Compliance amongst recipients of warfarin to treat non-valvular atrial fibrillation: a cross-sectional study.

BACKGROUND: Vitamin K antagonists, such as warfarin, are the most prescribed anticoagulation medication for the treatment of non-valvular atrial fibrillation (NVAF). The prevalence of NVAF ranges from 0·5% to 1·0% in the general population. We investigated compliance with warfarin treatment among patients with NVAF in Gaza Strip.

METHODS: This was a cross-sectional study done from January, 2017, to October, 2017, at the Indonesian Hospital, Gaza Strip, occupied Palestinian territory. Eligible patients were those admitted to the medical department who were taking warfarin for NVAF, with or without comorbidities, and aged 20-85 years. Patients taking warfarin for other diseases (eg, antiphospholipid syndrome) were excluded. We developed a questionnaire to assesses patients' knowledge about warfarin therapy. The questionnaire was administered by one clinical pharmacist [HM] in face-to-face interviews to avoid difficulties arising from illiteracy, visual impairment, and technical questions. Laboratory data (international normalised ratio [INR], serum creatinine, random blood sugar, systolic and diastolic blood pressure, and liver chemistry) were obtained from clinical records. Continuous data are presented as the mean (SD) and the categoric variables as numbers and percentages. We used binary univariate analysis to assess relationships between quantitative variables. Significant results had two-tailed p values less than 0·05. All data were analysed using SPSS version 20. The study was approved by the Ministry of Health and Helsinki Committee of Gaza Strip. All patients provided written informed consent.

FINDINGS: 100 patients were enrolled in the study (53% men, 47% women), with a mean age of 55 (SD 7) years. 43% of patients had hypertension, 15% had diabetes, and 42% were smokers. 43% of the patients knew of the risks of warfarin treatment whereas 39% understood the benefits. Only 38% of patients were within the therapeutic INR range of 2-3 and 35% had INR values higher than this range. 66% of patients did not have INR monitored regularly and 28% had no regular contact with health-care providers for INR follow up. 21% of patients did not take their daily dose and 36% had developed haemorrhages; only 4% knew how to deal with this complication. Of those who developed haemorrhages, the most common manifestations were epistaxis (44%) and gastrointestinal bleeding (36%). There were no instances of CNS haemorrhage. We found significant relationships between creatinine concentration, diastolic blood pressure, systolic blood pressure, and INR (all p<0·05) INTERPRETATION: The findings of this study show that most of patients were unaware of the risks and benefits of warfarin therapy. We recommend that an anticoagulation clinic is established to provide INR monitoring and education qualified health-care providers. A limitation of this study was low number of patients, but no funding was available for follow-up. However, the accuracy of data give strength to the results, which are representative of the real-world experience of patients with NVAF in our region.

FUNDING: None.