Determinants of adherence to disease modifying anti-rheumatic drugs in White British and South Asian patients with rheumatoid arthritis: a cross sectional study

Rheumatoid arthritis (RA) is a chronic inflammatory disease characterized by an erosive synovitis [ 1], which can result in joint damage, loss of joint function [ 2], reduced life expectancy [ 3] and increased sickness absenteeism [ 4]. To reduce the risk of joint damage and functional impairment, the National Institute for Health and Clinical Excellence (NICE) [ 5] has recommended the timely use of disease-modifying anti-rheumatic drugs (DMARDs), ideally in combination and commenced within the first three months of symptom onset [ 5]. A high degree of adherence by patients to their prescribed regimen is necessary for optimal outcomes [ 6, 7]. However, poor adherence to drug regimens remains a significant barrier to improving clinical outcomes in RA [ 8] with only 58–82 % of RA patients adhering to their DMARDs [ 8]. Non adherence can occur due to practical factors, such as difficulty opening medication packaging and perceptual factors such as doubts about personal need or concerns about potential side effects [ 9]. Some patients experience inefficacy while others have to stop taking DMARDs because of side effects [ 10, 11]. Adherence to treatment may be influenced by the patient’s social background, by their beliefs about their illness representations and beliefs about treatments [ 12].

Evidence suggests that beliefs about medicines that drive non-adherence may be more prevalent in some ethnic groups [ 13]. Whilst there are recognised differences in beliefs about medicines, the literature describing adherence levels is scarce amongst South Asian RA patients. Our previous research has shown that, South Asian RA patients hold more negative beliefs about DMARDs than White British RA patients [ 14] and prefer traditional medicines, such as Ayurveda, as opposed to conventional therapy [ 15, 16]. Moreover, our findings suggested that patients’ evaluations of prescribed DMARDs were influenced by how they judged their personal need for treatment relative to their concerns about potential adverse effects of treatments. We do not, however, know the extent to which these and other beliefs about medicines impact on medication adherence in South Asian patients.

Other studies demonstrating an association between beliefs about medicines and adherence (e.g. in asthma [ 17], HIV [ 18] and in RA [ 19]), have mainly been conducted amongst Hispanic groups or European populations. Furthermore, the literature shows that patients’ views about specific prescribed medicines (necessity beliefs and concerns) are influenced by more general beliefs about pharmaceuticals as a whole and by common-sense understandings of the illness and symptom expectations and experiences [ 17, 20]. In addition, receiving adequate information about medicines may also be crucial in patients’ decision making [ 21]. Thus, we wanted to identify potential determinants of adherence to disease modifying anti-rheumatic drugs (DMARDs) including an assessment of the influence of beliefs about medicines and satisfaction with information provided about DMARDs and compare determinants of adherence between RA patients of White British and South Asian [ 9].

This study was conducted in the outpatient Rheumatology departments of Sandwell and West Birmingham Hospitals NHS Trust, Heart of England Foundation NHS Trust and University Hospitals Birmingham NHS Foundation Trust, UK. Consecutive patients with RA were approached during their normal routine rheumatology appointments. To reduce interview bias, the researcher did not approach any patients who were under her care. The researcher approached patients while they were waiting to see their consultant or nurse specialist and discussed details of the study with them. If patients expressed an interest in taking part, they were given a Patient Information Sheet outlining the study and time to ask questions before being asked for their consent. Those patients who required more time to decide were given the researcher's phone number and asked to contact her if/when they decided to participate. In this situation, an additional visit was required on the part of the patients to complete the study forms. Patients were recruited if they: (1) Self-defined themselves as being of either White British or South Asian origin and in addition for ‘South Asian’ origin three or more grandparents born in India or Pakistan; and for ‘White British’ patients had three or more grandparents born in the UK or Ireland as outlined in our published protocol. This approach was used in our previous work [ 13, 22]. (2) Fulfilled classification criteria for RA [ 23]. (3) Had been taking at least one DMARD for over 3 months according to their medical records. This cut off was chosen to ensure that participants had a chance to experience taking DMARDs. A number of questionnaires were used to collect data from patients. These were the following;

In addition, data on socio-economic variables were collected (for example age, gender, occupation and ethnicity) along with clinical data including the disease activity score (DAS). Felson et al. [ 30] the DAS28 data were extracted from routine follow up clinics around the time when patients took part in the study (within 1–2 months), the justification for their use in this study has been outlined in our study protocol [ 22].

To accommodate non-English speakers, all questionnaires were translated into Punjabi, Urdu and Hindi using established guidelines [ 31]. The translations were audio recorded. In addition, English versions of the questionnaires were audio recorded and those who read and spoke English were given a choice of either reading the questionnaires or listening to the audio version. There were 42 patients who requested the audio versions of the questionnaires (30 who required the Punjabi, Urdu or Hindi translation and 12 who were from a White background and requested the English audio tape to be played). Where the audio version was used, responses were indicated by patients and the researcher recorded the patient’s verbal response on the questionnaires. The Cronbach’s alpha between the responses given by patients who filled in the questionnaires themselves and patients who listened to the audio version of the questionnaire and for whom the researcher marked the patients’ responses on the questionnaire were checked for reliability of the responses. There were no inconsistencies between responses. Reliability was adequate for both English and non-English versions.

The Index of Multiple Deprivation (IMD) scores is used widely in England as a measure of deprivation. These scores are derived from patients’ postcodes to measure deprivation, higher scores indicating a higher level of deprivation. They are based on government statistics rating the overall deprivation of small areas (containing approximately 1500 people) by combining a number of deprivation indicators such as local crime, disability, income, education and housing [ 32].

The study was approved by the South Birmingham Research Ethics Committee and written consent was obtained from all participants.

This study is the first to show lower self-reported adherence amongst South Asian compared with White British RA patients. Lower self-reported adherence to DMARDs was associated with dissatisfaction with information about side effects (SIMS potential problems) in all patients. There was an interaction between ethnicity and dissatisfaction with information about both [ 1] potential problems associated with DMARDs (SIMS potential problems) and [ 2] how DMARDs work to control the condition (SIMS action and usage), such that dissatisfaction with information about the action and usage of and potential problems associated with DMARDs was a greater predictor of adherence scores in South Asian patients than in the White British patients. The adherence score was also associated with both specific and general beliefs about medicines. Patients who rated their concerns about DMARDS as high relative to their ratings of their personal need for DMARDs to control RA and maintain present and future health, reported lower self-reported adherence. DMARD adherence scores were also correlated with more negative views of medicines in general, with low adherence scores associated with a perception that medicines are fundamentally harmful and overused by doctors. The level of satisfaction with information correlated with negative beliefs about medicines and illness representation of their RA. South Asian patients had higher levels of satisfaction with information about DMARDs if they had a higher degree of personal control over symptoms.

Previous studies investigating the beliefs about medicines held by RA patients also found that patients had strong concerns about potential side effects of DMARDs [ 12, 19, 33]. Neame and Hammond [ 12] reported concern scores to be associated with non-adherence and our findings suggest that concerns about potential adverse consequences of DMARDs may be particularly prevalent in South Asian patients. This is consistent with our previous work where South Asian patients reported higher concerns about their DMARDs [ 14]. In another RA study, Treharne et al. [ 34] found that strong beliefs about the necessity of medications and believing medications not to be harmful predicted higher self-reported adherence but data were only available for White patients. In common with a previous study of medication beliefs and adherence in RA, we found no association, in our multivariable analysis, between self-reported adherence and sociodemographic factors (age, gender, level of education) or whether English was spoken by the patient. A study conducted in Bradford, UK, [ 35], suggested that the difficulty communicating in English experienced by some first-generation South Asian females was a barrier to understanding the disease process and the need for long term DMARD therapy. As a result, in that study, South Asian patients discontinued their DMARDs sooner than the non-South Asian population however, there were limited data on clinical outcomes. Although the DAS28 scores were slightly lower in the South Asian patients, it is difficult to draw significant conclusions related to disease severity based on a single DAS28 score. Longitudinal work is required to measure long term outcomes.

Our results suggest that dissatisfaction with information may occur because patients’ rationale for the long term use of DMARDs may not match with that of the health professional [ 17, 24, 36]. For example, the South Asian patients in our study who viewed RA to be a short lived condition may need to be provided with a convincing rationale for taking long-term treatment consistently even when their RA symptoms fluctuate. The association between beliefs and adherence seen within the current sample is consistent with theoretical predictions regarding the importance of beliefs about medicines in patients with RA [ 22]. These have been described in relation to the literature in other disease areas and the findings provide further support for the Necessity-Concerns framework in non-adherence, which suggests that these common-sense appraisals of treatment can impact on adherence [ 37]. Furthermore, Horne and Weinman [ 17] for example, reported that patients with asthma who were non-adherent had more doubts about the necessity of their medication and concerns about its adverse effects and believed asthma had a more negative impact on their life. Petrie et al. [ 38] demonstrated that it is possible to alter illness behaviours through targeting illness perceptions by providing a common-sense rationale for treatment and illness. Beliefs held by RA patients about treatment might arise from a range of factors including personal experience, illness representations and culture, as well as from information provided by healthcare professionals [ 39]. Furthermore, data in studies of RA [ 35], cardiovascular disease [ 40– 42] and diabetes [ 43– 47] in South Asian patients have cited cultural factors as an influence on patients’ response to illness and treatments. Work is now required in RA to build interventions that are based on theoretical models. For example, using the Necessity-Concerns framework and illness representations model at early stages of the diagnosis and initiation of treatment, may help to identify behaviours that influence decisions to take DMARDs and reduce non-adherence behaviours early.

Our study has a number of limitations including the fact that adherence was self-reported. We acknowledge that using a single approach to collect data on adherence is a limitation of this study. It is widely recognised that all individual approaches to measuring adherence have their specific limitations. For example, pharmacy refill data only index whether patients collect their medication, not whether they take it [ 9], while electronic monitoring methods can be expensive and inconvenient for patients to use (e.g. due to the size of pill caps [ 9]). The methodology to be used to measure adherence in the present study was discussed with our Patient Research Partners who recommended a self-report strategy [ 22]. Future studies in this population may need to combine a self-report measure with other techniques [ 48]. Secondly, this is the first study to have used a number of questionnaires (SIMS, IPQ and MARS) that were independently translated into three languages for the South Asian population. It is possible that some views specific to this population are not captured via these questionnaires. For example, in our previous qualitative work, patients’ views about disease, medicines and desired outcomes were influenced by their health beliefs [ 14, 49]. Furthermore, patients who responded to questionnaires via audio tapes could have missed the opportunity to record their own responses. Thirdly, this study was cross-sectional, preventing us from drawing conclusions regarding which factors were causally related to non-adherence especially the DAS scores. Fourthly, patients’ views about taking medications for other co-morbidities were not recorded; we acknowledge that this may have affected the views about taking DMARDs and would be an interesting issue to explore in future research. Finally, data were not collected on the delay from the time their RA began in patients commencing DMARDs; this could have been an important factor in explaining the different patterns of adherence as we have previously shown that RA patients of South Asian origin delay seeking medical help for longer than non-South Asians patients [ 15].

Despite these limitations, this study provides novel and useful insight into RA patients’ poor adherence in the two ethnic groups studied.

In conclusion, non-adherence to DMARDs was associated with patients’ beliefs about DMARDs, their illness representations and views about medicines in general together with their satisfaction with the type and amount of information they had received about DMARDs. This varied between the two ethnic groups. Our data suggest the following recommendations for clinical practice; (1) Clinicians should engage with individual patients to identify specific factors that may be responsible for poor adherence behaviours. (2) Clinicians should ask patients about medication adherence during every consultation. (3) Clinicians should use tailored educational materials that provide an in-depth but comprehensible explanation of RA, the rationale for using DMARDs to control disease activity in RA and the consequences of poor adherence.