Characteristics of included studies
| Study | Cohort (country) | Study aim | EHR description | AF cases (n)/total patients (n) (%) | Age (mean±SD) | Female (%) | BMI (mean±SD) | Diabetes (%) | Hypertension (%) | Heart failure (%) | Outcome definition | Outcome coding | Enrolment period (mean F/U in years) | Exclusion criteria |
| Aronson et al 26 | MHS (IL) | D | Ambulatory clinics | 5660/96 778 (5.80) | 62.0 ±9.0 | 53.7 | 28.2 ±5.1 | 13.5 | 34.3 | 1.00 | AF, AFI | ICD codes | 2005–2015 (10.0) | Past history of AF, incomplete follow-up |
| Chao et al 27 | NHIRD (TW) | EV | National health insurance | 9187/702 502 (1.30) | 41.3 ±16.4 | 49.1 | N/A | 3.1 | 5.2 | 0.40 | AF* | ICD codes* | 2000–2009 (9.0) | Age <18 years, past history of cardiac arrhythmia, rheumatic heart disease |
| Hill et al 28 | CPRD (UK) | D, EV | Nationwide primary care | 95 607/2994 837 (3.19) | 56.0 ±14.5 | 53.4 | 27.6 ±6.0 | 6.9 | 25.0 | 0.70 | AF, AFI | Read codes | 2006–2016 (N/A) | Age <30 years, past history of AF |
| Himmelreich et al 9 | Nivel-PCD (NL) | EV | Nationwide primary care | 5264/111 475 (4.72) | 65.5 ±11.4 | 52.5 | N/A | 42.7 | 66.5 | 4.20 | AF, AFl | ICPC-1 codes | 2013–2018 (N/A) | Age <40 years, past history of AF |
| Hu W-S et al†29 | NHIRD (TW) | D | National health insurance | 14 212/682 237 (2.08) | 41.3 | 49.3 | N/A | 2.1 | 15.1 | 0.80 | AF | ICD codes | 2000–2013 (7.1) | Age <18 years, past history of AF, incomplete data |
| Hu W-S and Lin C-L30 | NHIRD (TW) | EV | National health insurance | 12 051/692 691 (1.74) | 41.3 ±16.3 | 49.4 | N/A | N/A | 14.4 | 0.49 | AF | ICD codes | 1996–2013 (10.9) | Age <18 years, past history of AF, incomplete data |
| Kim et al†35 | NHIS-NSC (KR) | D, EV | National Health Insurance | 5824/432 587 (1.35) | 47.7 | 50.5 | 23.7 | 6.3 | 21.2 | 2.40 | AF, AFl | ICD codes | 2009–2013 (N/A) | Age <18 years, past history of AF, mitral valve stenosis or prosthetic valve disease, missing data for smoking or alcohol, change in residence |
| Li et al†31 | YMID (CN) | D, EV | Regional medical insurance | 921/471 446 (0.20) | 47.0 | 47.3 | N/A | 4.0 | 9.7 | 0.15 | AF | ICD codes | 2001–2012 (4.1) | Past history of AF, incomplete data, readmission |
| NHIS-HEALS (KR) | EV | National health examination programme | 12 143/451 199 (2.69) | 56.1 ±9.3 | 46.0 | N/A | 8.3 | 31.7 | 1.20 | AF | ICD codes | 2002–2013 (7.3) | Past history of AF, mitral stenosis, prosthetic heart valves, valve replacement or valvuloplasty or cardiomyopathy | |
| Saliba et al 32 | ClalitHS (IL) | EV | State-mandated health services | 23 223/1062 073 (2.19) | 65.7 ±11.2 | 54.7 | N/A | 25.3 | 48.9 | 4.30 | AF | ICD codes | 2012–2014 (2.9) | Age <50 years, past history of AF |
| Sekelj et al 33 | Discover (UK) | EV | Regional primary care | 17 880/604 135 (2.96) | 52.2 ±13.3 | 51.0 | 27.0 ±6.1 | 23.2 | 17.9 | 0.50 | AF, AFl | Read codes | 2006–2013 (N/A) | Age <30 years, past history of AF, incomplete data for height, weight, BMI, systolic BP and diastolic BP |
| Suenari et al 34 | NHIRD (TW) | EV | National health insurance | 9174/670 804 (1.40) | 42.4 ±16.0 | 49.1 | N/A | 3.2 | 5.5 | 0.40 | AF | ICD codes | 2000–2011 (9.0) | Age <20 years, past history of cardiac arrhythmia |
*In Chao it is not reported how outcome was defined or measured but given the authors were using the same database as Suenari, we have assumed outcomes were measured in the same way.
†In Kim, Li and Hu W-S the percentage of patients related to sex, diabetes, hypertension, heart failure was calculated from reported values categorised by incident AF or not.
AF, atrial fibrillation; AFl, atrial flutter; BMI, body mass index; BP, blood pressure; ClalitHS, Clalit Health Services; CN, China; CPRD, Clinical Practice Research Datalink; D, derivation; EHR, electronic health records; EV, external validation; F/U, follow-up; ICD, International Classification of Diseases; ICPC-1, International classification of Primary care version 1 diagnostic codes; IL, Israel; KR, Republic of Korea; MHS, Maccabi Healthcare Services; N/A, not available; NHIRD, National Health Insurance Research Database; NHIS-HEALS, National Health Insurance Service - Health screening Cohort; NHIS-NSC, National Health Insurance Service-based National Sample Cohort; Nivel-PCD, Netherlands Institute for Health Services Research Primary Care Database; NL, Netherlands; TW, Taiwan; YMID, Yunnan Medical Insurance Database.