Risks factors for highly unstable response to oral anticoagulation: a case‐control study

Abstract

Summary The factors associated with persistent instability of oral anticoagulant treatment (OAT) were investigated in a case‐control study. The most unstable patients from 35 Italian anticoagulation clinics were matched with stable controls, for gender, age and OAT indication. Socio‐demographic data, medical history, dietary and life habits, cytochrome P450 CYP2C9 variants, blood cell count, liver and renal functions were investigated. An ‘Abbreviated Mental Test’ (AMT) and a questionnaire to assess patient compliance to, and comprehension of, OAT indications and mechanisms were administered. An International Normalized Ratio (INR) above 4·5 was more frequently found in cases (n = 77) than controls (n = 80) (12·3% vs. 0·4%; P < 0·0001). The odds ratio for instability was significantly higher for: people who worked versus pensioners, acenocoumarol versus warfarin, and an insufficient score in the AMT and/or in the questionnaire. Cytochrome P450 CYP2C9 variants *1/*3 or *2/*3 or *3/*3 were more frequent among cases than controls (29·9% vs.15·0%; P = 0·042). No differences were observed as regards the other variables. In conclusion, we found that high intra‐individual variability in OAT control was multifactorial, but poor OAT comprehension was prevalent.

Bleeding Risk in Very Old Patients on Vitamin K Antagonist Treatment

“…It is known that well-informed patients carry a lower risk for adverse events during VKA treatment. 20,25 In Italy, centers devoted to the management of patients on VKA usually perform patient education, including the goals of treatment, the risk of complications, and information on INR values. In addition, family members and caregivers are involved in the education program.…”

Evaluation of Medication Management Safety in Patients Using Oral Anticoagulants

“…The efficiency and accomplishment of the long term OAC treatment depends on the patient taking the treatment seriously and adopting the behaviors essential for the treatment (Ansell, Hirsh, Dalen, Anderson and Deykin 2001;Sharifi, Vajo, Freeman, Bay, Sharifi and Schwartz 2015). In a study performed by Palareti et al (2005), it was expressed that the response to oral anticoagulant treatment may vary and that the biggest variance may stem from the patients' comprehension of the importance of the treatment.…”

EDUC’AVK: Reduction of Oral Anticoagulant-related Adverse Events After Patient Education: A Prospective Multicenter Open Randomized Study

“…However, the risk of therapy with oral anticoagulants is high because deviation from the target therapeutic range is an important cause of treatment failure, due to both recurrence of thromboembolism and hemorrhagic complications [1][2][3][4][5][6] .…”

“…Furthermore, the effects of insufficient understanding of VKA treatment by the patient has already been described 13 . Moreover, insufficient patient education in oral anticoagulation treatment has been related to poorly controlled anticoagulation 2,14 . In particular this deficit has been shown to be the major factor predictive of bleeding in the elderly 15 .…”

“…Notably, VKA allows an 80% risk reduction in the recurrence of thromboembolic events 1,2 . Therefore, according to guidelines, idiopathic or recurrent VTE needs to be indefinitely treated with oral anticoagulant 3 .…”