Medication adherence and the risk of severe asthma exacerbations: a systematic review

Pathogenesis and prevention strategies of severe asthma exacerbations in children

PURPOSE OF REVIEW

Exacerbations of asthma in children are most frequently precipitated by respiratory infections with a seasonal pattern. However, management takes little account of the underlying infective or other precipitant abnormality.

RECENT FINDINGS

Interactions between environmental triggers, the airway microbiome and innate immune responses are key determinants of exacerbations. Elevated innate cytokines interleukin (IL)-33 and IL-25, and abnormal molecular responses in the interferon pathway are associated with rhinoviral infections. Exacerbations caused by fungal allergens also induce IL-33, highlighting this as an attractive therapeutic target. An equal contribution of bacterial and viral infection during exacerbations, particularly in preschool children, has become increasingly apparent, but some organisms may be protective. Investigation of mechanisms underlying infection-related exacerbations especially in preschool children is needed.Progressive loss of lung function from exacerbations is most pronounced in children aged 6-11 years, and low FEV1 is now recognized as a key predictor for the development of chronic obstructive pulmonary disease and premature death. Although prevention of exacerbations is critical, suboptimal patient education, prescription and adherence to maintenance therapy, and a lack of predictive biomarkers, remain key unaddressed issues in children.

SUMMARY

Precipitants and predictors of exacerbations, together with the child's age and clinical phenotype, need to be used to achieve individualized management in preference to the current uniform approach for all.

Evaluation of factors affecting adherence to asthma controller therapy in chest clinics in a sub-Saharan African setting: a cross-sectional study

BACKGROUND

Adherence to controller therapy in asthma is a major concern during the management of the disease.

OBJECTIVE

To determine the adherence rate and identify the predictors of low adherence to asthma controller therapy.

METHODS

A cross-sectional study including asthma patients was conducted from November 1, 2012 to May 31, 2013 in 4 chest clinics in Cameroon. The adherence to asthma treatment was rated using Morisky Medication Adherence Scale. A multivariate logistic regression analysis was performed for the identification of factors associated with adherence to asthma treatment.

RESULTS

Among the 201 asthma patients included, 133 (66.2%) were female. The mean age of participants was 41.2 years. Sixty-one (30.3%) of the patients did not visit the chest physician during the last year prior to the study. Asthma was well controlled in 118 patients (58.7%). The prevalence of low adherence rate to asthma controller therapy was 44.8% and the absence of any chest specialist visit within the last 12 months was the only factor associated with the low adherence rate to asthma treatment (OR 5.57 ; 95% CI 2.84-10.93).

CONCLUSION

The adherence rate to asthma controller therapy in Cameroon is low and it could be improved if scheduled visits are respected by patients.

Prescription patterns, adherence and characteristics of non-adherence in children with asthma in primary care

Adherence to treatment remains important for successful asthma management. Knowledge about asthma medication use and adherence in real-life offers opportunities to improve asthma treatment in children.

OBJECTIVE

To describe prescription patterns, adherence and factors of adherence to drugs in children with asthma.

METHODS

Population-based cohort study in a Dutch primary care database (IPCI), containing medical records of 176,516 children, aged 5-18 years, between 2000 and 2012. From asthma medication prescriptions, age, gender, seasonal and calendar year rates were calculated. Adherence was calculated using medication possession ratio (MPR) and ratio of controller to total asthma drug (CTT). Characteristics of children with high-vs.-low adherence were compared.

RESULTS

The total asthma cohort (n = 14,303; 35,181 person-years (PY) of follow-up) was mainly treated with short-acting β2-agonists (SABA; 40 users/100 PY) and inhaled corticosteroids (ICS; 32/100 PY). Median MPR for ICS was 56%. Children with good adherence (Q4 = MPR > 87%) were younger at start of ICS, more often visited specialists and had more exacerbations during follow-up compared to children with low adherence (Q1 = MPR < 37%).

CONCLUSION

In Dutch primary care children with asthma were mainly prescribed SABA, and ICS. Adherence to ICS was relatively low. Characteristics of children with good adherence were compatible with more severe asthma, suggesting that adherence is driven by treatment need or intensity of medical follow-up.

Non-adherence to inhaled corticosteroids and the risk of asthma exacerbations in children

BACKGROUND

Non-adherence to inhaled corticosteroids (ICSs) is a major risk factor for poor asthma control in children. However, little is known about the effect of adherence to ICS on the incidence of asthma exacerbations. The objective of this study was to examine the effect of poor adherence to ICS on the risk of exacerbations in children with asthma.

METHODS

In this nested case-control study using data from the Dutch PHARMO Record Linkage System, children aged 5-12 years who had an asthma exacerbation needing oral corticosteroids or hospital admission were matched to patients without exacerbations. Refill adherence was calculated as medication possession ratio from ICS-dispensing records. Data were analyzed using a multivariable multiplicative intensity regression model.

RESULTS

A total of 646 children were included, of whom 36 had one or more asthma exacerbations. The medication possession ratio was 67.9% (standard deviation [SD] 30.2%) in children with an exacerbation versus 54.2% (SD 35.6%) in the control group. In children using long-acting beta-agonist, good adherence to ICS was associated with a higher risk of asthma exacerbations: relative risk 4.34 (95% confidence interval: 1.20-15.64).

CONCLUSION

In children with persistent asthma needing long-acting beta-agonist, good adherence to ICS was associated with an increased risk of asthma exacerbations. Possible explanations include better motivation for adherence to ICS in children with more severe asthma, and reduced susceptibility to the consequences of non-adherence to ICS due to overprescription of ICS to children who are in clinical remission. Further study into the background of the complex interaction between asthma and medication adherence is needed.

Interventions do not enhance medication persistence and compliance in patients with overactive bladder: a 24 weeks, randomised, open-label, multi-center trial

OBJECTIVES

Anticholinergics are currently the mainstay for the management of overactive bladder (OAB). However, low drug adherence has been noted with these medications. The aim of this study was to determine whether a health education intervention (HEI) could improve drug persistence with anticholinergics in OAB patients.

METHODS

We enrolled 682 OAB patients who were randomly distributed into either the HEI plus fesoterodine (HEI) group or the fesoterodine alone (control) group. The HEI consists of four education sections: understanding OAB disease, dietary control, bladder training and understanding anticholinergics. The primary end-point was the difference in drug persistence between the HEI and control groups at 24 weeks. Persistence was defined as a gap ≤ 30 days between successive prescription pills.

RESULTS

Among the 682 patients, 210 (30.8%) completed 24 weeks of study. Persistence of the HEI group at 6 months was not statistically higher than that of the control group (40.4% vs. 34.9%, p = 0.181). Compliance at 6 months was also similar between the two groups (38.5% vs. 32.5%, p = 0.128). Using OAB symptom score questionnaire, the efficacy of the two groups was not different at each follow-up (p > 0.05). The global response was similar between the two groups. However, the HEI group was more satisfied with treatment than the control group (p = 0.034). The most common reason for discontinuation was satisfaction with the treatment so that they did not need to follow-up, followed by inadequate efficacy in both groups. Adverse events were reported in 12.3% of patients.

CONCLUSIONS

The health education intervention was not effective to increase drug persistence in OAB patients on anticholinergics.

New and future strategies to improve asthma control in children

Symptomatic asthma in childhood has lifelong effects on lung function and disease severity, emphasizing the need for improved pediatric asthma control. Control of pediatric risk and impairment domains can be achieved through increased medication adherence or new therapeutic strategies. Developing electronic monitoring device technology with reminders might be a key noninvasive resource to address poor adherence in children and adolescents in a clinical setting. In patients who have persistently poor control despite optimal medication compliance, newly emerging pharmaceuticals, including inhaled therapies and biologics, might be key to their treatment. However, barriers exist to their development in the pediatric population, and insights must be drawn from adult studies, which has its own unique limitations. Biomarkers to direct the use of such potentially expensive therapies to those patients most likely to benefit are imperative. In this review the current literature regarding strategies to improve pediatric asthma control is addressed with the goal of exploring the potential and pitfalls of strategies that might be available in the near future.

Special considerations--asthma in children

BACKGROUND

Asthma is among the most common chronic diseases of childhood. Management of pediatric asthma requires an understanding of the issues that uniquely effect children. This review provides the reader with the current state and future directions of pediatric asthma.

METHODS

Review of the pediatric asthma literature was undertaken with emphasis on randomized controlled trials and systematic reviews.

RESULTS

The prevalence of pediatric asthma remains elevated and is increasingly being appreciated in select global regions. Effective treatment in any setting begins with a focused medical history that queries key asthma features that inform both diagnostic and monitoring strategies. A thorough medical history may yield comorbid upper airway disorders and allergic triggers that could potentially exacerbate airway inflammation. Pre-bronchodilator and post-bronchodilator lung function testing is a preferable diagnostic strategy to quantitatively assess obstructive pulmonary disease among children capable of performing the testing maneuvers. Pediatric asthmatics who continue to have poor disease control require monitoring of medication adherence and drug delivery techniques, because both are often linked with disease outcomes. Therapeutic strategies in children are notably distinct from adults due to the possible effects of inhaled corticosteroids on reduced bone mineral density and growth. Adolescents may also require more time to address the psychosocial complexities that may complicate the required daily usage of asthma medicines.

CONCLUSION

Asthmatic children are distinct from their adult counterparts due to limitations inherent in the pediatric age group. A unified and evidence-based approach to pediatric asthma may improve clinical outcomes.

A review of standard pharmacological therapy for adult asthma – Steps 1 to 5

The aim of pharmacological therapy for asthma is to improve symptoms and lung function and minimize the risk of asthma attacks. The intensity of treatment is based on the level of asthma control and the potential risk of future deterioration. In the British asthma guidelines, treatments are divided into steps 1 to 5, with each step signifying a need for an increase in therapy in response to symptoms or to prevent exacerbations. Treatments comprise of inhaled or systemic medications. Inhaled therapy includes short-acting and long-acting medication to improve symptoms and inhaled corticosteroids that reduce airway inflammation. Systemic treatments include medications that act on specific biological pathways, such as the leukotriene or immunoglobulin E pathways, or systemic corticosteroids. In choosing a particular therapy, treatment benefits are balanced by the potential risks of medication-related adverse effects. This review will provide a practical guide to the key pharmacological therapies for adult asthma at steps 1 to 5 based on British guidelines and consider future options for new treatments.