Prevalence of INR Compliance among Patients Referred to MTAC in Miri Hospital
Nor Syazwani Ahmad1, Thomas Ugak1, Ashraf Abdul Mutalib1, Mohd Haziq Razali1 Tseng Lian Der1, Kamarudin Ahmad1
1Pharmacy Department, Hospital Miri
Corresponding author name and email: Kamarudin Ahmad (kamarudin_a @moh.gov.my)
INTRODUCTION: Warfarin is efficacious when anticoagulation levels kept within the target range, anticoagulation levels above and below the target range associated with large increases in bleeding and thromboembolic risk.
OBJECTIVE: To identify the relationship between patient demographic factor and compliance towards warfarin therapy.
METHODS: Retrospective cohort study, on patient referred to Warfarin Clinic at Hospital Miri.
Data from Medical Therapy Adherence Clinic (MTAC) database collected from 2012 until Jun 2014. Data collected using patient’s INR records from previous visits. The collected data included: demographic information such as gender, ethnic, and geographical area.
RESULT: 105 warfarin MTAC patients included in this study. There were no significant association between INR adherence and the gender (P=0.742), age (P=0.212), race (P=0.730), and geographic location (P=0.275), with all of the P value suggested >0.05. Among those recruited, it found that only 15 (14.3%) patients can achieve full INR adherence. Iban race found that to be fewer compliance to warfarin therapy among recruited patients, with only 2 (8.7%) of them achieve full INR adherence.
CONCLUSION: In this study, the results suggest that all the variables included in this study did not link to patients' adherence towards warfarin therapy. Therefore, further research with larger
populations in Sarawak should conducted in the future to gain a better understanding towards warfarin therapy. Future investigation should be focus on improving models of patient-physician shared decision making around anticoagulation.
INTRODUCTION
Warfarin sodium is a efficacious drug, but proper levels of anticoagulation are difficult to maintain (1). Although warfarin is efficacious when anticoagulation levels kept within the target range, anticoagulation levels above and below the target range associated with large increases in bleeding and thromboembolic risk, respectively (2).
Poor adherence with medication and deficiency in patient knowledge, factors associated with non-therapeutic treatment results. Therefore, it is importantto assess patients’ adherence to warfarin therapy (3). Adherence is one of many factors that contribute to anticoagulation control.
Patients have big difficulties keeping adequate adherence with warfarin regimens, and this poor adherence has a significant effect on anticoagulation control(4). Despite concerns about the potential effect of inadequate warfarin regimen adherence, the effects of inadequate adherence on anticoagulation control have not been rigorously and quantitatively evaluated (5).
Adhering to prescribed recommendations during treatment is essential, but managing and educating patients with low literacy skills is a challenge for health care providers (6). The patient’s knowledge on warfarin has shown to be a determinant of anticoagulation control and patient education and counselling is an integral component of a successful warfarin therapy.
Several factors could play a role on the patient’s knowledge on warfarin therapy, adherence to its treatment and overall management of the therapy. A multidisciplinary education programme may improve the patient’s knowledge on warfarin therapy, drug adherence, as well as adherence to medical advice (7).
Malaysia, a multiracial Southeast Asian nation with Malay, Chinese, and Indians as the majority, is an entity with cultural diversities and distinctive genetic variability among the
several races. These diversities have important clinical implications on how therapeutic agents with genetic polymorphism such as warfarin, should be used in practice, as well as the impact of cultural practices and knowledge on warfarin therapy. There is no published data on prevalence of warfarin compliance and association with demographic profile in Malaysia, thus this study will aim to unearth those factors (8).
Patients who were on long-term anticoagulation with warfarin often faced with issues on their treatment. The continued use of warfarin challenged by the complex pharmacology and inherent risk of adverse results therefore satisfactory knowledge on warfarin was very important.
The final aim of anticoagulant therapy is to keep the INR within accepted range and thus prevent complications because of the disease as well as because of anticoagulant therapy. Therefore, the purpose of this study is to find out the prevalence of patients international normalised ratio (INR) is within range. This study also acts as a first step to improve the quality of anticoagulation therapy and patient care in Miri General Hospital. Our aim is to identify the relationship between patient demographic factor and compliance towards warfarin therapy. In the long-term, it can be a document for the source of information on the level of knowledge of patient who is on warfarin, to encourage a new approach, and focus attention on interventions to promote patients knowledge and improve adherence to warfarin therapy and to prevent complications.
METHODS
This study was a retrospective cohort study, on patient referred to Warfarin Clinic at Hospital Miri. Data from Medical Therapy Adherence Clinic (MTAC) database collected from 2012 until Jun 2014.
Data collected using patient’s INR records from previous visits. The collected data included: demographic information such as gender, ethnic, and geographical area. The patients’
source of information on their warfarin therapy obtained by accessing the warfarin records. The patient’s adherence to warfarin therapy accessed through previous assessment by MTAC pharmacist.
Adherence to warfarin therapy will determined by three most recent INR of the patient recruited. INR Adherence defined as full adherence (three most recent visits with all INR within range) and non-adherence (any of three most recent visits with INR not within range). INR level will determined as within range or not within range. Different warfarin indication will have different target INR.
The patient’s medical profiles were then further reviewed to determine the indication of warfarin therapy. The three most current INR values reviewed and compared with target INRs specified in the local anticoagulant protocol. The anticoagulation protocol provided guides for health care providers in-patient management and ensured uniformity and continuity of service.
All eligible patients included in this study were those who on warfarin therapy and had been to the anticoagulation clinic for at least 3 visit without missing appointments. The medical records of the selected patients then reviewed to assess the overall management of warfarin therapy, including the 3 most recent INRs recorded and warfarin doses prescribed. Patients divided into 2 groups based on their place of residence, i.e. rural and urban area. Urban area defined as patients those who live within 10km radius from the city centre, Rural patients are those who live beyond 10 km radius from the city centre.
STATISTICAL ANALYSIS
Descriptive statistics used to present the data on demographic characteristics such as age, sex, race, indication of warfarin therapy, and occupation of patients. Categorical variables were expressed as percentages and frequencies. Cross tabulation, Pearson chi-square test and Fisher’s exact test used to examine the relationship between demographic characteristics with adherence to warfarin therapy. A P level of <0.05 will show the significance. All statistical analyses performed using SPSS software, version 11.0.
RESULT
During data collection, 105 warfarin MTAC patients from hospital Miri included in this study. Among the subjects, 66 (62.8%) were males. The majority, 61 (58.1%) patients were
aged >55 years old. The racial breakdown for the patients was Chinese, Malay, Native Sarawak and Indian. Most of the patients (65.7%) lived around 10km radius from urban area. Relationship between demographic characteristics and INR adherence presented in Table 1.
From the result shown in Table 1, it found there were no significant association between INR adherence and the gender, age, race, and geographic location, with all the P value showed >0.05.
Among those recruited, it found that only 15 (14.3%) patients can achieve full INR adherence. Of the patients that achieve full INR adherence (15 patients), most of them were male (66.6%), >55 years (60%), Chinese (40%) and from urban area (53.3%). Also, it noted that none of the patient aged between 26 and 35 years old able to achieve full INR adherence. Iban race found that to be less compliance to warfarin therapy among recruited patients, with only 2 (8.7%) of them achieve full INR adherence.
Table 1: Factors (categorical variables) associated with INR adherence
Variable n No INR
adherence n (%)
Full INR adherence
n (%)
X2statistica (df)
P value
Gender
Male 66 56(84.8) 10(15.2)
Female 39 34(87.2) 5(12.8) 0.11(1) 0.742a
Age
16-25 4 2(50.0) 2(50.0)
26-35 5 5(100.0) 0(0.0)
36-45 10 8(80.0) 2(20.0)
46-55 25 23(92.0) 2(8.0)
>55 61 52(85.2) 9(14.8) - 0.212b
Race
Malay 25 22(88.0) 3(12.0)
Chinese 37 31(83.8) 6((16.2)
Indian 1 1(100.0) 0(0.0)
Others 19 15(78.9) 4(21.1)
Iban 23 21(91.3) 2(8.7) - 0.730b
Geographic location
Urban 69 61(88.4) 8(11.6)
Rural 36 29(80.5) 7(19.5) 1.19(1) 0.275a
aChi-square test of independence bFisher-exact test
DISCUSSIONS:
INR not correlated with increasing age. No significant difference noted between the older and younger patients on any characteristics (9). Gender not significantly related to the odds of a reduced INR and prothrombic measures (10). This may because of both genders have the tendency to comply with medications regardless of the gender. As some may suggest that women always comply towards their medications, this data proved that gender did not affect INR reading thus compliance towards medications. There was not much study about the relationship between age and gender with INR result.
Management of oral anticoagulant with warfarin was far from being ideal, even in urban areas (11). This might be because of high education that they received which might lead to independent decision making or decreased trust in physicians. Besides, active employment of urban population might contribute to competing time interest and results in INR reading being affected (11).
This research found that race or ethnicitydid not have an impact on patient’s INRlevel or adherence. The possible reason for these findings is because counselling given in multi-language such as Iban, Malay and Chinese and the other races have a better understanding of it. A study which carried out in UK showed there were no significant differences in patient’s knowledge on warfarin, although certain minority groups did have a lower score because of their inability to understand the counselling given (12). The findings in this research cannot compared with the study in UK because of the cultural differences; however, being the first study in Malaysia which looked at ethnicity and patients’ knowledge and their correlation with INR level, these findings can be used as a stepping stone for future research.
There is no association between demographic factors and compliance towards warfarin, demographic factors cannot be use as it is difficult to predict the level of compliance towards warfarin. Study done by Orensky suggested that drug regimen may affect the noncompliance towards warfarin (13). Another study done by Seliverstov suggested that psychosocial issues
such as depressive symptoms, attitudinal and behavioural factors, cognitive function, lack of social support, limited English proficiency, and health illiteracy have associated with warfarin non-compliance among patients in anticoagulation clinics (14).
LIMITATION OF THE STUDY:
Even this study limited by its cross-sectional nature but it does not rely only on data acquired, but all medical records for patients reviewed for specific information for example, past medical history, present medications and others. In addition, there is the possibility that patients had different amounts of education; especially that this research conducted at Miri General Hospital setting, where Miri's population consists of multi-ethnicity such as Iban, Chinese, Malay, Berawan, Kedayan, Lun Bawang, and a handful of Eurasians and other indigenous groups. Another potential bias could have been the language barrier in non-Malay speakers especially from other races for example, Chinese patients that limit the inclusion of this group in our study.
CONCLUSION:
Warfarin therapy reduces morbidity and mortality related to thromboembolism. Yet adherence to long-term warfarin therapy remains challenging because of the risks of anticoagulant associated complications and the burden of monitoring. In this study, the results suggest that all the variables included in this study did not relate with patients' adherence towards warfarin therapy. Therefore, further research with larger populations in Sarawak should be conducted in the future to gain a better understanding towards warfarin therapy. As such, future investigation should be focus on enhancing models of patient-physician shared decision making around anticoagulation.
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Appendix:
Data Collection Form
