Atrial Fibrillation (AF), Direct Oral Anticoagulants (DOACs), Medication Adherence
Conditions
Keywords
DOAC;, apixaban, rivaroxaban, dabigatran, edoxaban, dose appropriateness, label-concordant dosing, Proportion of Days Covered (PDC), primary nonadherence, ISTH major bleeding, primary care
Brief summary
SNAP AF-52 is an ambidirectional observational registry conducted in family health centers (primary care) across Ordu, Türkiye, enrolling adults ≥65 years with a pre-existing diagnosis of atrial fibrillation. The study assesses (a) label-concordant dosing of oral anticoagulants (DOACs/warfarin) using drug-specific criteria, and (b) medication adherence via Proportion of Days Covered (PDC) over the prior 12 months (good adherence defined as PDC ≥80%). Unsafe findings (e.g., suspected under-/overdosing, critical drug-drug interactions, very low renal function) trigger same-day referral to tertiary cardiology for evaluation and management. The retrospective window is Dec 1, 2024-Nov 30, 2025; the prospective single-visit inclusion window is Dec 1, 2025-May 31, 2026. No experimental treatment is administered; all care is routine.
Detailed description
Family physicians will screen their ≥65-year attendees with documented AF and record a minimum dataset during a single routine visit: demographics, body weight, most recent serum creatinine (date/value) to compute Cockcroft-Gault creatinine clearance (CrCl), current oral anticoagulant and regimen, common interacting drugs, and pharmacy dispensing dates with days' supply for the last 12 months. The system auto-classifies dose appropriateness per drug label criteria (including apixaban reduction rules; rivaroxaban/dabigatran/edoxaban CrCl thresholds and P-gp/CYP3A4 interactions) and computes PDC with carry-over of early refills; primary nonadherence is defined as no fill within 30 days of the first prescription. Retrospective capture of events includes ischemic stroke/TIA/systemic embolic event (SEE) and hemorrhagic stroke/ISTH major bleeding, plus on-treatment status at the event date. Participants with potentially unsafe dosing or clinically high-risk interaction (e.g., strong inducers; strong dual inhibitors) or CrCl \<15 mL/min are same-day referred to tertiary cardiology. Identifiable data will be stored securely per ethics approval and Turkish data protection (KVKK); only aggregated results will be reported.
Interventions
None listed
Sponsors
Kotyora Family Medicine Health Management and Education Association
Ordu University Faculty of Medicine, Department of Cardiology
Study design
Observational model
COHORT
Time perspective
RETROSPECTIVE
Eligibility
Sex/Gender
ALL
Age
65 Years to No maximum
Healthy volunteers
No
Inclusion criteria
* Age ≥65 years. * Established atrial fibrillation (any type) documented in the medical record. * Presenting to a family health center (primary care) in Ordu province during the prospective window or having records within the retrospective window. * On an oral anticoagulant (DOAC) at any time in the 12-month window.
Exclusion criteria
* Mechanical prosthetic heart valve or moderate-to-severe rheumatic mitral stenosis * Participation in an interventional drug study affecting anticoagulation * Lack of minimal data elements required for dose classification (age, sex, body weight, serum creatinine with date, current OAC and regimen) * Investigator judgment that reliable data cannot be obtained from records
Design outcomes
Primary
| Measure | Time frame | Description |
|---|---|---|
| Primary Outcome 1: Label-Concordant Dose Proportion | At index visit (assessed using baseline variables and the most recent renal function). | Proportion of patients on label-concordant dose vs underdose vs overdose, by anticoagulant. Criteria include: Apixaban: 5 mg BID (standard) or 2.5 mg BID if ≥2 of: age ≥80 years, weight ≤60 kg, serum creatinine ≥1.5 mg/dL. Rivaroxaban: 20 mg QD if CrCl ≥50 mL/min; 15 mg QD if CrCl 15-49; avoid/evaluate if CrCl \<15. Dabigatran: 150 mg BID (standard); 110 mg BID considered if age ≥80 or if CrCl 30-50 and P-gp inhibitor; avoid/evaluate if CrCl \<30. Edoxaban: 60 mg QD (standard); 30 mg QD if CrCl 15-50, weight ≤60 kg, or specific P-gp inhibitors (e.g., dronedarone, verapamil, erythromycin, ketoconazole, cyclosporine); consider reduced efficacy if CrCl \>95. |
| Primary Outcome 2: Good Adherence (PDC ≥80%) | Prior 12 months relative to index date | Proportion of Days Covered (PDC) = (covered days / 365), with early refill carry-over and single-day duplicate fills not double-counted. Good adherence: PDC ≥80% (class-level and drug-specific PDC reported). |
Secondary
| Measure | Time frame | Description |
|---|---|---|
| Secondary Outcome 1: Primary Nonadherence | From first prescription within the 12-month | Yes if no pharmacy dispensing within 30 days of the first OAC prescription. |
| Secondary Outcome 2: Ischemic Events | Prior 12 months. | Proportion with ischemic stroke (ICD-10 I63.x), TIA (G45.x), or systemic arterial embolic event (I74.x); event-date on-treatment status derived from dispensing coverage. |
| Secondary Outcome 3: Hemorrhagic Events | Prior 12 months | Hemorrhagic stroke (I60-I62) and ISTH major bleeding (any of: fatal; critical site-including intracranial/intraspinal/intraocular/pericardial/intra-articular/intramuscular with compartment syndrome; Hb drop ≥2 g/dL; or ≥2 RBC units transfused). Location examples: GI (K92.2; K25-K28 with hemorrhage), GU (R31/N02), pulmonary (R04.2), intra-ocular (H43.1/H35.6). |
| Secondary Outcome 4: Same-Day Tertiary Referral Rate | At index visit | Proportion referred same-day to tertiary cardiology due to unsafe dose, high-risk interaction (e.g., strong inducer/strong dual inhibitor), or CrCl \<15 mL/min. |
Countries
Turkey (Türkiye)
Contacts
PRINCIPAL_INVESTIGATORSeçkin Dereli, MD, Assoc. Prof.
Ordu University Faculty of Medicine, Department of Cardiology (Turkey)
Outcome results
None listed