, Merck, Mundipharma, Novartis, Pfizer, SkyePharma, Takeda, and Teva; received payment for manuscript preparation from Mundipharma and Teva; received patents (planned, pending, or issued) from AKL Ltd.; received payment for the development of educational materials from GlaxoSmithKline, Novartis; has stock/stock options with shares in AKL Ltd, which produces phytopharmaceuticals and owns 80% of research in Real Life Ltd, 75% of the social enterprise Optimum Patient Care Ltd, and 75% of Observational & Pragmatic Research Institute Pte Ltd; received payment for travel/accommodations/meeting expenses from Aerocrine, Boehringer Ingelheim, Mundipharma, Napp, Novartis, and Teva; funding for patient enrolment or completion of research: Almirral, Chiesi, Teva, and Zentiva; is a peer reviewer for grant committees of Medical Research Council (2014), Efficacy and Mechanism Evaluation Programme (2012), and HTA (2014); and received unrestricted funding for investigator-initiated studies from Aerocrine, AKL Ltd, Almirall, Boehringer Ingelheim, Chiesi, Meda, Mundipharma, Napp, Novartis, Orion, Takeda, Teva, and Zentiva. The authors report no other conflicts of interest in this work.