Prescription of oral anticoagulation after an irregular pulse notification: findings from the apple heart study

Background Patients with atrial fibrillation (AF) are at increased risk for cerebral thromboembolic complications, and oral anticoagulation (OAC) is the standard treatment to mitigate this risk. Management strategies following irregular pulse notifications (IPNs) from wearable devices remain under explored. Purpose We aimed to examine management strategies for OAC therapy following an IPN from a smartwatch in the Apple Heart Study (AHS) that was conducted in the United States. Methods Participants in the AHS that completed the end-of-study (EOS) survey were included. Those who reported pulmonary embolism (PE) were excluded. Participants were grouped according to their IPN status, diagnosis of AF and CHA2DS2-VASc-Score with low risk defined as <1 for men and <2 for women. IPN was recorded on smartwatch devices. Diagnosis of AF or atrial flutter (AFL) and OAC prescription were self-reported in the EOS survey. Results Of the 419,297 participants enrolled in the AHS, 293,678 (70%) completed an EOS survey and did not have a PE. Median age was 39 years, 124,188 (42%) were women and 923 (0.3%) received an IPN (elusive AF). Those who received an IPN were more likely to be prescribed an OAC compared to those without an IPN ([216 (23%) vs. 1,108 (0.4%), standardized mean difference=0.76]). Of the participants who received an IPN, 333 (36%) self-reported AF/AFL and 169 (51%) of these reported an OAC prescription (Table 1). Despite not reporting an AF/AFL diagnosis, OAC prescription was reported by 47 (8%) participants who received IPNs, without any strokes or TIAs. Among the 362 participants receiving IPN with a low CHA₂DS₂-VASc-Score, 41 (11%) participants reported OAC use, compared with the non-IPN cohort (386 [(0.2%), SMD=0.49]) (Table 1). Despite, OAC being frequently prescribed in participants of female sex, with at least one comorbidity, or >65 years, the effect of receiving an IPN on OAC prescription was more pronounced in participants <65 years old, with low CHA2DS2-VASc-Score or without co-morbidities compared with the ones with a high CHA2DS2-VASc-Score or the ones reporting concomitant risk factors (Figure 1). Conclusions Among AHS participants who received an IPN 23% were prescribed an OAC, with apixaban being the most frequently prescribed DOAC. Notably, 8% of individuals who received an IPN without reporting prior diagnosis of AF were prescribed an OAC, suggesting potentially enhanced medical management in this cohort. Although, OAC prescription following IPN receipt was more frequent among females, elderly participants and those of elderly age, participants with low stroke risk reported OAC prescription rates of 11%. These findings highlight the need for further investigation into stroke risk stratification and optimal medical therapeutic strategies for patients with elusive AF.