Publicatie datum

Self-reported intentional and unintentional non-adherence to medication in a general practice population.

Dijk, L. van, Dulmen, S. van, Sluijs, E., Heerdink, R., Ridder, D. de, Bensing, J. Self-reported intentional and unintentional non-adherence to medication in a general practice population. European Journal of Public Health: 2006, 16(Suppl. 1) 217. Abstract. 14 th Eupha conference "Politics, Policies and /or the Public's Health", Montreux, 16-18 November 2006.
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Background: Non-adherence to medication is a major public health problem all over the world. Poor adherence to medication regimes accounts for substantial worsening of disease and an increase in health care costs. Few studies on non-adherence distinguished between intentional and unintentional non-adherence, although it can be argued that these are two different phenomena. While unintentional non-adherence can be considered as non-planned behaviour, intentional non-adherence refers to a process in which the patient actively decides not to follow the prescriber’s recommendations. The objective of this study is (i) to assess the proportion of chronic medication users who do not adhere to their medication intentionally and unintentionally and (ii) to explore to what extent intentional and unintentional nonadherence are associated with a wide range of patients’ characteristics. Methods: Data were used from the Second Dutch National Survey of General Practice. During this representative survey in 104 Dutch general practices (195 GPs) 12 699 patients were participated in an extensive health interview (response 64.5%). Eligible for inclusion in this study were 3529 respondents who were prescribed medication for continuous use during the 3 months preceding the interview. The outcome measure was a fourcategory variable: (i) fully adherent; (ii) unintentional non-adherent; (iii) intentional non-adherent; and (iv) both intentional and unintentional non-adherent. Using multinomial regression analysis the association between patient characteristics (such as socio-demographics, social support, lifestyle, overall medication use, and health status) and the outcome measure was estimated. Results: Almost two-third of the patients (63.8%) reported to be fully adherent, 17.8% of the patients was only unintentionally nonadherent, 10% only intentionally non-adherent, and 8.4% was both unintentionally and intentionally non-adherent. Age was the strongest correlate for all types of non-adherence: younger patients were less likely to be non-adherent. Women, religious persons and persons who drank no or a little (1/2 glasses per day) alcohol were less likely to be unintentionally non-adherent. For intentional non-adherence it was also found that religious persons were less likely to be non-adherent. Smokers had a higher chance of being intentionally non-adherent. The more chronic complaints a person had, the more likely it is that this patient was intentionally non-adherent. Patients who were both intentionally and unintentionally non-adherent were more likely to be young, to have more chronic complaints, and to drink more. Moreover, these patients were more likely to use avoidance as a way of coping with problems. Conclusions: Unintentional non-adherence occurs more frequently compared with intentional non-adherence. Apart from age correlates for unintentional and intentional adherence differed. While unintentional non-adherence was mainly associated with sociodemographic characteristics, having (more) chronic complaints was positively correlated with intentional non-adherence. Therefore, it an be concluded that intentional non-adherence and unintentional non-adherence occur in different patient populations. Therefore, interventions to improve adherence levels should pay attention to the difference between intentional and unintentional adherence. (aut. ref.)