Dropping the Ball

When talking about medication and treatment, “compliance” and “adherence” are sometimes used interchangeably. But they’re different: “compliance” is old-fashioned, describing a meek patient blindly following advice from an all-knowing, paternalistic doctor. “Adherence” is a team effort – treatment is decided by the doctor and patient together. Adherence can be defined as the extent to which a patient’s behavior (e.g. drugs, diet, and lifestyle changes) coincides with the clinical prescription. Non-adherence can be defined as either intentional or accidental failure to follow the program created with the physician.

Glaucoma management today is mainly focused on IOP reduction, and there are a number of medical (and surgical) avenues to achieve it. The choices we make as clinicians are a balance of benefits versus risks for that particular patient, and their likelihood of adhering to the management program. But how common is non-adherence? For eye disorders in general, the number is extremely high, at 70–75 percent (1). We might wonder why people don’t adhere to and persist with their programs when it’s clearly in their own interests to do so. The reasons are multifaceted, but it’s clear that many of our patients aren’t taking their medications, and frankly, we’re pretty hopeless at telling which ones. It’s always the “other doctors” who have non-adherent patients, not us! What are the risk factors? According to one study group, only a few patients said that costs, side effects, or other medications presented a barrier (2), even though we know that these factors are important in other patient populations. According to the WHO, the reasons for non-adherence are therapy-, condition-, and patient-related, and influenced by the healthcare system and socioeconomic factors. The take-home message is that there isn’t any one factor affecting adherence, and the factors can change over time.

So what do we do about it? We need to address it at every opportunity by asking open questions, trying to track the prescriptions a patient asks for, following up with people who don’t show up, and in patients who are progressing, considering non-adherence as a possible cause.

There’s also a link between non-attendance and non-adherence. Regular clinic attenders are more likely to be adherent, and vice versa (3). The number of visits seems to be important – a recent study found that four visits a year appears to double the odds ratio of adherence. Missed appointments are easy to spot, and can be minimized be reminding patients of appointments, and following up.

We need to remember that patients won’t reliably tell us what they’re not doing, partly because they don’t want to disappoint us, and partly because, as they quite reasonably say, “How can you expect me to remember what I have forgotten to do?”

There are physical barriers to consider too, i.e., getting the drop from the bottle into the eye. Instillation techniques are infamous for being disastrous – in one study 35 percent of patients in a glaucoma center rammed the bottle in their conjunctival sac and poured the contents until they cascaded down their cheek (4). Another 15 percent were “high-altitude bombers,” hoping for the best, and five percent deliberately put the drop on their cheek and rolled their heads around in an attempt to get it in their eye! Of these patients, 25 percent didn’t succeed and 13 percent didn’t know they had failed.

Missing drops (whether through timing or targeting) are hidden from the doctor, and possibly even the patient. They can be disguised, willfully or inadvertently, and they can be denied. Ultimately, it’s the failure to get the agent to the receptor that leads to a failure to achieve results, resulting in less than optimal outcomes. We need to pay attention to non-adherence, and remind our patients that the drugs we prescribe for them simply can’t work if they aren’t using them.