ADHERENCE

IMPACT OF LOW ADHERENCE

Maximal efficacy of medication -as demonstrated in randomized controlled trials- is usually not achieved in the real-world setting. Patients' low adherence to treatment is one of the main reasons.¹

Low adherence is a widespread problem, particularly in chronic diseases. Reported rates of non-adherence to inhaled medication in patients with asthma or COPD (70-80%) are even higher than non-adherence in patients with chronic diseases, such as diabetes medication, antihypertensives, statins and proton pump inhibitors (50%).² Adherence to inhaled therapies is also worse than adherence to oral, injectable or transdermal formulations in patients with COPD or asthma.³

Non-adherence can be intentional (e.g. denial of diagnosis, embarrassment about using inhaler) or non-intentional (e.g. poor inhaler technique, forgetfulness).² Factors, such as the use of multiple devices, need of polypharmacy or disruptive lifestyle (shift work, frequent flights, family crises), all contribute to the risk of patient non-adherence.² Particularly in COPD, older age is a relevant contributor (reduced cognitive function or dexterity, apathy).²

DEFINITIONS^2,3

Adherence
Extent to which patients act in accordance with the prescribed interval and dose of a treatment regimen

The World Health Organization (WHO) distinguishes
3 types of non-adherence:^4,5

erratic (forgetfulness)
unwitting (lack of knowledge)
intelligent (conscious decision)

Many factors may negatively influence adherence to inhaled medications, for example:

Drug-related²

Not drug-related³

Difficulties with inhaler devices
Complex regimens
(Fear for) side effects
Medication costs

Underestimation of disease severity
Forgetfulness
Inappropriate expectations
Poor supervision, training
or follow-up

Adapted from Mäkelä et al., 2013³ and GINA report 2019⁶

The Ascertaining Barriers to Compliance (ABC) taxonomy
defines 3 essential steps to achieve optimal adherence:^1,2

First Dose

End of prescription

A. (Re)initiation: Does the patient take the first dose?

Yes

B. Implementation: To what extent does the actual dosing correspond with the prescribed regimen over time?

Prescribed regimen

Actual regimen

C. Persistence: What is the time elapsed from initiation to discontinuation?

Prescribed regimen

Actual regimen


	dose taken			dose missed

Adapted from Vrijens et al., 2016

Several methods exist to measure patient adherence to treatment:

patient reports
electronic health records (prescription/dispensing)
electronic monitoring devices

Methods differ in precision (sampling rate in months to minutes), validity of the results (e.g. recall bias) and ease of use by patients and healthcare professionals.¹

In an Italian primary care health database of > 20.000 COPD patients, almost 80% showed poor adherence, calculated as days-on-treatment from the prescription and refill data.

Comorbidity and polypharmacy were associated with poor adherence. More severe COPD patients were more likely to adhere.

Odds ratio

1.29 (1.14-1.46)

p < 0.05 (multivariate analysis)

Odds ratio

1.14 (1.06-1.23)

p < 0.05 (multivariate analysis)

in patients ≥ 65 years

Odds ratio

0.20 (0.07-0.61)

ODDS RATIO

Comorbidity
≥ 2 versus no comorbidity

Polypharmacy
≥ 5 drugs versus no comedication

COPD severity
GOLD stage IV vs. stage I

0	0.25	0.50	0.75	1	1.25	1.50	1.75

1.29

1.14

0.20

Adapted from Vetrano et al., 2017⁷

TIPS TO DISCOVER NON-ADHERENCE

Non-judgmental, neutral language may help to discover non-adherence in your patients.

TIPS TO REMEDY NON-ADHERENCE

Several strategies exist to improve adherence, depending on the specific cause(s) of low adherence:^2,4

Examples

Many patients do not take their inhalers as prescribed. To plan your future treatment, can you tell me how often -would you say- you remember to take your treatment?
Do you think that when you are well you tend to forget to take your treatment?
Do you feel comfortable with this prescription?
Do you have any concern about side effects that you wish to discuss with me?

Non-adherence to inhalation treatment is frequent and may lead to poor symptom control, higher incidence of severe exacerbations, hospitalisations, and increased healthcare expenditure.^2,8