Non-adherence in difficult asthma and advances in detection

Abstract

Non-adherence to anti-inflammatory therapies is common in patients referred for specialist assessment at difficult-to-treat asthma services. In the difficult asthma setting, non-adherence to treatment is associated with poor baseline asthma control, increased frequency of exacerbations and asthma-related hospitalizations, as well as increased risk of death. Here, we present a review of the current literature surrounding the prevalence and risks of non-adherence in difficult asthma and we report on current methods of measuring treatment adherence and advances in the detection of non-adherence. We will also explore methods by which non-adherence in difficult asthma can be addressed.

Keywords::

• canister weight
• concordance
• corticosteroids
• dose counters
• exacerbations
• exhaled nitric oxide
• prescription records

Financial & competing interests disclosure

JT Lindsay is supported by grants from Northern Ireland Chest Heart and Stroke Association. L Heaney has received grant funding from Medimmune, Novartis UK, Genentech Inc. and GlaxoSmithKline, has taken part in Advisory Boards and given lectures at meetings supported by GlaxoSmithKline, Merck Sharpe & Dohme, Nycomed, Novartis and Astra Zeneca. He has received support funding to attend International Respiratory meetings (Astra Zeneca, Chiesi). The authors have no other relevant affiliations or financial involvement with any organization or entity with a financial interest in or financial conflict with the subject matter or materials discussed in the manuscript apart from those disclosed.

No writing assistance was utilized in the production of this manuscript.

Key issues

• • Difficult asthma is defined as persistent symptoms and frequent exacerbations despite being prescribed asthma therapy at Global Initiative for Asthma (GINA) steps 4 and 5 (i.e., high dose inhaled corticosteroids (ICS), ± maintenance oral corticosteroids (OCS)).

• • Non-adherence to treatment among difficult asthmatics referred to specialist services is common and is associated with poor baseline asthma control, increased frequency of exacerbations and hospitalizations as well as increased mortality.

• • Non-adherence can lead to inappropriate escalation of treatment to maintenance OCS or monoclonal antibody therapy.

• • Patient self-reported adherence tends to be an overestimate. Other objective measures such as dose counters and inhaler canister weighing can also yield overestimations of adherence due to test doses and ‘dumping’, which is when the inhaler is discharged into the air deliberately.

• • Prescription records can be useful but are also prone to measurement error.

• • The fractional exhaled nitric oxide (FeNO) suppression test has been shown to identify patients with difficult asthma, who are sub-optimally adherent to their ICS treatment. In the difficult asthma setting, the use of this test should be considered, along with other objective measures, prior to escalating to monoclonal antibody therapies.

• • A simple concordance interview has been shown to be successful in addressing non-adherence in difficult asthma.