Association between Oral Anticoagulation Knowledge, Anticoagulation Control, and Demographic Characteristics of Patients Attending an Anticoagulation Clinic in Saudi Arabia: A Cross-Sectional Prospective Evaluation

Purpose: To assess the level of knowledge on warfarin therapy and anticoagulation control, and explore the association between knowledge and anticoagulation control in a section of Saudi population. Methods: A cross-sectional prospective survey was conducted over a 4-week period in 2013 at King Khalid University Hospital outpatient anticoagulant clinic in Riyadh, Saudi Arabia. Adult patients who were either discharged on warfarin or taking warfarin and attending the outpatient anticoagulant clinic for ≥ 6 months were invited to participate in the study. A questionnaire was used to collect the demographic data and knowledge of warfarin therapy (8-item). International Normalized Ratio (INR) readings were obtained from electronic-laboratory database. Good knowledge of warfarin was defined as a score of ≥ 75 % and good (INR) control was defined as ≥ 75 % Time INR in therapeutic range (TTR) calculated using Rosendaal method. Results: A total of 105 patients completed the questionnaire with a response rate of 49.2 %. Seventynine patients (75.2 %) had good knowledge of warfarin (scored ≥ 75 %), but only 35 patients (33.3 %) had good anticoagulation control (TTR ≥ 75 %). An association was observed between patients with no formal education and poor warfarin knowledge (p = 0.012). Smoking history was also linked with warfarin knowledge (p = 0.025). INR control results significantly differed by marital status with divorced/widow status displaying poor INR control (p = 0.028). Lastly, no association was found between good knowledge and good INR control (OR 1.35, 95 %; CI 0.537 – 3.392). Conclusions: The majority of patients seen at the outpatient anticoagulation clinic have good knowledge of warfarin therapy although only a third showed good anticoagulation control. The results indicate no significant association between knowledge of warfarin therapy and anticoagulation control. Studies with a larger sample size are recommended to verify the foregoing results.