Summary
The aims of this case-control study were to identify in vitamin K antagonist (VKA)-treated
unselected patients, factors associated with international normalised ratio (INR)
values: (i) greater than 6.0.;and (ii) ranging from 4.0 to 6.0 complicated with bleeding.
We also assessed VKA-related morbidity in these patients. During a two-month period,
4,188 consecutive and unselected patients were referred to our Emergency Department.
At admission, the medical records of each patient and two age- and sex-matched controls
were reviewed for: both duration and indication of VKA therapy, previous medical history
of VKA-related haemorrhage, underlying co-morbidities, concomitant medications other
than VKA, duration of hospitalization and deaths’ causes. Of these 4,188 subjects,50
case-patients (1.19%) were identified; both case-patients and controls did not differ
as regards indications and patterns of VKA therapy. Interestingly, two-thirds of case-patients
were women, suggesting that female gender may be a risk factor of VKA over-coagulation
onset. We identified the following risk factors of VKA over-coagulation: previous
medical history of INR levels over therapeutic range, therapy with antibiotics, amiodarone
and proton pump inhibitors, as well as fever. A total of 88% of case-patients were
hospitalized; mean duration of patients’ hospitalization was seven days [range:1–56
days];no patient died from major bleeding. Our study underscores that it is of utmost
importance to consider the strength of indication before starting VKA therapy, as
this therapy has been responsible for as high as 1.19% of admissions in unselected
subjects referred to an Emergency Department. Our data therefore suggest that internists
should be aware of VKA-related high morbidity, particularly in situations at risk
of VKA over-coagulation.
Keywords
Vitamin K antagonist - haemorrhage - risk factors - proton pump inhibitors - gender
- outcome - morbidity - mortality
