ObjectivesTo examine the characteristics and persistence in patients newly initiated with oral anticoagulants (OACs) for stroke prevention in non-valvular atrial fibrillation (NVAF).DesignCohort study in Clinical Practice Research Datalink.SettingUK primary care.Participants15 242 patients with NVAF newly prescribed apixaban, rivaroxaban, dabigatran or vitamin K antagonists (VKAs) between 1 December 2012 and 31 October 2014. 13 089 patients were OAC naïve.Outcome measuresPatient characteristics and risk of non-persistence compared to apixaban using Cox regression models over the entire follow-up and using a time-partitioned approach to handle non-proportional hazards.ResultsAmong the OAC naïve patients, VKAs were most common (78.1%, n=10 218), followed by rivaroxaban (12.1%, n=1589), dabigatran (5.7%, n=741) and apixaban (4.1%, n=541). High baseline stroke risk (CHA2DS2VASc ≥2) ranged from 80.2% (dabigatran) to 88.4% (apixaban and rivaroxaban). History of stroke and bleeding was the highest among apixaban (23.7% and 31.6%) and lowest among VKA patients (15.9% and 27.5%). Across the entire follow-up period, adjusting for differences in characteristics, there was no evidence of a difference in non-persistence between VKA and apixaban (HR 0.92 (95% CI 0.68 to 1.23)). Non-persistence was higher with dabigatran (HR 1.67 (1.20 to 2.32)) and rivaroxaban (HR 1.41 (1.02 to 1.93)) than apixaban. Using the partitioned approach, non-persistence was lower with VKA (HR 0.33 (0.22 to 0.48)), and higher with dabigatran (HR 1.65 (1.08 to 2.52)) compared to apixaban in the first 2 months of follow-up. After 2 months, non-persistence was higher with VKA (HR 1.70 (1.08 to 2.66)) and dabigatran (HR 2.10 (1.30 to 3.41)). Pooling OAC naïve and experienced patients, non-persistence was also higher with rivaroxaban compared to apixaban after 2 months of follow-up (HR 1.69 (1.19 to 2.39)).ConclusionsObserved differential prescribing of OACs can result in channelling bias in comparative effectiveness research. Persistence patterns changed over follow-up time, but there are indications of improved persistence rates with apixaban over other OACs in the UK. A larger study with longer follow-up is needed to corroborate findings. This study is registered on ClinicalTrials.gov (NCT02488421).

This study examined characteristics and treatment persistence among patients prescribed oral anticoagulants (OACs) for stroke prevention in non-valvular atrial fibrillation (NVAF). We identified 15,244 patients (51.8% male, 72.7% aged ≥70) with NVAF and no prior OAC therapy who were prescribed apixaban (n = 1,303), rivaroxaban (n = 5,742), dabigatran (n = 1,622) or vitamin-K antagonists (VKAs, n = 6,577) between 1-Dec-2012 and 31-Oct-2014 in German primary care (IMS® Disease Analyzer). We compared OAC persistence using Cox regression over patients’ entire follow-up and using a data-driven time-partitioned approach (before/after 100 days) to handle non-proportional hazards. History of stroke risk factors (stroke/transient ischaemic attack [TIA] 15.2%; thromboembolism 14.1%; hypertension 84.3%) and high bleeding risk (HAS-BLED score≥3 68.4%) was common. Apixaban-prescribed patients had more frequent history of stroke/TIA (19.7%) and high bleeding risk (72.6%) than other OACs. 12-month persistence rates were: VKA 57.5% (95% confidence interval (CI) 56.0–59.0%), rivaroxaban 56.6% (54.9–58.2%), dabigatran 50.1% (47.2–53.1%), apixaban 62.9% (58.8–67.0%). Over entire follow-up, compared to VKA, non-persistence was similar with apixaban (adjusted hazard ratio 1.08, 95% CI 0.95–1.24) but higher with rivaroxaban (1.21, 1.14–1.29) and dabigatran (1.53, 1.40–1.68). Using post-hoc time-partitioned approach: in first 100 days, non-persistence was higher with apixaban (1.37, 1.17–1.59), rivaroxaban (1.41, 1.30–1.53) and dabigatran (1.91, 1.70–2.14) compared to VKA. Compared to apixaban, rivaroxaban non-persistence was similar (1.03, 0.89–1.20), dabigatran was higher (1.39, 1.17–1.66). After 100 days, apixaban non-persistence was lower than VKA (0.66, 0.52–0.85); rivaroxaban (0.97, 0.87–1.07) and dabigatran (1.10, 0.95–1.28) were similar to VKA. Furthermore, rivaroxaban (1.46, 1.13–1.88) and dabigatran (1.67, 1.26–2.19) non-persistence was higher than apixaban. This study describes real-world observations on OAC use, particularly early apixaban use following approval for NVAF, in Germany. We identified potential differential OAC prescribing and higher persistence with apixaban than other OACs after 100 days’ treatment. Larger studies are needed with longer follow-up to establish long-term patterns.

ObjectiveThe aim of this study was to examine the prevalence of major congenital malformations associated with antiepileptic drug (AED) treatment in pregnancy.Patients and methodsUsing data from The Health Improvement Network, we identified women who have given live birth and their offspring. Four subgroups were selected based on the AED treatment in early pregnancy, valproate, carbamazepine, lamotrigine and women not receiving AED treatment. We compared the prevalence of major congenital malformations within children of these four groups and estimated prevalence ratios (PRs) using Poisson regression adjusted for maternal age, sex of child, quintiles of Townsend deprivation score and indication for treatment.ResultsIn total, 240,071 women were included in the study. A total of 229 women were prescribed valproate in pregnancy, 357 were prescribed lamotrigine and 334 were prescribed carbamazepine and 239,151 women were not prescribed AEDs. Fifteen out of 229 (6.6%) women prescribed valproate gave birth to a child with a major congenital malformation. The figures for lamotrigine, carbamazepine and women not prescribed AEDs were 2.7%, 3.3% and 2.2%, respectively. The prevalence of major congenital malformation was similar for women prescribed lamotrigine or carbamazepine compared to women with no AED treatment in pregnancy. For women prescribed valproate in polytherapy, the prevalence was fourfold higher. After adjustments, the effect of estimates attenuated, but the prevalence remained two- to threefold higher in women prescribed valproate.ConclusionThe results of our study suggest that lamotrigine and carbamazepine are safer treatment options than valproate in pregnancy and should be considered as alternative treatment options for women of childbearing potential and in pregnancy.

Non-persistence (treatment discontinuation or switch) with vitamin K antagonists was lower than with rivaroxaban and dabigatran in French primary care; however, non-persistence with the newest drug, apixaban, was similar to vitamin K antagonists. Larger studies with longer follow-up are needed to support these findings. This study is registered on ClinicalTrials.gov (NCT02488421).

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