Association of and single-nucleotide polymorphisms with warfarin dose adjustment in Saudi patients.

Objectives: Despite its wide usage, warfarin therapy remains challenging due to its narrow therapeutic index, inter-individual response variability, and risk of bleeding. Previous reports have suggested that polymorphisms in and genes could influence warfarin therapy. Herein, we investigated whether  -1173C>T, , and gene polymorphisms are associated with warfarin dose adjustment and related bleeding events.

Methods: This cross-sectional study was conducted on Saudi adults receiving warfarin for more than 1 month. Their demographics and relevant clinical data were obtained. Genotyping for  -1173C>T, , and genotypes was performed.

Results: Patients who are homozygous for the mutant T allele T/T required the lowest warfarin daily maintenance dose, compared to C/T and C/C. Similarly, there was a significant reduction in warfarin daily maintenance dose among and groups compared to . However, we found no significant correlation between the studied polymorphisms and warfarin-associated bleeding.

Conclusions: Similar to other populations, the and gene polymorphisms are significantly associated with warfarin dosage in Saudi patients. The presence of at least one copy of the mutant alleles for  -1173C>T, , and is associated with a significant reduction in warfarin maintenance dose.