A cross-sectional study evaluating the relationship between cortisol suppression and asthma control in patients with difficult asthma

Assessment of adherence to corticosteroids in asthma by drug monitoring or fractional exhaled nitric oxide: A literature review

Background

Although the efficacy of corticosteroid treatment in controlling asthma is widely accepted, its effectiveness is undermined by poor adherence. However, the optimal method for measuring adherence to asthma therapy remains unclear.

Objective

To perform a review of the literature reporting biological, objective methods for assessing adherence to inhaled or oral corticosteroids in asthma; we included studies reporting direct measurement of exogenous corticosteroids in blood, or the effect of adherence on exhaled nitric oxide.

Design

We searched three databases MEDLINE (using both PubMed and Ovid), the Cumulative Index of Nursing and Allied Health Literature (CINAHL) and Web of Science for articles published between January 1975 and July 2020. Quality of the studies was assessed using the National Institute of Health checklist.

Results

From 2850 screened articles, 26 fulfilled the inclusion criteria. Measurement of blood prednisolone with or without cortisol was used in eight studies as a measure of oral corticosteroid adherence, and fractional exhaled nitric oxide (FeNO) in 17 studies for inhaled corticosteroid adherence. Inhaled corticosteroids were measured directly in the blood in one study. By direct measurement of drug levels in the blood, adherence rates to oral corticosteroids ranged from 47% to 92%, although the performance and timing of the test were often not known, making interpretation of findings and serum prednisolone concentrations difficult. FeNO is generally lower in adherent than non‐adherent patients, but no absolute cut‐off can be proposed based on the available data. However, a fall in FeNO following supervised inhaled corticosteroid dosing could indicate previous poor adherence.

Conclusions and Clinical Relevance

Despite prednisolone and cortisol levels commonly being used as adherence markers in clinical practice, further work is required to assess the influence of the dose and timing on blood levels. The promising findings of FeNO suppression testing should be explored in further prospective studies.

Medication adherence in asthma patients

PURPOSE OF REVIEW

Although current asthma guidelines stress the importance of assessing and enhancing adherence to asthma treatment, medication adherence rates in asthma patients are consistently low in practice. In this review, we summarize current literature on method of measurement, prevalence, outcome and intervention of medication adherence in asthma patients.

RECENT FINDINGS

Nonadherence to prescribed treatment continues to be a frequent problem in patients with asthma even in recent years. Objective measurement of adherence should be implemented whenever possible. Review of pharmacy refill data or electronic monitoring of inhaler actuation may be a preferred method to assess adherence. Educational programmes should be specifically designed to address the unmet need and specific reasons for nonadherence for the target population. Large, well designed clinical trials to assess the efficacy of remote electronic monitoring and reminder systems to improve adherence are needed.

SUMMARY

There is an urgent clinical need for systematic, proven methods to assess and address medication nonadherence in asthma patients.

Current treatment of severe asthma

Severe asthma is considered a heterogeneous disease in which a variety of clinical, physiological and inflammatory markers determine disease severity. Pivotal studies in the last 5 years have led to substantial progress in many areas, ranging from a more accurate definition of truly severe, refractory asthma, to classification of the disease into distinct clinical phenotypes, and introduction of new therapies. This review focuses on three common clinical phenotypes of severe asthma in adults (early onset severe allergic asthma, late onset non-atopic eosinophilic asthma, late onset non-eosinophilic asthma with obesity), and provides an overview of recent developments regarding treatment options that are best suited for each of these phenotypes.

Measuring asthma control is the first step to patient management: a literature review

Asthma control is recognized as a critical aspect of the evaluation and management of the disease. Here we evaluate and compare existing instruments for measuring asthma control in an attempt to evaluate their clinical utility. Based on a literature review, we identified validated instruments used to assess asthma control in adults. We examined the specific measurement properties and the strengths and weaknesses of each instrument, and evaluated a single instrument, the Asthma Control Questionnaire (ACQ), more closely as an example, evaluating its applicability in the clinical setting. Our review identified five validated instruments designed to measure asthma control: the Asthma Control Questionnaire (ACQ), Asthma Control Scoring System (ACSS), Asthma Control Test (ACT), Asthma Therapy Assessment Questionnaire (ATAQ), and the Lara Asthma Symptom Scale (LASS). None of the instruments covered all relevant control characteristics, but most were aligned with guideline definitions of control. All instruments demonstrated validity and responsiveness, with some measure of reliability. All instruments were short and easily administered, easy to interpret, and all had evidence to support their use in clinical decision making.

The prevalence of nonadherence in difficult asthma

RATIONALE

With the advent of new and expensive therapies for severe refractory asthma, targeting the appropriate patients is important. An important issue is identifying nonadherence with current therapies. The extent of nonadherence in a population with difficult asthma has not been previously reported.

OBJECTIVES

To examine the prevalence of nonadherence to corticosteroid medication in a population with difficult asthma referred to a Specialist Clinic and to examine the relationship of poor adherence to asthma outcome.

METHODS

General practitioner prescription refill records for the previous 6 months for inhaled combination therapy and short-acting beta-agonists were compared with initial prescriptions and expressed as a percentage. Blood plasma prednisolone and cortisol assay levels were used to examine the utility of these measures in assessing adherence to oral prednisolone. Patient demographics, hospital admissions, lung function, oral prednisolone courses, and quality of life data were analyzed to indentify the variables associated with reduced medication adherence.

MEASUREMENTS AND MAIN RESULTS

A total of 182 patients were assessed. Sixty-three patients (35%) filled 50% or fewer inhaled medication prescriptions; 88% admitted poor adherence with inhaled therapy after initial denial. Twenty-one percent of patients filled more than 100% of presciptions, and 45% of subjects filled between 51 and 100% of prescriptions. Twenty-three of 51 patients (45%) prescribed oral steroids were found to be nonadherent.

CONCLUSIONS

A significant proportion of patients with difficult-to-control asthma remained nonadherent to corticosteroid therapy. Objective surrogate and direct measures of adherence should be performed as part of a difficult asthma assessment and are important before prescibing expensive novel biological therapies.