Medical and Dental Consultantsí Association of Nigeria
Home - About us - Editorial board - Search - Ahead of print - Current issue - Archives - Submit article - Instructions - Subscribe - Advertise - Contacts - Login 
  Users Online: 370   Home Print this page Email this page Small font sizeDefault font sizeIncrease font size

  Table of Contents 
Year : 2020  |  Volume : 23  |  Issue : 3  |  Page : 398-407

Warfarin therapy adherence and health-related quality of life among patients using warfarin in Saudi Arabia

Department of Clinical Pharmacy, College of Pharmacy, Prince Sattam Bin Abdulaziz University, Alkharj, Saudi Arabia

Date of Submission28-Nov-2018
Date of Acceptance04-Dec-2019
Date of Web Publication5-Mar-2020

Correspondence Address:
Dr. F I Al-Saikhan
Associate Professor of Clinical Pharmacy, Riyadh, Alkharj, P.O. Box 137
Saudi Arabia
Login to access the Email id

Source of Support: None, Conflict of Interest: None

DOI: 10.4103/njcp.njcp_608_18

Rights and Permissions

Background: Treatment satisfaction and medication adherence to oral anticoagulant therapy are important measures that often decrease morbidity and mortality. Though warfarin is a frequently prescribed oral anticoagulant, warfarin therapy adherence (WTA) and its impact on overall Health-Related Quality of Life (HRQoL) has not been studied in Saudi Arabia. Objectives: To assess the association between WTA and HRQoL among patients on warfarin in Saudi Arabia. Methods: A prospective, cross-sectional, descriptive study was conducted on 387 patients on warfarin therapy attending an outpatient anticoagulation clinic in Alkharj, Saudi Arabia. WTA was assessed using medication adherence measuring scale (MAMS) whereas HRQoL was measured using World Health Organization QOL-BREF (WHOQOL-BREF). Descriptive and inferential statistics were used to examine patients' demographic characteristics and to determine the association among different variables. Spearman's correlation coefficient was used to determine the association between various study variables. Results: Of the total 387 participants, there were more females than males (n=257, 66.4%, and n=130, 33.6% respectively). The mean adherence score for the study population was 5.86±1.21. Mean HRQoL score for physical health domain, psychological domain, social relationships domain, and environment domain were 62.11±15.53, 68.20±16.11, 64.46±26.19 and 63.43±17.60 respectively. The correlation coefficients for all the four domains of the WHOQOL-BREF vs total mean score of warfarin therapy adherence were 0.124, 0.051, 0.063 and 0.083 respectively indicating a weak positive association between warfarin therapy adherence and physical health domain (P < 0.005). Study results indicate a positive association between WTA and the physical health domain of the WHOQOL-BREF among patients on warfarin. Conclusion: Better warfarin therapy adherence can improve the physical health of patients on warfarin.

Keywords: HRQOL, Saudi Arabia, warfarin, warfarin therapy adherence, WHOQOL-BREF

How to cite this article:
Al-Saikhan F I. Warfarin therapy adherence and health-related quality of life among patients using warfarin in Saudi Arabia. Niger J Clin Pract 2020;23:398-407

How to cite this URL:
Al-Saikhan F I. Warfarin therapy adherence and health-related quality of life among patients using warfarin in Saudi Arabia. Niger J Clin Pract [serial online] 2020 [cited 2020 Apr 7];23:398-407. Available from:

   Introduction Top

Low medication adherence can lead to pharmacotherapy failure and vital organ damage. According to the World Health Organization (WHO), in developed countries, the medication adherence rate in acute patients is just around 50%, whereas in chronic patients it is lower than 50%.[1],[2] Nonadherence to prescribed medications in chronic medical conditions is common as patients need more medications to treat their illnesses. This is more common in geriatric patients because of a decline in their physical and mental health.[3],[4] Irrefutably, poor medication adherence is among the greatest challenges that directly affect patients' health status and daily routine activities.[3],[5] Both decreased daily activities and poor medication adherence in chronic diseases can be further dangerous or even life-threatening if patients take narrow therapeutic window drugs like heparin and warfarin.[5],[6]

Warfarin, the most frequently used oral anticoagulant, requires careful and frequent laboratory monitoring to avoid bleeding complications and obtain optimal therapeutic outcomes.[7] A long-term oral anticoagulant, warfarin is often prescribed to control and prevent various thromboembolic diseases like valvular heart disease, stroke, venous thromboembolism (VTE), and atrial fibrillation (AF).[8],[9] As a matter of fact, because of high inter and intrapatient variability, warfarin is only effective if its therapeutic range is maintained. Conversely, if warfarin blood levels are above or below its therapeutic window, it exhibits greater risks of bleeding and thrombosis respectively.[9],[10] It also causes adverse drug reactions that sometimes require hospital admission, and if the length of hospitalization is increased, it may lead to morbidity and mortality.[11],[12] These extended hospital stays, expensive therapies, and fear of death negatively affect patients' daily activities and, ultimately, result in decreased health status.[13],[14] Moreover, low adherence to warfarin therapy can cause loss of self-esteem, anxiety, depression, inability to function at the workplace, and various other emotional problems resulting in poor health-related quality of life (HRQOL).[15],[16]

HRQOL is individuals' perceived QOL and self-satisfaction that is likely to be affected by their general health status.[17],[18] The HRQOL concept is widely used by the health care professionals (HCPs) to describe various factors other than illnesses that affect patients' overall health status.[17],[18] These days, HRQOL is not only measured in patients but also in healthy individuals to estimate the overall health status of the society, which ultimately helps in designing and implementing health care policies to improve the overall health status of the society.[19],[20] Lower medication adherence, frequent international normalized ratio (INR) checks, lifestyle modifications, diet adjustments, activity restrictions, and fear of excessive hemorrhages are all warfarin characteristics that potentially affect treatment satisfaction and diminish patients' HRQOL. In addition, nonadherence also limits patients' daily activities and mounts unnecessary sources of worries in them, which eventually affects their HRQOL. On the other hand, adequate warfarin therapy adherence (WTA) also helps patients attain significant anticoagulation control, decrease hospitalizations, lessen the frequency of the INR checks, and improve HRQOL.

In the last two decades, numerous studies of warfarin in terms of its usage pattern, adherence, knowledge, anticoagulation control, side effects, and drug and food interaction have been reported in the literature.[20],[21],[22],[23] In fact, appropriate counseling about WTA has been considered an ideal practice for patients using warfarin; however. it is not clear whether WTA has any impact on patients' HRQOL in Saudi Arabia. Furthermore, there is a paucity of information regarding WTA and its effects on HRQOL in patients using warfarin from countries like Saudi Arabia. Few studies are evident in the literature regarding the impact of WTA on anticoagulation control, association of adherence with INR, treatment satisfaction, and association of knowledge and beliefs with anticoagulation control in Saudi Arabia,[24],[25],[26],[27],[28],[29],[30],[31],[32],[33],[34] but none is done regarding the association of WTA and its impact on HRQOL using the WHOQOL-BREF. Therefore, this study was designed to examine the association between WTA and HRQOL in patients being treated with warfarin in Saudi Arabia.

   Experimental Top

Study design, sampling technique, data collection

A prospective, descriptive, and cross-sectional study was conducted at an outpatient anticoagulation clinic of the Prince Sattam Bin Abdulaziz University Hospital in Alkharj, Saudi Arabia. The study was started after official approval from Prince Sattam Bin Abdulaziz University Institutional Review Board (IRB) under PSAU-2016-Pharm-9/2/PI. All PSAU-2016-Pharm-9/2/PIaspects of the study protocol, including information on an individual's background, were strictly confidential and used for research only.

In total, 405 respondents filled out the questionnaire, whereas 18 questionnaires were excluded from the study as they had more than 20% missing data. The remaining 387 respondents were considered for data analysis. Participants were adults (aged 18 years and above), using warfarin from at least 2 months because of any clinical indication, and who had attended the clinic for follow-ups. The period of 2 months is the average time needed to adjust the therapeutic warfarin dose.[35] Patients familiar with Arabic (the national language of Saudi Arabia) were included in the study. Participants from other countries (immigrants without Arabic background), aged below 18 years, pregnant women or planning to become pregnant, having documented psychological issues or mental sickness, and those who did not sign the consent forms were excluded from the study. A written consent according to the declaration of Helsinki was taken from all the participants, and only those who gave written consent were included in the study.

Patients' WTA was evaluated using a self-developed and prevalidated adherence tool comprising of eight questions. This research tool was developed after an extensive literature review. Content validity of the research tool was performed by experts in the field of quantitative pharmacy research. Face validity was done to address obvious problems and check the relevance of the research questionnaire as it appeared to the respondents. Cronbach's alpha (α) was used to determine the average correlation of items or internal consistency to gauge the reliability of the study instrument. Like other adherence tools,[36],[37],[38] all questions were dichotomous (Yes/No), where each “Yes” was given a score of 1 and “No” was given a 0. All the obtained scores against each question for each patient were summed to get a total score, ranging from 0 to 8. A patient who scored <6 was considered having low adherence, a score of 6–7 meant medium adherence, and 8 measured as good adherence.

HRQOL was assessed using the WHOQOL-BREF research tool. This self-administered HRQOL tool is cross-culturally sensitive, which has shown good to excellent psychometric properties. The WHOQOL-BREF tool is comprised of four different domains, namely, physical, psychological, social, and environmental. The WHOQOL-BREF tool explains how respondents reflect each aspect of their life and how problematic or satisfactory they perceive them to be for their total HRQOL. The demographic characteristics measured were gender, age, marital status, educational level, employment status, comorbidities other than cardiovascular diseases (CVDs), and indication and duration of warfarin use. The score of each question for each domain was used to obtain a summarized domain score, and finally, all the scores were transformed linearly according to the provided WHOQOL-BREF questionnaire guidelines (0–100 scale).[39] Higher scores indicate higher levels of HRQOL and vice versa. The Arabic version of the WHOQOL-BREF questionnaire was kindly provided by the WHO officials. A panel of experts reconfirmed the content and face validity of the research instruments in the present study. This study was novel among its types because until now there was no evident study-”using WHOQOL-BREF-”hat evaluated the effect of WTA on warfarin-using patients' HRQOL.

Statistical analysis

Descriptive statistics were used to evaluate the demographic and disease characteristics of the patients. Percentage and frequency were used for the categorical variables, while mean and standard deviation (SD) were calculated for the continuous variables. To confirm the internal consistency of the tool Cronbach's α was used, whereas to determine the normality distribution of the data, the Shapiro–Wilk test and Q–Q plots were used. Independent samples t-test and Pearson's correlation coefficient were used to evaluate correlations (agreements) between demographics and adherence and adherence with HRQOL and its domains. Data from research tools were analyzed using the Statistical Package for the Social Sciences (SPSS) software, version 22.0.

   Results Top

The demographic data of the study are presented in [Table 1]. There was a total of 387 participants with more females than males (n = 257, 66.4% and n = 130, 33.6%, respectively). One hundred and forty-four (36.4%) participants were younger than 35 years of age, whereas two hundred and forty-six (63.6%) were older than 35 years. Nine (2.3%) participants had a primary level of education and 378 (97.7%) had a higher level of education. One hundred and fifteen (29.7%) participants had comorbidities other than CVDs and two hundred and seventy-two (70.3%) had no comorbidity.
Table 1: Demographic characteristics of the study participants (n=387)

Click here to view

[Table 2] presents the mean HRQOL scores for all the four domains of WHOQOL-BREF among the study respondents. The mean score for the physical health domain was 62.11 ± 15.53. The mean scores for the psychological, social relationships, and environment domains were 68.20 ± 16.11, 64.46 ± 26.19, and 63.43 ± 17.60, respectively.

Click here to view

[Table 3] shows the key findings for adherence level among warfarin patients toward warfarin therapy. A total of 136 patients showed poor WTA (<6 score), 228 patients showed moderate WTA (6–7 score), and 23 patients showed good WTA (8 score). The results showed that 317 (81.9%) patients never forgot to take their warfarin, while 70 (18.1%) patients sometimes forgot to take their warfarin. Around two hundred and twenty-seven 58.7% of the respondents never modified or stopped taking their warfarin without telling their doctor, and one hundred and sixty 41.3% modified, cut back, or stopped taking their warfarin without informing their doctor. A total of 73.6% of the patients believed that taking daily warfarin can cause warfarin dependence in them, whereas 26.4% did not fear warfarin dependence. There were mixed findings observed for eight domains of the research tool. The mean adherence score for the study population was 5.86 ± 1.21 and the median score was 6.
Table 3: Overall adherence to warfarin therapy

Click here to view

[Table 4] represents the relationship between mean adherence scores and study participants' sociodemographic attributes. The adherence mean scores for males and females were 05.85 ± 1.17 and 05.86 ± 1.23, respectively. Patients aged <35 years had better WTA (05.94 ± 1.24) than those who were >35 years old (05.81 ± 1.19). The adherence scores increased as the educational level increased, but there was no significant difference found between the two groups (05.44 ± 1.30 and 05.87 ± 1.21, respectively). Those who were on job or doing business were having less adherence than the nonworking group 05.80 ± 1.23 and 05.96 ± 1.17, respectively.
Table 4: Demographic characteristics with differences in adherence scores

Click here to view

[Table 5] shows the Spearman rank-order correlation coefficient scores between HRQOL domains and WTA total scores. The association coefficient between the four domains (physical, psychological, social, and environment) of WHOQOL-BREFvs total score of WTA 0.124, 0.051, 0.063, and 0.083, respectively. A statistically significant positive correlation (P ≤ 0.05) was observed between the physical domain of WHOQOL-BREF vs total WTA score, whereas no statistically significant correlation (P ≥ 0.05) was observed between psychological, social, and environment domains of WHOQOL-BREF vs total WTA.
Table 5: Association between WTA and HRQOL

Click here to view

   Discussion Top

Patient's adherence to warfarin therapy is vital in optimizing therapy outcomes, minimizing drug interactions, and reducing adverse drug reactions.[28] The frequent INR monitoring, patient counseling, dose adjustments, and lifestyle modifications may result in substantial changes in patients' daily life activities that may have a positive or negative impact on the overall HRQOL. Earlier WTA and satisfaction studies that have examined these parameters have found significant improvement or reduction in anticoagulation control, which may affect HRQOL.[40],[41],[42],[43],[44] Consistent with these earlier studies, we also found that the majority of study participants felt that adherence to warfarin therapy caused little improvement in the physical aspect of their daily life.[25] One hypothesis is that better treatment satisfaction could improve adherence[45] and adherence is one of many factors that contribute to achieving good anticoagulation control, which ultimately affects HRQOL.[25]

This study explored the association between WTA and HRQOL within the Saudi population. Another study conducted by Mayet et al. revealed that WTA had no role in achieving better anticoagulation control.[3] Despite its narrow therapeutic window and complications in use, warfarin has been considered as a main oral anticoagulant for several decades.[28],[44],[45] There could be many factors that can affect coagulation control in patients on warfarin therapy.[46] The results of our study are almost in line with the results of another study done by Mayet et al.,[3] where they determined the effect of WTA and INR control. In their study, they reported a WTA mean score of 6.78 ± 1.22, whereas in our study, we found the WTA mean score of 5.86 ± 1.21. In our study, 35.1% of the patients showed poor WTA, 58.9% showed moderate, and only 6% of patients showed good WTA. In other words, more than half of the total patients in this study showed moderate WTA. This very low percentage of WTA can result in numerous complications that can affect the overall treatment plan and therapeutic goals in warfarin patients. Conversely, another study reported a higher percentage of WTA using the Morisky Medication-Taking Adherence Scale-4 (MMAS-4).[24],[47] Ababneh et al. reported that warfarin adherence is directly linked with the patients' warfarin knowledge.[24],[48] Providing proper educational interventions regarding WTA and addressing patients' concerns about the potential side effects of warfarin can significantly improve WTA.[24],[49]

A poor WTA is common with 1-in-5 incorrectly taken warfarin doses even at specialized anticoagulation clinics.[3],[32] A study done by Kimmel et al. reported that 92% of the warfarin patients could not adhere to their medication, showing poor anticoagulation control.[3],[34] Older age, marital status, lower educational level, and unemployment are seen to be independent major risk factors for non-adherence to warfarin therapy.[3],[33] According to our study findings, a difference in the patients' WTA among different age groups was observed. The elderly patients (age >35 years) had a poor WTA score (05.81 ± 1.19) as compared with the ≤35 years-old patients, but this difference is not statistically significant (P = 0.326). In terms of mean knowledge score for the marital status attribute, no statistically significant difference (P = 0.103) was observed between single/separated patients (05.74 ± 1.20) and married patients (05.95 ± 1.21).

Poor medication knowledge and required lifestyle modifications significantly contribute to the economic burden of the diseases. Poor adherence to warfarin therapy and a lack of understanding of the proper use of warfarin are among the major barriers to warfarin therapy management.[1] Poor warfarin therapy knowledge has been significantly associated with poor WTA and anticoagulation control which affects HRQOL.[3],[20],[23],[28],[50] Likewise, good warfarin therapy knowledge and better therapy understandings improve WTA, which can ultimately help achieve good anticoagulation control and better HRQOL.[28],[44],[45],[50] In our study findings, 46.8% of the patients were often fed up with their daily warfarin therapy, whereas 53.2% never skipped their warfarin doses and continued to it take even if their symptoms were controlled.

A study by Balkhi et al. showed a significant association between WTA and patient satisfaction. According to them, patients satisfied with their treatment regimens were two times more adherent to their medication therapy than nonsatisfied patients.[24] Our study found that around 15.8% of the patients faced difficulties in terms of side effects and felt inconvenience while taking their medication every day, whereas around 84.2% of them were quite satisfied with their warfarin therapy and neither faced side effects nor the inconvenience. These findings emphasize the real significance of exploring the factors that link treatment satisfaction with medication adherence and HRQOL. High medication adherence can be achieved through educational interventions and proper medication counseling. Improved HRQOL of the warfarin-taking patients could be achieved by assessing the overall awareness of the warfarin patients about their warfarin and its usage. Various studies have reported that the WTA increases with an increase in recognition of the therapeutic benefits and decreases with an increase in professed treatment barriers.[24],[51] In the literature, only a few studies have determined the association between treatment satisfaction, warfarin adherence, and INR control.[3],[24],[52] Another study done by Samsa et al. reported a strong association between warfarin knowledge, treatment satisfaction level, concerns about side effects, the consequence of missing doses, potential drug-drug interactions, therapy adherence, and INR control.[4],[15]

HRQOL is termed as an individual's perceived QOL demonstrating satisfaction in the areas of life that are affected by health status.[20],[53] It is also used to determine the health states of healthy people to obtain the overall health condition of society.[19],[23] There are a few studies done in Saudi Arabia to evaluate patients' WTA but none is evident to determine the association of warfarin adherence with HRQOL of the warfarin patients. Therefore, the present study was aimed to evaluate the association between WTA and HRQOL among warfarin patients in Saudi Arabia.

Findings from the present study showed a weak positive association between WTA and HRQOL of the warfarin patients. There are few studies which are done in different parts of the world regarding medication adherence, knowledge of chronic diseases and their effects on HRQOL. These studies determine an association (positive/negative) between disease-related knowledge, adherence level, and HRQOL.[3],[17],[19],[20],[23],[24] Nevertheless, to the best of our knowledge and after thorough literature review, the association between WTA and HRQOL is yet to be studied in Saudi Arabia using WHOQOL-BREF. Our study findings suggest that WTA can be further improved if the patients are properly counseled about the best time to take warfarin, the safety of taking other medications that interact with warfarin and the consequences of missing out a dose of warfarin. These findings are in accordance with a study done by Elbur et al.[44] to determine knowledge and satisfaction with anticoagulants in Saudi Arabia. Another study done by Nichola et al. found overall a significant positive association between medication adherence and anticoagulation control by using the MMAS-4.[25] Our study findings are also in accordance with their findings in the physical domain of WHOQOL-BREF as a weak positive association (P < 0.05) was also observed. In our study results, there was no statistically significant association observed between psychological, social and environment domains of WHOQOL-BREF and WTA.

Our study also in line with other studies[41],[54] in terms of forgetting to take their warfarin as in these two studies there were patients who forgot to take their warfarin on-time. In our study around 18.1% of the patients forgot to take their warfarin on-time and they doubled their next dose. These obtained results definitely emphasize the need for proper patient counseling and warfarin-related knowledge to increase WTA among warfarin patients. There could be many reasons which may justify this lack of adherence to warfarin therapy. An important and leading factor is the absence of a standardized health care education program especially for patients using warfarin.[27] Furthermore, usually a very short time is given to each patient by the health care staff in Saudi Arabia which affects patient counseling in large.[27] Our study findings are also in accordance with another study done by Ingre et al., that overall HRQOL did not correlate significantly with adherence and treatment satisfaction. However, in some of the patients, there seemed to be a little weak positive association between medication adherence, treatment satisfaction and improved HRQOL especially in the practical aspects of therapy management.[43]

Our study showed that the majority of the highly educated patients had better adherence score 05.87 ± 1.21 than non-educated or primary level educated patients. These findings are opposite to few other studies[3],[24],[25] where highly educated patients had poor adherence than low-level educated patients but warfarin's adherence association with education level was statistically insignificant. Undeniably, educational interventions regarding proper warfarin usage significantly influence the patient's overall therapy adherence and their perceptions about thromboembolic disorders.[55] Conversely, there are few studies that conflict with our study findings regarding the association of warfarin therapy adherence and level of education. Many other studies also showed a positive correlation between good therapy knowledge scores and level of education which could increase patients' therapy adherence.[45],[50],[56],[57]

An interesting finding was observed regarding working and non-working patients, whereby non-working patients had better adherence regarding their warfarin therapy 05.96 ± 1.17 as compared with working patients 05.80 ± 1.23, but no statistically significant differences were found among them (P = 0.207). These findings are similar to a few other studies[3],[24],[25] where more than half of the warfarin patients had poor adherence but warfarin's adherence association with education level was statistically insignificant. Few other studies done in different countries have reported a significant decrease in HRQOL with different chronic diseases[7],[11],[17],[19],[20],[22],[23] but none of the studies measured the association between warfarin therapy adherence and its effect on patients' HRQOL using WHOQOL-BREF. Our findings only showed a weak positive association in the physical domain and no association in the rest three domains of the WHOQOL-BREF. In the physical domain correlation coefficient “r” was 0.124 (0.015); psychological domain “r” was 0.051 (0.320); social domain “r” was 0.063 (0.217); and environment domain “r” was 0.083 (0.103). There could be many possible reasons for this weak positive association in the physical health domain and improvement in HRQOL and no association of the rest three domains with HRQOL among warfarin patients. HRQOL concept measures a wider range of physical health, psychological, social, and environmental attributes and behaviors of individuals, which are considered vital for the overall management of different diseases.[17],[19] On the other hand, HRQOL is enormously difficult to assess impartially because it depends on various patient-associated and irreversible factors like socioeconomic statuses of the patients, differences in intelligence level, different personality traits, varied political conditions of a country and the nature and duration of the diseases.[20],[23],[58]

Overall, our study findings are similar to various others[3],[24],[25] where more than half of the warfarin patients had poor adherence but warfarin's adherence association with education level was statistically insignificant. The current study evidenced that warfarin therapy adherence has little impact on HRQOL in patients using warfarin in Saudi Arabia. Furthermore, in a few of the studies, it is also evident that an increase in medication adherence can increase overall HRQOL.[25] The evident reason behind this concept is believed that an increase in drug or disease-related knowledge may make patients more aware of their drug usage and disease conditions which might increase adherence and overall HRQOL. The explanations for this significant assumption are multi-factorial.[17],[19] Another study findings also support our hypothesis that an increase in medication adherence can increase overall HRQOL.[25] According to that study findings, if the patients more adhere to their medication therapies, their anticoagulation control, and INR levels improve which affect their overall treatment satisfaction particularly in cases of chronic conditions which further affect their physical health, psychological, social, environmental activities which affect their overall HRQOL.

Unfortunately, in countries like Saudi Arabia, the concept of HRQOL has been understood as an item lent from the social sciences and applied to patient care educational studies i.e. our study. Saudi Arabia has good health care setups for their public but still more sophisticated and specialized interventions and facilities needed to better facilitate and counsel specialized patients like those using warfarin or special needs. All these explored factors have a reflective impact using warfarin patients' HRQOL scores. A contrasting study, done by Locadia et al. did not report statistically significant associations between WTA and anticoagulation control.[25],[59] In another contrasting study, there was also no significant relationship was observed between WTA and anticoagulation control where they used the “pills count method” to measure adherence.[25],[60] This may suggest that various factors such as drug-drug and drug-food interactions, genetic variations in drug metabolism and frequent warfarin dosage adjustments play an important role in WTA. This also suggests that adequate WTA is necessary for obtaining better treatment satisfaction, good anticoagulation control, and good HRQOL. On the other hand, it may not be possible to get better HRQOL when such factors that interfere with warfarin's efficacy and efficiency are present.

Knowledge of warfarin's duration of action, its potential adverse events, drug and food interactions, dietary cautions and regular INR checks play a significant role in improving and achieving the desired therapeutic outcomes which might improve patients' quality of life.[27],[28],[44],[61] In our study 35.1% of the patients showed poor WTA, 58.9% showed moderate and only 6% of patients showed good WTA. Perhaps, more extensive dissemination of treatment guidelines to the medical staff is needed especially with explicit instructions to the practicing pharmacists for the apt counseling of the warfarin patients. The other possible factor involved might be the patient's inability to understand and retain the advice given to them regarding potential side effects and drug interactions.[50],[62] Effective communication, a better understanding of the patient's treatment expectations and appropriate pharmaceutical care plans can play a significant role in achieving better treatment outcomes which may affect patients HRQOL. Furthermore, better WTA of the patients may also be attained if drug-disease information is reinforced by improving patient counseling techniques or the use of some relevant written materials.[50] The best option could be the involvement of the non-physician counselors like clinical pharmacists which will improve patients' knowledge about drug-disease states, medication adherence and treatment outcomes.[27],[28],[50]

   Conclusion Top

The present study showed a positive association between WTA and overall HRQOL. This association is likely to be influenced by numerous factors affecting total HRQOL among patients using warfarin in Saudi Arabia. This study was novel among its types as there was no study evident so far which evaluated the effect of WTA on HRQOL of patients using warfarin using WHOQOL-BREF.

Limitations of the Study

Like the majority of the HRQOL questionnaires, WHOQOL-BREF is also a self-reported study tool and in cases of illiterate patients, the tool is filled with the help of patients' caregivers, nurses or the investigators themselves which may report some biases. In this scenario, data reporting biases may have acted as confounding factors in our study. The findings of this study could help physicians, pharmacists, allied health care professionals, and the family members of the patients to better understand the physical health, psychological, social, and environmental problems patients usually face while using warfarin. This study recommends an extensive psychological exploration either using a qualitative probe, multivariate analysis or factor analysis to obtain accurate, purer, precise, and specific factors affecting total HRQOL among patients using warfarin in Saudi Arabia.


I would like to thank all the staff of the outpatient anticoagulation clinic of the Prince Sattam Bin Abdulaziz University Hospital in Alkharj, Saudi Arabia. This study was funded by the deanship of scientific research at Prince Sattam Bin Abdulaziz University under the research grant number 2019/03/10701.

Financial support and sponsorship


Conflicts of interest

There are no conflicts of interest.

   References Top

Sofa DA, Hadyana S, Keri L, Rizky A. Medication adherence contributes to an improved quality of life in type 2 diabetes mellitus patients: A cross-sectional study. Diabetes Ther 2016;7:755-64.  Back to cited text no. 1
World Health Organization. Adherence to long-term therapies. Evidence for action. World Health Organization. Geneva: Word Health Organization 2003. Available from:  Back to cited text no. 2
Mayet AY. Patient adherence to warfarin therapy and its impact on anticoagulation control. Saudi Pharm J 2016;24:29-34.  Back to cited text no. 3
Gurwitz JH, Field TS, Harrold LR, Rothschild J, Debellis K, Seger AC, et al. Incidence and preventability of adverse drug events among older persons in the ambulatory setting. JAMA 2003;289:1107-16.  Back to cited text no. 4
World Health Organization. Process of translation and adaptation of instruments. WHO 2007. Available from:  Back to cited text no. 5
Woodwell DA, Cherry DK. 2004. National ambulatory medical care survey: 2002 summary. Adv Data 2004;26:1-44.  Back to cited text no. 6
Fang MC, Machtinger EL, Wang F, Schillinger D. Health literacy and anticoagulation-related outcomes among patients taking warfarin. Gen Intern Med 2006;21:841-6.  Back to cited text no. 7
Rose AJ, Ozonoff A, Grant RW, Henault LE, Hylek EM. 2009. Epidemiology of subtherapeutic anticoagulation in the United States. Circ Cardiovasc Qual Outcomes 2009;2:591-7.  Back to cited text no. 8
Wysowski DK, Nourjah P, Swartz L. Bleeding complications with warfarin use: A prevalent adverse effect resulting in regulatory action. Arch Intern Med 2007;167:1414-9.  Back to cited text no. 9
Hylek EM, Skates SJ, Sheehan MA, Singer DE. An analysis of the lowest effective intensity of prophylactic anticoagulation for patients with nonrheumatic atrial fibrillation. N Engl J Med 1996;335:540-6.  Back to cited text no. 10
Tang EO, Lai CS, Lee KK, Wong RS, Cheng G, Chan TY. Relationship between patients' warfarin knowledge and anticoagulation control. Ann Pharmacother 2003;37:34-9.  Back to cited text no. 11
Lancaster TR, Singer DE, Sheehan MA, Oertel LB, Maraventano SW, Hughes RA, et al. The impact of long-term warfarin therapy on quality of life. Evidence from a randomized trial. Boston Area Anticoagulation Trial for Atrial Fibrillation Investigators. Arch Intern Med 1991;151:1944-9.  Back to cited text no. 12
Almeida Gde Q, Noblat Lde A, Passos LC, do Nascimento HF. Quality of life analysis of patients in chronic use of oral anticoagulant: An observational study. Health Qual Life Outcomes 2011;9:91.  Back to cited text no. 13
Barcellona D, Contu P, Sorano GG, Pengo V, Marongiu F. The management of oral anticoagulant therapy: The patient's point of view. Thromb Haemost 2000;83:49-53.  Back to cited text no. 14
Samsa G, Matchar DB, Dolor RJ, Wiklund I, Hedner E, Wygant G, et al. Anew instrument for measuring anticoagulation-related quality of life: Development and preliminary validation. Health Qual Life Outcomes 2004;2:22.  Back to cited text no. 15
Thrombosis prevention trial: Randomised trial of low-intensity oral anticoagulation with warfarin and low dose aspirin in the primary prevention in ischemic heart disease in men at increased risk. The medical research council's general practice research framework. Lancet 1998;351:233-41.  Back to cited text no. 16
Saleem F, Hassali MA, Shafie AA, Atif M, Ul Haq N, Aljadhey H. Disease related knowledge and quality of life: A descriptive study focusing on hypertensive population in Pakistan. South Med Rev 2012;5:47-52.  Back to cited text no. 17
Bredow T, Peterson S, Sandau K. Health-related quality of life. Middle-Range Theory: Application to Nursing Research. 2nd ed. Philadelphia: Lippincott Williams & Wilkins; 2008. p. 273-89.  Back to cited text no. 18
Saleem F, Hassali MA, Shafie AA. A cross-sectional assessment of health-related quality of life (HRQoL) among hypertensive patients in Pakistan. Health Expect 2014;17:388-95.  Back to cited text no. 19
Haq N, Hassali A, Shafie AA, Saleem F, Farooqui M, Aljadhey H, et al. Association between Hepatitis B-related knowledge and health-related quality of life. Trop J Pharm Res 2014;13:1163-8.  Back to cited text no. 20
Roche-Nagle G, Chambers F, Nanra J, Bouchier-Hayes D, Young S. Evaluation of patient knowledge regarding oral anticoagulants. Ir Med J 2003;96:211-3.  Back to cited text no. 21
Beyth RJ, Quinn L, Landefeld CS. A multicomponent intervention to prevent major bleeding complications in older patients receiving warfarin. A randomized, controlled trial. Ann Intern Med 2000;133:687-95.  Back to cited text no. 22
Ul Haq N, Hassali MA, Shafie AA, Saleem F, Farooqui M, Aljadhey H. A cross sectional assessment of knowledge, attitude and practice towards Hepatitis B among healthy population of Quetta, Pakistan. BMC Public Health 2012;12:692.  Back to cited text no. 23
Balkhi B, Al-Rasheedi M, Elbur AI, Alghamadi A. Association between satisfaction with and adherence to warfarin therapy on the control of international normalized ratio: A hospital-based study in Saudi Arabia. Saudi Pharm J 2018;26:145-9.  Back to cited text no. 24
Davis NJ, Billett HH, Cohen HW, Arnsten JH. Impact of adherence, knowledge, and quality of life on anticoagulation control. Ann Pharmacother 2005;39:632-6.  Back to cited text no. 25
Eltayeb TYM, Mohamed MS, Abubaker Ibrahim Elbur AI, Elsayed ASA. Satisfaction with and adherence to warfarin treatment: A cross-sectional study among Sudanese patients. J Saudi Heart Assoc 2017;29:169-75.  Back to cited text no. 26
Al-Omair SF, Musallam NA, Al-Deghaither NY, Al-Sadoun NA, Bayoumy NMK. Compliance with and awareness about long-term oral anticoagulant therapy among Saudi patients in a University Hospital, Riyadh, Saudi Arabia. J Appl Hematol 2016;7:10-6.  Back to cited text no. 27
  [Full text]  
Mayet AY. Association between oral anticoagulation knowledge, anticoagulation control, and demographic characteristics of patients attending an anticoagulation clinic in Saudi Arabia: A cross-sectional prospective evaluation. Trop J Pharm Res 2015;14:1285-91.  Back to cited text no. 28
Al-Saikhan FI, Abd-Elaziz MA, Ashour RH, Langaee T. Anticoagulation therapy: For patients' attitude, knowledge and concerns regarding their effects on international normalized ratios in Saudi Arabia. Int J Pharmacol 2018;14:285-90.  Back to cited text no. 29
Shilbayeh SAR, Almutairi WA, Alyahya SA, Alshammari NH, Shaheen E, Adam A. Validation of knowledge and adherence assessment tools among patients on warfarin therapy in a Saudi hospital anticoagulant clinic. Int J Clin Pharm 2018;40:56-66.  Back to cited text no. 30
Davis NJ, Billett HH, Cohen HW, Arnsten JH. Impact of adherence, knowledge, and quality of life on anticoagulation control. Ann Pharmacother 2005;39:632-6.  Back to cited text no. 31
Platt AB, Localio AR, Brensinger CM, Cruess DG, Christie JD, Gross R, et al. Can we predict daily adherence to warfarin?: Results from the International Normalized Ratio Adherence and Genetics (IN-RANGE) Study. Chest 2010;137:883-9.  Back to cited text no. 32
Cruess DG, Localio AR, Platt AB, Brensinger CM, Christie JD, Gross R, et al. Patient attitudinal and behavioral factors associated with warfarin non-adherence at outpatient anticoagulation clinics. Int J Behav Med 2010;17:33-42.  Back to cited text no. 33
Kimmel SE, Chen Z, Price M, Parker CS, Metlay JP, Christie JD, et al. The influence of patient adherence on anticoagulation control with warfarin: Results from the International Normalized Ratio Adherence and Genetics (IN-RANGE) study. Arch Intern Med 2007;167:229-35.  Back to cited text no. 34
Eltayeb TYM, Mohamed MS, Elbur AI, Elsayed ASA. Satisfaction with and adherence to warfarin treatment: A cross-sectional study among Sudanese patients. J Saudi Heart Assoc 2017;29:169-75.  Back to cited text no. 35
Morisky DE, Green LW, Levine DM. Concurrent and predictive validity of a self-reported measure of medication adherence. Med. Care 1986;24:67-74.  Back to cited text no. 36
Morisky DE, Ang A, Krousel-Wood M, Ward HJ. 2008. Predictive validity of a medication adherence measure in an outpatient setting. J Clin Hypertens (Greenwich) 2008;10:348-54.  Back to cited text no. 37
Brislin RW. Translation and content analysis of oral and written materials. In: Trialdis HC, Berry JW, Editors. Handbook of Cross-cultural Psychology: Methodology. Allyn and Bacon Inc Boston; 1986.  Back to cited text no. 38
Development of the World Health Organization WHOQOLBREF quality of life assessment. The WHOQOL Group. Psychol Med 1998;28:551-8.  Back to cited text no. 39
Lancaster TR, Singer DE, Sheehan MA, Oertel LB, Maraventano SW, Hughes RA, et al. The impact of long-term warfarin therapy on quality of life. Evidence from a randomized trial. Boston Area Anticoagulation Trial for Atrial Fibrillation Investigators. Arch Intern Med 1991;151:1944-9.  Back to cited text no. 40
Barcellona D, Contu P, Marongiu F. Patient education and oral anticoagulant therapy. Haematologica 2002;87:1081-6.  Back to cited text no. 41
Nadar S, Begum N, Kaur B, Sandhu S, Lip GY. Patients' understanding of anticoagulant therapy in a multiethnic population. J R Soc Med 2003;96:175-9.  Back to cited text no. 42
Keita I, Aubin-Auger I, Lalanne C, Aubert JP, Chassany O, Duracinsky M, et al. Assessment of quality of life, satisfaction with anticoagulation therapy, and adherence to treatment in patients receiving long-course vitamin K antagonists or direct oral anticoagulants for venous thromboembolism. Patient Prefer Adherence 2017;11:1625-34.  Back to cited text no. 43
Elbur AI, Albarraq AA, Maugrabi MM, Alharthi SA. Knowledge of, satisfaction with and adherence to oral anticoagulant drugs among patients in King Fasial Hospital; Taif, Kingdom Saudi Arabia. Int J Pharm Sci Rev Res 2015;31:274-80.  Back to cited text no. 44
Khudair IF, Hanssens YI. Evaluation of patients' knowledge on warfarin in outpatient anticoagulation clinics in a teaching hospital in Qatar. Saudi Med J 2010;31:672-7.  Back to cited text no. 45
Taylor FC, Ramsay ME, Tan G, Gabbay J, Cohen H. Evaluation of patients' knowledge about anticoagulant treatment. Qual Health Care 1994;3:79-85.  Back to cited text no. 46
Naderiravesh N, Bahadoram S, Shiri H, Anbohi SZ, Khodakarim S, Langroudi FH. Examining the correlation of adherence to warfarin therapy with demographic characteristic. Iran J Crit Care Nurs 2015;8:103-8.  Back to cited text no. 47
Ababneh MA, Al-Azzam SI, Alzoubi KH, Rababa'h AM. Adherence in outpatients taking warfarin and its effect on anticoagulation control in Jordan. Int J Clin Pharm 2016;38:816-21.  Back to cited text no. 48
Clarkesmith DE, Pattison HM, Lip GYH, Lane DA. Educational intervention improves anticoagulation control in atrial fibrillation patients: The TREAT randomised trial. PLoS One 2013;8:74037.  Back to cited text no. 49
Yahaya AM, Hassali MA, Awaisu A, Shafie AA. Factors associated with warfarin therapy knowledge and anticoagulation control among patients attending a warfarin clinic in Malaysia. J Clin Diagn Res 2009;3:1663-70.  Back to cited text no. 50
Orensky IA, Holdford DA. Predictors of noncompliance with warfarin therapy in an outpatient anticoagulation clinic. Pharmacotherapy 2005;25:1801-8.  Back to cited text no. 51
Sahm L, Quinn L, Madden M, Richards HL. Does satisfaction with information equate to better anticoagulant control? Int J Clin Pharm 2011;33:543-8.  Back to cited text no. 52
Peterson S, Bredow T. Middle-Range Theories: Application to Nursing Research. Lippincott Williams and Wilkins; 2008.  Back to cited text no. 53
Kumar S, Haigh JR, Rhodes LE, Peaker S, Davies JA, Roberts BE, et al. Poor compliance is a major factor in unstable outpatient control of anticoagulant therapy. Thromb Haemost 1989;62:729-32.  Back to cited text no. 54
Hernández Madrid A, Potpara TS, Dagres N, Chen J, Larsen TB, Estner H, et al. Differences in attitude, education, and knowledge about oral anticoagulation therapy among patients with atrial fibrillation in Europe: Result of a self-assessment patient survey conducted by the European Heart Rhythm Association. Europace 2016;18:463-7.  Back to cited text no. 55
Poupak R, Charlotte G, Abbas K, Mark B, Susan RK. Association between patient knowledge of anticoagulation, INR control, and warfarin-related adverse events. J Pharm Tech 2016;32:150-9.  Back to cited text no. 56
Bounda G, Ngarambe C, Ge W, Yu F. Assessment and evaluation efficacy of a clinical pharmacist-led inpatient warfarin knowledge education program and follow up at a Chinese tertiary referral teaching hospital. Arch Pharm Pract 2013;4:168-79.  Back to cited text no. 57
Taichman DB, Shin J, Hud L, Archer-Chicko C, Kaplan S, Sager JS, et al. Health-related quality of life in patients with pulmonary arterial hypertension. Respir Res 2005;6:92-7.  Back to cited text no. 58
Locadia M, Van Geest-Daalderop JH, Sprangers MA, Hutten BA, Prins MH. The relationship between adherence and quality of treatment with vitamin K antagonists. J Thromb Haemost 2004;2:362-3.  Back to cited text no. 59
Laporte S, Quenet S, Buchmuller-Cordier A, Reynaud J, Tardy-Poncet B, Thirion C, et al. Compliance and stability of INR of two oral anticoagulants with different half-lives: A randomised trial. Thromb Haemost 2003;89:458-67.  Back to cited text no. 60
Shrestha S, Sapkota B, Kumpakha A, Acharya U, Sharma R. Evaluation of patients' knowledge on warfarin in outpatient pharmacy of a tertiary care cardiac center. BMC Res Notes 2015;8:429.  Back to cited text no. 61
Wilson FL, Racine E, Tekieli V, Williams B. Literacy, readability and cultural barriers: Critical factors to consider when educating older African Americans about anticoagulation therapy. J Clin Nurs 2003;12:275-82.  Back to cited text no. 62


  [Table 1], [Table 2], [Table 3], [Table 4], [Table 5]


    Similar in PUBMED
   Search Pubmed for
   Search in Google Scholar for
 Related articles
    Access Statistics
    Email Alert *
    Add to My List *
* Registration required (free)  

  In this article
    Article Tables

 Article Access Statistics
    PDF Downloaded39    
    Comments [Add]    

Recommend this journal