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Abstract
Objective The present study investigated the effects of switching to different products of the same off-patent active substance (brand name or generic) on therapy discontinuation or substitution with another molecule of the same class, in patients with cardiovascular disease treated with statins and antihypertensives in a ‘real-world’ setting.
Design A retrospective cohort study in a ‘real-world’ setting.
Setting Analysis of data performed by integrating administrative databases that included approximately two million individuals who are assisted by the National Health System from three Local Health Units located in three different regions of Italy.
Participants All patients aged ≥18 years with at least one prescription of simvastatin, ramipril or amlodipine in the period 1 January to 31 December 2010 were included and followed up for 2 years.
Main outcome measures Prescription refills occurring during follow-up were evaluated. Frequency of discontinuation of therapy or substitution with another molecule of the same class (eg, from simvastatin to a different statin) during follow-up was identified.
Results During follow-up, therapy discontinuation or substitution was found to be more frequent in patients switching to a different product of the same active substance compared with non-switching patients (11.5% vs 10.8% and 22.2% vs 20.8% (p=0.002), respectively, in the simvastatin group; 4.0% vs 3.5% and 24.6% vs 22.7% (p<0.001), respectively, in the amlodipine group). In the ramipril group, 8% of patients undertook a therapy substitution to another molecule; no trend towards a lower percentage of substitution was observed in the non-switching group, while 18% of patients discontinued treatment, with a significant difference in favour of patients not switching. These findings were partially confirmed by multivariate analysis.
Conclusions Switches among products of the same active substance are quite common in patients with cardiovascular disease. Our study suggests that switching may expose patients to a higher risk of therapy discontinuation or substitution.
- Simvastatin
- Amlodipine
- Ramipril
- Switching
- Adherence to treatment
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Footnotes
Contributors LDE, FS, DS conceived and designed the study. LDE, DS, SB and EDE analysed the data. LDE, FS and DS wrote the paper. All authors revised and approved the final version.
Funding This research received no specific grant from any funding agency in the public, commercial or not-for-profit sectors.
Competing interests FS has served as consultant and had speaking engagements to pharma companies marketing cardiovascular drugs and has been compensated for travel and time spent on research and lectures. All authors declare no support from any organisation for the submitted work.
Ethics approval For this type of study, formal consent is not required. However, to guarantee patient privacy, no personal identifiers were provided to the researchers. According to the Italian law for confidentiality of data, the study was notified to the Ethic Committees of each local health unit.
Provenance and peer review Not commissioned; externally peer reviewed.
Data sharing statement No additional data are available.