Abstract: Patient’s adherence to medication prescription is a prerequisite for adequate therapeutic response. However, approximately 50% of all people with chronic medical conditions do not adhere to their prescribed medication regimens. Adherence rates in people with Rheumatoid Arthritis (RA) for anti-rheumatic medications are estimated between 30-80%.[1] Non-adherence may have a negative impact on morbidity, mortality and quality of life, with high costs to society. Therefore, improving adherence might be one of the best investments to improve the effectivity of medical treatment.
There is little agreement about the causes of adherence and ways to improve adherence. Many variables have been studied in relation to adherence in chronic somatic conditions. As yet, no variables have been singled out that are consistently related to adherence. Socio-demographic characteristics, and psychological variables do not appear to be strong and consistent predictors of adherence. [2,3] Biomedical and disease characteristics are also weakly related to adherence in a consistent way. [2,3]Less attention is given to the study of adherence from the patient's perspective. However, patients do play an active role in non-adherent behaviour. From the patient’s perspective two types of non-adherent behaviours can be distinguished: unintentional and intentional non-adherence. Unintentional adherence can be due to forgetfulness of the patient, or inability to follow the instructions because of poor understanding of the prescription, regimen complexity, or physical problems. Intentional non-adherence originates in the patient’s conscious decisions not to take the medications as instructed. Patients make this decision based on a cost analysis of the treatment weighed against the perceived benefits. Both types of non-adherence stem from different causes. Therefore, interventions to improve adherence are likely to be more effective if they are tailored to the patient’s primary reason(s) for non-adherence. It comes as no surprise therefore, that no single intervention strategy has been shown to be effective across all patients.[4] This inefficacy could be partly explained by the fact that most studies fail to tailor their intervention to the patient’s primary reason(s) for non-adherence. Furthermore, most adherence interventions include both adherent and non-adherent patients, although adherence can only improve in non-adherent people.
Several theoretical models have been developed to explain health related behaviour. The most widely used model, the Health Beliefs Model, hypothesises that individuals will take action, seek care and comply with health regimens if they regard themselves as being susceptible to the condition in question, if the condition has serious consequences, if the action would be beneficial and if they feel that barriers to action are outweighed by the benefits. [5] Patients undertake a cost-benefit analysis, considering whether their beliefs about the necessity of medication outweigh their concerns about potential adverse effects of taking them. Such beliefs of the patient about the necessity of medication and the concerns about medication can be assessed using the Beliefs about Medicines Questionnaire (BMQ).[6] Most people with RA seem to have positive beliefs about the necessity of their medication. [10] However, levels of concern are high and seem to be related with non-adherence.[10] These data are confirmed in our cross-sectional study with 238 people with RA. In this study only 68% of the patients were adherent with prescribed drugs. We found that 52 % of the non-adherent patients had overall positive beliefs about the necessity of their drug. However 91% of our non-adherent patients has also one or more concerns about potential adverse effects, particularly long term effects. (Table 1) This indicates that interventions to optimize adherence should concentrate on patients concerns rather than the necessity of medication.
In conclusion, interventions to improve adherence should only target patients that are non-adherent. Furthermore, both unintentional and intentional non-adherence should be assessed, and the interventions should be tailored to the individuals primary reason(s) for non-adherence. In order to improve intentional non-adherence, clinicians should be sensitive to personal beliefs that may impact medication adherence, and assess and discuss the patient’s concerns about medication.
Table 1:

Concerns in non-adherent patients	% non adherent patients (strongly) agreeing with concerns mentioned in the BMQ
Worried to take medication	53%
Worried about long-term effects	86%
Medicines are a mystery to me	21%
Medication disrupt my life	13%
Worried about dependacy	42%

References: [1]De Klerk et al.J Rheumatol.1999;26(12):2635.[2]Vermeire et al. J Clin Pharm Ther.2001;26(5):331.[3]Donovan et al.Int J Technol Assess Health Care.1995;11(3):443.[4]Haynes et al. Cochrane Database Syst Rev. 2005;(4)[5]Rosenstock IM. Milbank Memorial Fund Q 1966;44:94.[6] Horne et al. Psychology and Health. 1999(14); 1-24.[7]Neame et al. Rheumatology. 2005;44(6):762.