Semantic computational analysis of anticoagulation use in atrial fibrillation from real world data

Atrial fibrillation (AF) is the most common arrhythmia and significantly increases stroke risk. This risk is effectively managed by oral anticoagulation. Recent studies using national registry data indicate increased use of anticoagulation resulting from changes in guidelines and the availability of newer drugs. The aim of this study is to develop and validate an open source risk scoring pipeline for free-text electronic health record data using natural language processing. AF patients discharged from 1st January 2011 to 1st October 2017 were identified from discharge summaries (N = 10,030, 64.6% male, average age 75.3 ± 12.3 years). A natural language processing pipeline was developed to identify risk factors in clinical text and calculate risk for ischaemic stroke (CHA2DS2-VASc) and bleeding (HAS-BLED). Scores were validated vs two independent experts for 40 patients. Automatic risk scores were in strong agreement with the two independent experts for CHA2DS2-VASc (average kappa 0.78 vs experts, compared to 0.85 between experts). Agreement was lower for HAS-BLED (average kappa 0.54 vs experts, compared to 0.74 between experts). In high-risk patients (CHA2DS2-VASc ≥2) OAC use has increased significantly over the last 7 years, driven by the availability of DOACs and the transitioning of patients from AP medication alone to OAC. Factors independently associated with OAC use included components of the CHA2DS2-VASc and HAS-BLED scores as well as discharging specialty and frailty. OAC use was highest in patients discharged under cardiology (69%). Electronic health record text can be used for automatic calculation of clinical risk scores at scale. Open source tools are available today for this task but require further validation. Analysis of routinely collected EHR data can replicate findings from large-scale curated registries.info:eu-repo/semantics/publishedVersio

Time trends in atrial fibrillation-associated stroke and premorbid anticoagulation

Background and Purpose Prevalence of atrial fibrillation (AF) is increasing, but the impact on overall burden of stroke is uncertain, as is the proportion that could be attributed to under anticoagulation. We did a population-based study of AF-associated stroke and a systematic review of time trends in other stroke incidence studies and of rates of premorbid anticoagulation. Methods The proportion of incident strokes with associated AF was determined in the OXVASC (Oxford Vascular Study; 2002–2017) and in other prospective, population-based stroke incidence studies published before December 2017. Proportions were pooled by Mantel Haenszel methods, and the pooled percentage of cases with premorbid anticoagulation was determined. Analyses were stratified by the age of study population, mid-study year, country, and ethnicity. Results Of 1928 patients with incident ischemic stroke in OXVASC, 629 (32.6%; 95% CI, 30.5–34.7) were AF associated, consistent with the pooled estimate from 4 smaller studies over the same study period (608/1948; 31.2%, 30.0–32.4; Phet=0.80). The pooled estimate from all studies reporting premorbid AF over 25 million person-years of observation (1960 onwards; 33 reports) was lower (18.6%, 16.8–20.3) and more heterogeneous (Phet&lt;0.0001), but 62% of heterogeneity was explained by the age of study population, study period, country, and ethnicity. The proportion of incident strokes on premorbid anticoagulation increased over time, both for ischemic stroke in OXVASC (2002–2007: 15.1%, 2008–2012: 19.6%, and 2013–2017: 35.9%; Ptrend&lt;0.0001), and across all studies (P=0.002), but the pooled estimates suggested substantial undertreatment even in the most recent periods (2001–2015: 25.7%, 21.1–30.3 and ≥2010: 31.6%, 18.2–44.9). Conclusions About 1 in 3 incident ischemic strokes are still AF associated, due partly to low rates of anticoagulation for known prior AF, which therefore represents a major public health opportunity to reduce the burden of stroke.</p