Association between Renal Function and Bleeding Risk for Dabigatran after Switching from Warfarin.

Area of Science:

• Pharmacology
• Nephrology
• Cardiology

Background:

• Dabigatran use is associated with a higher risk of gastrointestinal (GI) bleeding compared to warfarin.
• The impact of renal function on this bleeding risk during dabigatran conversion is not fully understood.

Purpose of the Study:

• To analyze the effect of renal function on the relative risk of GI bleeding in patients switching from warfarin to dabigatran.
• To compare bleeding event rates between patients converted to dabigatran and those remaining on warfarin, stratified by renal function.

Main Methods:

• A retrospective study of elderly patients (≥65 years) on warfarin for ≥6 months, comparing those converted to dabigatran (150 mg twice daily) with those who continued warfarin.
• Propensity score matching was used to create comparable groups.
• Outcomes included hospital admissions for GI or major bleeding and mortality, stratified by estimated glomerular filtration rate (eGFR).

Main Results:

• The study included 864 patients converted to dabigatran and 1,710 who remained on warfarin.
• In patients with eGFR 50-80 ml/min/1.73 m², dabigatran initiation was associated with a nearly 3-fold higher hazard of GI bleeding (4.1 vs. 1.3 per 100 patient-years; HR 2.94; p = 0.015) compared to warfarin.
• Bleeding events outside the GI tract and in patients with eGFR <50 or >80 ml/min/1.73 m² were infrequent.

Conclusions:

• Healthcare providers should exercise caution and monitor closely for bleeding when converting patients from warfarin to dabigatran.
• This caution is advised even for patients with renal function within the currently recommended safe range for dabigatran.