There is currently no consensus on whether atrial fibrillation (AF) patients at low risk for stroke (one non-sex-related CHA₂DS₂-VASc point) should be treated with an oral anticoagulant. We conducted a multi-country cohort study in Sweden, Denmark, Norway, and Scotland. In total, 59 076 patients diagnosed with AF at low stroke risk were included. We assessed the rates of stroke or major bleeding during treatment with a non-vitamin K antagonist oral anticoagulant (NOAC), a vitamin K antagonist (VKA), or no treatment, using inverse probability of treatment weighted (IPTW) Cox regression. In untreated patients, the rate for ischaemic stroke was 0.70 per 100 person-years and the rate for a bleed was also 0.70 per 100 person-years. Comparing NOAC with no treatment, the stroke rate was lower [hazard ratio (HR) 0.72; 95% confidence interval (CI) 0.56–0.94], and the rate for intracranial haemorrhage (ICH) was not increased (HR 0.84; 95% CI 0.54–1.30). Comparing VKA with no treatment, the rate for stroke tended to be lower (HR 0.81; 95% CI 0.59–1.09), and the rate for ICH tended to be higher during VKA treatment (HR 1.37; 95% CI 0.88–2.14). Comparing NOAC with VKA treatment, the rate for stroke was similar (HR 0.92; 95% CI 0.70–1.22), but the rate for ICH was lower during NOAC treatment (HR 0.63; 95% CI 0.42–0.94). These observational data suggest that NOAC treatment may be associated with a positive net clinical benefit compared with no treatment or VKA treatment in patients at low stroke risk, a question that can be tested through a randomized controlled trial. In patients with atrial fibrillation at low stroke-risk from Sweden, Denmark, Scotland, and Norway, treatment with a NOAC was associated with a lower stroke rate compared to no treatment and a lower intracranial haemorrhage rate compared to VKA treatment. NOAC, non-vitamin K antagonist oral anticoagulant; VKA, vitamin K antagonist; HR, hazard ratio; VS, versus.

Aims: The aim of this study was to compare the clinical effectiveness and safety of direct oral anticoagulants (DOACs) in patients with atrial fibrillation (AF) in routine clinical practice.Methods: This retrospective cohort study used linked administrative data. The study population (n = 14 577) included patients with a diagnosis of AF (confirmed in hospital) who initiated DOAC treatment in Scotland between August 2011 and December 2015. Multivariate Cox proportional hazard models were used to estimate hazard ratios of thromboembolic events, mortality and bleeding events.Results: No differences between the DOACs were observed with regard to the risk of stroke, systemic embolism or cardiovascular death. In contrast, the risk of myocardial infarction was higher among patients prescribed apixaban in comparison to those on rivaroxaban (HR 1.67, 95% CI 1.02‐2.71), and all‐cause mortality was higher among rivaroxaban patients in contrast to both apixaban (1.22 [1.01–1.47]) and dabigatran (1.55 [1.16–2.05]) patients; rivaroxaban patients also had a higher risk of pulmonary embolism than apixaban patients (5.27 [1.79–15.53]). The risk of other major bleeds was higher among rivaroxaban patients compared to apixaban (1.50 [1.10–2.03]) and dabigatran (1.58 [1.01–2.48]) patients; the risks of gastrointestinal bleeds and overall bleeding were higher among rivaroxaban patients than among apixaban patients (1.48 [1.01–2.16] and 1.52 [1.21–1.92], respectively).Conclusions: All DOACs were similarly effective in preventing strokes and systemic embolisms, while patients being treated with rivaroxaban exhibited the highest bleeding risks. Observed differences in the risks of all‐cause mortality, myocardial infarction and pulmonary embolism warrant further research.

Purpose: To report the use of direct oral anticoagulants (DOACs) for stroke prevention in patients with atrial fibrillation in Scotland and advocate the standardisation of drug utilisation research methods.Methods: Retrospective cohort study using linked administrative data. Patients included those with a diagnosis of atrial fibrillation (confirmed in hospital) who received a first prescription for a DOAC (dabigatran, rivaroxaban, or apixaban) from September 2011 to June 2014. Drug utilisation measures included discontinuation, persistence, and adherence.Results: A total of 5398 patients (mean CHA₂DS₂‐VASc score 2.98 [SD 1.71], 89.7% with ≥5 concomitant medicines) were treated with DOACs for a median of 228 days (interquartile range 105‐425). Of 35.6% who discontinued DOAC treatment, 11.0% switched to warfarin, and 48.3% reinitiated DOACs. Persistence after 12 and 18 months was 75.9% and 69.8%, respectively. Differences between individual DOACs were observed: Discontinuation rates ranged from 20.4% (apixaban) to 60.6% (dabigatran) and 12 months persistence from 60.1% (dabigatran) to 85.5% (apixaban). Adherence to treatment with all DOACs was good: Overall DOAC median medication refill adherence was 102.9% (interquartile range 88.9%‐115.5%), and 82.3% of patients had a medication refill adherence > 80%.Conclusions: In Scotland, adherence to DOAC treatment was good, and switching from DOAC to warfarin was low. However, discontinuation and persistence rates were variable—although treatment interruptions were often temporary.To decrease the inconsistencies in drug utilisation methods and facilitate meaningful study comparison, the use of a coherent framework—using a combination of discontinuation, persistence, and adherence—and the standardisation of measurements is advocated.

Aim: To assess associations between statin intensity and adherence, persistence and discontinuation of statin therapy in Scotland.Method: Retrospective cohort study, using linked electronic health records covering a period from January 2009 to December 2016. The study cohort included adult patients (≥18 years) newly initiating statins within Greater Glasgow and Clyde, Scotland. Study outcomes comprised adherence, discontinuation and persistence to treatment, stratified by three exposure groups (high, moderate and low intensity). Discontinuation and persistence were calculated using the refill‐gap and anniversary methods, respectively. Proportion of days covered (PDC) was used as a proxy for adherence. Kaplan‐Meier survival curves and Cox proportional hazard models were used to evaluate discontinuation, and associations between adherence/persistence and statin intensity were assessed using logistic regression.Results: A total of 73 716 patients with a mean age of 61.4 ± 12.6 years were included; the majority (88.3%) received moderate intensity statins. Discontinuation rates differed between intensity levels, with high‐intensity patients less likely to discontinue treatment compared to those on moderate intensity (prior cardiovascular disease [CVD]: HR 0.43 [95% CI 0.34‐0.55]; no prior CVD: 0.80 [0.74‐0.86]). Persistence declined over time, and high‐intensity patients had the highest persistence rates. Overall, 52.6% of patients were adherent to treatment (PDC ≥ 80%), but adherence was considerably higher among high‐intensity patients (63.7%).Conclusion: High‐intensity statins were associated with better persistence and adherence to treatment, but overall long‐term persistence and adherence remain a challenge, particularly among patients without prior CVD. This needs addressing.