Understanding patient nonadherence to ICS therapy requires the recognition that there are different forms of nonadherent behaviour with diverse contributory factors. Careful clinical interviewing can reveal these problems and set the stage for identifying appropriate strategies for ameliorating them.

Erratic nonadherence. Perhaps the form of nonadherence that is most common and most acknowledged by patients and providers is doses missed because of forgetfulness, changing schedules or busy lifestyles. Patients who exhibit erratic nonadherence understand their prescribed regimen and would often like to adhere appropriately. However, they find it difficult to comply because the complexity of their lives interferes with adherence, or because they have not prioritized asthma management. Patients who have changing work schedules or chaotic lifestyles may have difficulty establishing the habit of a new medication regimen. For some patients Monday - Friday adherence presents no problem, but weekends or holidays disrupt medication routines. Strategies to improve erratic adherence centre on simplification of the regimen (e.g. once-a-day dosing), establishing new habits through linking (e.g. keeping the MDI next to the toothbrush) and cues and memory aids (e.g. pill organizers).

Unwitting nonadherence. Many patients may be inadvertently nonadherent to the prescribed therapy because they have failed to understand fully either the specifics of the regimen or the necessity for adherence. Studies have found that patients frequently forget instructions given to them by a physician during a clinic visit (23). MDIs, unlike pill bottles, do not usually have attached labels with dosing instructions. In asthma management it is common for patients to misunderstand the difference between PRN medication and daily medication. Or, they may interpret the prescription for "ICS twice every day" as meaning "ICS twice every day - when you have symptoms".

Patients may overuse their inhaled beta-agonist because they have never been given clear guidelines for when and how to adjust controller medications or seek medical assistance when asthma control worsens. The ubiquity of unwitting nonadherence is illustrated by the findings of a study by Donnelly et al. (24). The investigators interviewed 128 Australian parents of children with asthma about their knowledge about the disease, attitudes, beliefs and knowledge of asthma medications. Only 42% of parents had a basic understanding of the mode of action of beta-agonists, 12% for methylxanthines, 12% for cromoglycate and 0% for inhaled corticosteroids. Approximately half of the parents reported that sodium cromoglycate and inhaled corticosteroids were used to prevent asthma attacks, while 40 - 50% were unsure of the mode of usage. Most of the parents reported using antibiotics, antihistamines and decongestants in treating their child's asthma. The authors suggested that this poor parental understanding of asthma medications may result from inadequate communication between doctor and patient and this misunderstanding may contribute to the high prevalence of nonadherence to asthma treatments.

In a study in the Netherlands of adult patients with asthma and patients with chronic obstructive pulmonary disease, Dekker et al. (25) found that 20% of the patients using pulmonary medications admitted that they did not know the prescribed daily dosage. Twenty-nine per cent thought that their regular daily medication was actually to be used "short-term" or "as needed". Only 51% correctly perceived that their medications were to be taken regularly.

Intelligent nonadherence. Sometimes patients purposely alter, discontinue, or even fail to initiate ICS therapy. This deliberate nonadherence is called intelligent nonadherence, reflecting a reasoned choice, rather than necessarily a wise one (26). Patients who feel better may decide that they no longer need to take prescribed medications. Fear of perceived short- or long-term side-effects of ICS may cause some patients to reduce or discontinue dosing. Patients may abandon a therapy because bad taste, complexity or interference with daily life may convince them that the disadvantages of therapy outweigh the benefits. Patients may find that some variation of the prescribed therapy works better than the prescribed by the doctor. Given the well-documented underuse of ICS, the fact that ICS therapy is as successful in the management of asthma as it is, suggests that many patients manage quite well with altered or reduced doses. This deliberate nonadherence, like any other pattern of nonadherence does not necessarily result in worsening asthma. In every clinical practice there are patients who have knowingly altered their prescribed therapy, yet their health professional may never discover this modification. Regardless of the reason for nonadherence to medication, the necessary first step towards addressing the problem is identifying it through effective, open-ended communication between patient and provider. Only careful interviewing and active listening will equip the provider of asthma care with the information necessary to establish and reinforce adherence to appropriate medication. The time constraints placed on clinicians by managed care represent a serious barrier to carrying out this recommendation.