Comparison of Medication Adherence and Treatment Persistence between New Oral Anticoagulant and Warfarin among Patients.

INTRODUCTION: This study aimed to compare medication adherence and treatment persistence of patients on warfarin versus rivaroxaban in Singapore. A secondary objective was to identify significant covariates influencing adherence. MATERIALS AND METHODS: A retrospective cohort study was conducted where data from September 2009 to October 2014 was retrieved from the hospital electronic databases. Prescription records of rivaroxaban patients with 3 months or more of continuous prescription were extracted and compared against those of patients on warfarin. Primary outcome of adherence was determined based on the medication possession ratio (MPR), while treatment persistence was determined by outpatient clinic appointment gaps. RESULTS: A total of 94 rivaroxaban and 137 warfarin users were analysed by complete case analysis. The MPR of warfarin patients was lower than rivaroxaban patients by 10% (95% CI, 6.4% to 13.6%; P <0.0001). Also, there were more warfarin patients who had gaps in treatment persistence compared to those prescribed rivaroxaban (8.0% vs 1.1%; P = 0.03). Significant factors affecting medication adherence were age and duration of anticoagulant use. For every 10-year increase in age, MPR increased by 1.7% (95% CI, 0.7% to 2.8%). Similarly, for every year increase in duration of use, MPR increased by 1.8% (95% CI, 0.6% to 3.0%). Race, gender, concomitant medication and type of residence were not found to be significant covariates in the multivariable analysis. CONCLUSION: Patients on rivaroxaban are likely to be more adherent to their prescribed oral anticoagulant with increasing age and duration of treatment influencing adherence.

Direct microneedle array fabrication off a photomask to deliver collagen through skin.

PURPOSE: To fabricate microneedle arrays directly off a photomask using a simple photolithographical approach and evaluate their potential for delivering collagen. METHODS: A simple photolithographical approach was developed by using photomask consisting of embedded micro-lenses that govern microneedle geometry in a mould free process. Microneedle length was controlled by use of simple glass scaffolds as well as addition of backing layer. The fabricated arrays were tested for their mechanical properties by using a force gauge as well as insertion into human skin with trypan blue staining. Microneedle arrays were then evaluated for the delivery of fluorescent collagen, which was evaluated using a confocal laser scanning microscope. RESULTS: Microneedles with sharp tips ranging between 41.5 ± 8.4 µm and 71.6 ± 13.7 µm as well as of two different lengths of 1336 ± 193 µm and 957 ± 171 µm were fabricated by using the photomasks. The microneedles were robust and resisted fracture forces up to 25 N. They were also shown to penetrate cadaver human skin samples with ease; especially microneedle arrays with shorter length of 957 µm penetrated up to 72% of needles. The needles were shown to enhance permeation of collagen through cadaver rat skin, as compared to passive diffusion of collagen. CONCLUSIONS: A simple and mould free approach of fabricating polymeric microneedle array is proposed. The fabricated microneedle arrays enhance collagen permeation through skin.