Who benefits from fixed-dose combinations? Two-year statin adherence trajectories in initiators of combined amlodipine/atorvastatin therapy
Corresponding Author
Andrea L. Schaffer
Centre for Big Data Research in Health, University of New South Wales, Sydney, Australia
Correspondence
A. Schaffer, Centre for Big Data Research in Health, Level 1, AGSM Building (G27), University of New South Wales, Sydney NSW 2052, Australia.
Email: [email protected]
Search for more papers by this authorNicholas A. Buckley
Sydney Medical School, University of Sydney, Camperdown, Australia
Search for more papers by this authorSallie-Anne Pearson
Centre for Big Data Research in Health, University of New South Wales, Sydney, Australia
Menzies Centre for Health Policy, University of Sydney, Camperdown, Australia
Search for more papers by this authorCorresponding Author
Andrea L. Schaffer
Centre for Big Data Research in Health, University of New South Wales, Sydney, Australia
Correspondence
A. Schaffer, Centre for Big Data Research in Health, Level 1, AGSM Building (G27), University of New South Wales, Sydney NSW 2052, Australia.
Email: [email protected]
Search for more papers by this authorNicholas A. Buckley
Sydney Medical School, University of Sydney, Camperdown, Australia
Search for more papers by this authorSallie-Anne Pearson
Centre for Big Data Research in Health, University of New South Wales, Sydney, Australia
Menzies Centre for Health Policy, University of Sydney, Camperdown, Australia
Search for more papers by this authorAbstract
Purpose
We compared statin adherence in individuals initiating combined amlodipine/atorvastatin therapy as a fixed-dose (FDC) or free combination and identified subgroups benefiting most from FDCs.
Methods
We used a 10% sample of Australian Pharmaceutical Benefits Scheme dispensing data (2005-2015) to identify individuals initiating amlodipine and atorvastatin as an FDC (n = 3996) or free combination (n = 5434), with or without prior statin dispensing. We measured the proportion of days covered in each 30-day period over 24 months and classified patterns of statin adherence using group-based trajectory models. We identified predictors of adherence trajectories using logistic regression.
Results
The median age was 71 years, and 53% were female. We identified 4 patterns of statin adherence: near-perfect adherence (n = 5383), good adherence (n = 1893), declining adherence (n = 1247), and early nonadherence (n = 907). Compared with the free combination, FDC initiators were more likely to have near-perfect adherence if they were previously statin adherent irrespective of amlodipine dose (amlodipine 5 mg: OR = 1.61, 95% CI 1.38-1.87; amlodipine 10 mg: OR = 2.39, 95% CI 1.63-3.51) or they were previously statin nonadherent and initiated on the 5 mg amlodipine dose (OR = 1.87, 95% CI 1.50-2.32). Statin-naïve individuals initiating on the FDC with 10 mg amlodipine were less likely to have near-perfect adherence (OR = 0.60, 95% CI 0.41-0.88) and more likely to have early nonadherence (OR = 1.73, 95% CI 1.17-2.55).
Conclusions
The amlodipine/atorvastatin FDC was associated with greater statin adherence among prevalent statin users, and individuals who initiated on lower amlodipine doses. The FDCs did not improve adherence in statin-naïve individuals and in some cases resulted in poorer adherence.
Supporting Information
| Filename | Description |
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| pds4342-sup-0001-Data_S1.pdfPDF document, 246.7 KB |
Appendix S1: Results of logistic regression models predicting membership in each statin adherence trajectory compared with all other trajectories combined |
Please note: The publisher is not responsible for the content or functionality of any supporting information supplied by the authors. Any queries (other than missing content) should be directed to the corresponding author for the article.
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