Het Nederlands Platform voor Farmaceutisch Onderzoek (NPFO) presenteert onderzoek in de farmaceutische wetenschappen. De nadruk ligt op klinische toepassing zoals medicatieveiligheid, patiëntenzorg, formulering, analyse, farmacologie en casuïstiek.
Preferences of patients and pharmacists with regard to the management of drug-drug interactions: a choice-based conjoint analysis
Background
For the management of drug-drug interactions (DDI), a risk-benefit assessment should be combined with the patient’s perspective.
Objective
To investigate patients’ and pharmacists’ preferences regarding DDI management.
Design and methods
We conducted an online choice-based conjoint survey among patients and pharmacists. The choice task was about the management of a fictitious DDI: the combination of a cardiovascular drug and an antibiotic for pneumonia leading to a risk for developing muscle problems. Respondents answered twelve choice sets of two DDI-management options. The options were only described by their five characteristics (attributes) regarding risk for adverse events, benefit, and practical consequences. Each of the five attributes could have two different levels (e.g. low or high risk), which were varied over the 12 choice tasks. Data were analysed by latent class analysis in order to identify potential classes (subgroups) of respondents with similar preference patterns.
Results
The survey was completed by 298 patients and 178 pharmacists. The latent class model for both patients and pharmacists resulted in three classes. The first class of patients attached most importance to fewer adverse events (class probability 41%), the second class attached most importance to avoiding a medication switch (20%), and the third class attached most importance to blood sampling (39%). For pharmacists, the first class attached most importance to curing pneumonia (31%), the second class to avoiding a medication switch (31%), and the third class to avoiding blood sampling (38%).
Conclusion
Among patients and pharmacists diverging preferences regarding DDI management were observed. Some subgroups of respondents attached most value to risk or benefit while others attached more value to practical considerations. Awareness of existing variability in preferences among and between pharmacists and patients can contribute to shared decision making in DDI management.
Comparison between coagulation factor VIII quantified with one-stage activity assay and mass spectrometry in haemophilia A patients
Background
Haemophilia A is a hereditary bleeding disorder caused by a factor VIII (FVIII) deficiency. As biomarker, FVIII activity is used to classify disease severity and to monitor treatment. The one-stage clotting assay (OSA) is used to measure FVIII activity but OSA’s limitations may result in misclassification of disease severity or suboptimal monitoring of treatment. Measurement of FVIII plasma concentration with LC-MS/MS might overcome these challenges.
Objective
To investigate the association between FVIII activity and concentration as well as determinants for discrepancies.
Design and methods
In this cross-sectional study, all haemophilia A patients receiving standard of care were eligible for inclusion. Within the activity categories of < 1%, 1-5%, > 5-40%, > 40-150%, and > 150-600% we randomly selected 15 till 20 plasma samples, and compared FVIII concentration (LC-MS/MS) to FVIII activity (OSA) with linear regression and Bland-Altman analysis. Potential determinants were analysed with linear regression.
Results
87 samples were included. Bland-Altman analysis demonstrated an overall mean difference of –1% with a standard deviation (SD) of 64% between the two methods. Discrepancies were associated with the presence of anti-FVIII antibodies (133%, 95% confidence interval [95%CI] = 81-185, n = 5) and exogenous FVIII products (–37%, 95%CI = –65- –9, n = 58), e.g. plasma-derived and B-domain modified FVIII.
Conclusion
Despite almost no discrepancy overall, the variability between FVIII activity and FVIII concentration was large. Anti-FVIII antibodies or use of exogenous FVIII products might result in differences of potential clinical impact. More research is needed to determine the value of FVIII concentration in addition to activity.