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Enrolling by Invitation

NCT Number: NCT07242326

SNAP AF-52: Dose Appropriateness and Adherence to Oral Anticoagulation in Adults ≥65 With Atrial Fibrillation in Primary Care (Ordu, Türkiye)

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.

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Key information

Conditions

Medication Adherence Arrhythmias, Cardiac Atrial Fibrillation Atrial Fibrillation (AF) Behavior Cardiovascular Diseases Direct Oral Anticoagulants (DOACs) Health Behavior Heart Diseases Pathologic Processes Pathological Conditions, Signs and Symptoms Patient Acceptance of Health Care Patient Compliance Treatment Adherence and Compliance

Age range

65 year and older

Sex eligibility

All sexes

Study type

Observational

Primary location

Ordu University Faculty of Medicine, Department of Cardiology

Ordu, 52200, Turkey (Türkiye)

About this study

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.

Who can participate

Healthy volunteers accepted: No

Only the study team can determine whether someone qualifies for participation.

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

Treatment and study plan

Primary outcomes

  1. Primary Outcome 1: Label-Concordant Dose Proportion

    Time frame: 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.

  2. Primary Outcome 2: Good Adherence (PDC ≥80%)

    Time frame: 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 outcomes

  1. Secondary Outcome 1: Primary Nonadherence

    Time frame: From first prescription within the 12-month

    Yes if no pharmacy dispensing within 30 days of the first OAC prescription.

  2. Secondary Outcome 2: Ischemic Events

    Time frame: 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.

  3. Secondary Outcome 3: Hemorrhagic Events

    Time frame: 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).

  4. Secondary Outcome 4: Same-Day Tertiary Referral Rate

    Time frame: 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.

Sponsors and collaborators

Lead sponsor

Kotyora Family Medicine Health Management and Education Association

Network

Collaborators

  • Ordu University Faculty of Medicine, Department of Cardiology

Registry information

Official study title

SNAP AF-52 - An Ambidirectional Observational Study to Assess Label-Concordant Dosing and Medication Adherence (Proportion of Days Covered) for Oral Anticoagulants in Adults Aged ≥65 Years With Atrial Fibrillation Managed in Family Health Centers in Ordu, Türkiye, With Same-Day Tertiary Cardiology Referral for Unsafe Findings

Acronym: SNAP AF-52

Important dates

Study start
2025
Primary completion
2026
Study completion
2026
First posted
Nov 21, 2025
Registry last updated
Feb 25, 2026

OpenTrials presents study information sourced from ClinicalTrials.gov. The official registry record should be consulted for the latest information.

View the official ClinicalTrials.gov record (opens in a new tab)

This listing is for discovery and informational purposes only. It is not medical advice, does not guarantee that a study is recruiting, and does not determine eligibility. Contact the study team and a qualified healthcare professional when considering participation.

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