title: Risks factors for highly unstable response to oral anticoagulation: a case-control study.
abstract: 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.
authors.affiliation: Dipartimento di Angiologia e Malattie della Coagulazione 'Marino Golinelli', Policlinico S. Orsola-Malpighi, Università di Bologna, Bologna, Italy. palareti@tin.it
authors.forename: Gualtiero
authors.initials: G
authors.lastname: Palareti
authors.forename: Cristina
authors.initials: C
authors.lastname: Legnani
authors.forename: Giuliana
authors.initials: G
authors.lastname: Guazzaloca
authors.forename: Valdré
authors.initials: V
authors.lastname: Lelia
authors.forename: Benilde
authors.initials: B
authors.lastname: Cosmi
authors.forename: Barbara
authors.initials: B
authors.lastname: Lunghi
authors.forename: Giovanna
authors.initials: G
authors.lastname: Marchetti
authors.forename: Daniela
authors.initials: D
authors.lastname: Poli
authors.forename: Vittorio
authors.initials: V
authors.lastname: Pengo
mesh_terms: D000074:Acenocoumarol / Q000008:administration & dosage; D000328:Adult; D000368:Aged; D000925:Anticoagulants / Q000008:administration & dosage*; D001189:Aryl Hydrocarbon Hydroxylases / Q000235:genetics; D001777:Blood Coagulation / Q000187:drug effects / Q000235:genetics; D016022:Case-Control Studies; D065729:Cytochrome P-450 CYP2C9; D004334:Drug Administration Schedule; D005260:Female; D007722:Health Knowledge, Attitudes, Practice; D006801:Humans; D019934:International Normalized Ratio; D008297:Male; D008875:Middle Aged; D010349:Patient Compliance; D010353:Patient Education as Topic; D011594:Psychometrics; D012307:Risk Factors; D012646:Self Administration / Q000523:psychology; D014859:Warfarin
chemical_list: D000925:Anticoagulants; D014859:Warfarin; C450260:CYP2C9 protein, human; D065729:Cytochrome P-450 CYP2C9; D001189:Aryl Hydrocarbon Hydroxylases; D000074:Acenocoumarol