Data collection and follow-up

Upon enrollment, patients were interviewed using a standardized questionnaire, and their records were reviewed, in order to obtain clinical, demographic and cost data: age, anticoagulation indication, risk factors and comorbidities, disability, occupation, salary, means of transportation to the anticoagulation clinic, home address, need to attend the clinic with a companion, companion’s occupation and salary. The categories of employment status used were: employee (defined as a person working for an employer, person or entity, receiving in return a cash compensation, including domestic workers),¹⁶ self-employed (defined as a person who was the owner of his business),¹⁶ unpaid worker or unemployed.

All patients were followed up for a minimum period of four weeks (maximum interval between the consultations, in accordance with the protocol), with assessment of INR tests, warfarin dosage, thromboembolic or hemorrhagic complications and hospitalizations. The data-gathering for this study did not affect the frequency of consultations or warfarin dosage, which were both at the attending physician’s discretion.

The quality of anticoagulation control was assessed by calculating the length of TTR, using the linear interpolation method of Rosendaal.¹⁷ The CHADS2-Vasc score, which is a clinical prediction rule for estimating the risk of stroke in patients with non-valvular atrial fibrillation, was used too.