What is the clinical evidence from this study?

Study design: Cohort. Population: Valvular heart disease (n=4872). Intervention: Direct oral anticoagulants (DOACs) vs. Warfarin. Primary outcome: Nonadherence to anticoagulation therapy (PDC < 80%) (OR 1.51, 95% CI 1.08-2.11).

What question did this study set out to answer?

This study aims to evaluate anticoagulant adherence and associated clinical outcomes in older adults after valve replacement surgery.

April 12, 2026Open Access

Anticoagulant adherence and associated complications and readmissions in older valve surgery adults: insights from a retrospective cohort study

Q: What are the key findings of this study?

Direct oral anticoagulant users had a higher likelihood of nonadherence compared to warfarin users (OR 1.51) but exhibited lower observed 1-year mortality rates (4.31% vs. 8.36%).

Q: What question did this study set out to answer?

This study aims to evaluate anticoagulant adherence and associated clinical outcomes in older adults after valve replacement surgery.

Key Result

Direct oral anticoagulant users had a higher likelihood of nonadherence compared to warfarin users (OR 1.51) but exhibited lower observed 1-year mortality rates (4.31% vs. 8.36%).

Key Points

This study aims to evaluate anticoagulant adherence and associated clinical outcomes in older adults after valve replacement surgery.
Analysis of Taiwan National Health Insurance Research Database.
Inclusion of 4,872 patients aged ≥ 65 years with valvular heart disease following valve replacement.
Data collection on anticoagulant use and adherence defined as ≥ 80% coverage over 180 days post-discharge.
Application of multivariable logistic regression and Cox proportional hazards models for outcome evaluation.
38.53% of patients did not receive any oral anticoagulant after discharge.
Higher adherence rates observed among warfarin users compared to DOAC users.
Nonadherence more prevalent among DOAC users, linked to higher stroke-related readmissions.
DOAC users had lower 1-year mortality rates compared to warfarin users (4.31% vs. 8.36%).

Study Design

Type

Cohort (n=4,872)

Multicenter

Yes

Structured PICO

Does the use of DOACs compared to warfarin affect medication adherence, mortality, and readmissions in older adults following valve replacement surgery?

Population

4,872 patients aged ≥ 65 years with valvular heart disease who underwent valve replacement between 2010 and 2020. Excluded: history of end-stage renal disease, venous thromboembolism, or ischemic stroke before the index surgery.

Intervention

Direct oral anticoagulants (DOACs) prescribed after discharge

Comparator

Warfarin prescribed after discharge

Outcome

Anticoagulant adherence (defined as prescriptions covering ≥ 80% of days during a fixed 180-day post-discharge window) and clinical outcomes including mortality and readmissionshard clinical

In older adults following valve replacement surgery, DOAC use was associated with lower medication adherence but lower 1-year mortality compared to warfarin, though the observational design limits causal inference.

Main Result

Effect estimate: OR 1.51 (95% CI 1.08-2.11)

Limitations

Treatment allocation was not randomized, making it difficult to establish causal relationships.
The database did not reliably distinguish valve type (mechanical vs bioprosthetic) or postoperative indications for long-term anticoagulation.
Laboratory parameters, including renal function indices and INR values, were not available in the database.

Abstract

Valvular heart disease frequently affects older adults and necessitates valve replacement surgery followed by anticoagulation therapy. Although direct oral anticoagulants (DOACs) are increasingly used for atrial fibrillation and venous thromboembolism, they are not approved for use in mechanical heart valves. This study evaluated anticoagulant adherence and clinical outcomes among older patients after valve replacement using Taiwan’s National Health Insurance data. This retrospective cohort study used the Taiwan National Health Insurance Research Database and included 4,872 patients aged ≥ 65 years with valvular heart disease who underwent valve replacement between 2010 and 2020. Patients with a history of end-stage renal disease, venous thromboembolism, or ischemic stroke before the index surgery were excluded. Anticoagulant use after discharge was identified, and medication adherence was defined as prescriptions covering ≥ 80% of days during a fixed 180-day post-discharge window. Multivariable logistic regression and Cox proportional hazards models were used to evaluate factors associated with adherence and clinical outcomes, including mortality and readmissions. Among the included patients, 38.53% did not receive any oral anticoagulant after discharge. Warfarin users demonstrated higher adherence rates than DOAC users. Females and those aged ≥ 75 years showed better adherence. Nonadherence was more common among DOAC users (OR: 1.51; 95% CI: 1.08–2.11) and was associated with higher stroke-related readmissions (DOACs, 7.63%; warfarin, 6.20%), although causal relationships cannot be established. DOAC users had lower observed 1-year mortality rates (4.31% vs. 8.36%) and similar rates of major bleeding events (6.12% vs. 6.34%) compared with warfarin users. Differences in anticoagulant adherence and clinical outcomes were observed among older patients following valve surgery. Warfarin users showed higher measured adherence, whereas DOAC users had lower observed mortality. Because treatment allocation was not randomized and adherence is closely related to treatment type, the independent effect of adherence on outcomes cannot be completely established. Therefore, these findings should be interpreted cautiously prospective studies should be conducted to elucidate the relationship between adherence and clinical outcomes.

Bookmark

View Full Paper