Difficult asthma: defining the problems

Measuring and reporting treatment adherence: What can we learn by comparing two respiratory conditions?

Medication non-adherence, defined as any deviation from the regimen recommended by their healthcare provider, can increase morbidity, mortality and side effects, while reducing effectiveness. Through studying two respiratory conditions, asthma and tuberculosis (TB), we thoroughly review the current understanding of the measurement and reporting of medication adherence. In this paper, we identify major methodological issues in the standard ways that adherence has been conceptualised, defined and studied in asthma and TB. Between and within the two diseases there are substantial variations in adherence reporting, linked to differences in dosing intervals and treatment duration. Critically, the communicable nature of TB has resulted in dose-by-dose monitoring becoming a recommended treatment standard. Through the lens of these similarities and contrasts, we highlight contemporary shortcomings in the generalised conceptualisation of medication adherence. Furthermore, we outline elements in which knowledge could be directly transferred from one condition to the other, such as the application of large-scale cost-effective monitoring methods in TB to resource-poor settings in asthma. To develop a more robust evidence-based approach, we recommend the use of standard taxonomies detailed in the ABC taxonomy when measuring and discussing adherence. Regimen and intervention development and use should be based on sufficient evidence of the commonality and type of adherence behaviours displayed by patients with the relevant condition. A systematic approach to the measurement and reporting of adherence could improve the value and generalisability of research across all health conditions.

Asthma and Corticosteroid Responses in Childhood and Adult Asthma

Corticosteroids are the most effective treatment for asthma; inhaled corticosteroids (ICSs) are the first-line treatment for children and adults with persistent symptoms. ICSs are associated with significant improvements in lung function. The anti-inflammatory effects of corticosteroids are mediated by both genomic and nongenomic factors. Variation in the response to corticosteroids has been observed. Patient characteristics, biomarkers, and genetic features may be used to predict response to ICSs. The existence of multiple mechanisms underlying glucocorticoid insensitivity raises the possibility that this might indeed reflect different diseases with a common phenotype.

Nasal airway epithelial cell IL-6 and FKBP51 gene expression and steroid sensitivity in asthmatic children

Background

Many asthmatic patients exhibit uncontrolled asthma despite high-dose inhaled corticosteroids (ICS). Airway epithelial cells (AEC) have distinct activation profiles that can influence ICS response.

Objectives

A pilot study to identify gene expression markers of AEC dysfunction and markers of corticosteroid sensitivity in asthmatic and non-asthmatic control children, for comparison with published reports in adults.

Methods

AEC were obtained by nasal brushings and primary submerged cultures, and incubated in control conditions or in the presence of 10 ng/ml TNFalpha, 10^-8M dexamethasone, or both. RT-PCR-based expression of FKBP51 (a steroid hormone receptor signalling regulator), NF-kB, IL-6, LIF (an IL-6 family neurotrophic cytokine), serpinB2 (which inhibits plasminogen activation and promotes fibrin deposition) and porin (a marker of mitochondrial mass) were determined.

Results

6 patients without asthma (median age 11yr; min-max: 7–13), 8 with controlled asthma (11yr, 7–13; median daily fluticasone dose = 100 μg), and 4 with uncontrolled asthma (12yr, 7–14; 1000 μg fluticasone daily) were included. Baseline expression of LIF mRNA was significantly increased in uncontrolled vs controlled asthmatic children. TNFalpha significantly increased LIF expression in uncontrolled asthma. A similar trend was observed regarding IL-6. Dexamethasone significantly upregulated FKBP51 expression in all groups but the response was blunted in asthmatic children. No significant upregulation was identified regarding NF-kB, serpinB2 and porin.

Conclusion

LIF and FKBP51 expression in epithelial cells were the most interesting markers of AEC dysfunction/response to corticosteroid treatment.

Asthma-like symptoms as a presentation of antiphospholipid syndrome

We herein report a case of antiphospholipid syndrome (APS) primarily presenting with asthma-like symptoms that had been misdiagnosed as severe asthma. Patients presenting with severe asthma symptoms along with systemic thrombosis should be systematically evaluated for APS.

The bronchodilator response as a predictor of inhaled corticosteroid responsiveness in asthmatic children with normal baseline spirometry

RATIONALE

Although inhaled corticosteroids (ICS) are considered first line controller therapy in children with persistent asthma, heterogeneity of the ICS response can be an important clinical problem. The purpose of this study is to determine the value of the bronchodilator response (BDR) in identifying the ICS responder and establish the optimal BDR cut-point that could be particularly useful in the clinic setting when baseline spirometry is normal.

METHODS

Mexican American asthmatic children, 5-18 years, with normal baseline spirometry who required low dose (step 2), or medium dose (step 3) ICS therapy were evaluated by skin prick test for atopy, and pre- and post-bronchodilator spirometry. ICS responders were defined by a ≥7.5% improvement in the FEV1 following 4-6 weeks of therapy. The optimal cut-point was determined by Receiver Operator Characteristic (ROC) curves as the best balance between sensitivity and specificity.

RESULTS

There were 34.8% of the 132 study patients who were ICS responders. ROC curves showed the BDR ≥10% to be an optimal cut-point with sensitivity 46%, specificity 76%, positive predictive value (PPV) 50%, and negative predictive value (NPV) 72%. Atopic females with a BDR ≥10% had a PPV of 73%.

CONCLUSIONS

The composite phenotype of female gender, atopic, and the BDR of ≥10% identified 73% as ICS responders compared to 50% in our overall population with a BDR of ≥10% alone, with minimal false positives. We suggest that the BDR in conjunction with gender and atopic status be considered as potentially useful predictors of the ICS responder, particularly when baseline spirometry is normal.

Adherence: the goal to control asthma

Asthma management requires adequate adherence to many recommendations, including therapy, monitoring of asthma control, avoidance of environmental triggers, and attending follow-up appointments. Poor adherence is common in patients with asthma and is often associated with increased health care use, morbidity, and mortality. Many determinants of poor adherence have been identified and should be addressed, but there is no clear profile of the nonadherent patient. Interventions to improve adherence therefore demand tailoring to the individual by including patient-specific education, addressing patient fears and misconceptions, monitoring adherence, and developing a shared decision process.

Management of severe asthma in children

Children who are referred to specialist care with asthma that does not respond to treatment (problematic severe asthma) are a heterogeneous group, with substantial morbidity. The evidence base for management is sparse, and is mostly based on data from studies in children with mild and moderate asthma and on extrapolation of data from studies in adults with severe asthma. In many children with severe asthma, the diagnosis is wrong or adherence to treatment is poor. The first step is a detailed diagnostic assessment to exclude an alternative diagnosis ("not asthma at all"), followed by a multidisciplinary approach to exclude comorbidities ("asthma plus") and to assess whether the child has difficult asthma (improves when the basic management needs, such as adherence and inhaler technique, are corrected) or true, therapy-resistant asthma (still symptomatic even when the basic management needs are resolved). In particular, environmental causes of secondary steroid resistance should be identified. An individualised treatment plan should be devised depending on the clinical and pathophysiological characterisation. Licensed therapeutic approaches include high-dose inhaled steroids, the Symbicort maintenance and reliever (SMART) regimen (with budesonide and formoterol fumarate), and anti-IgE therapy. Unlicensed treatments include methotrexate, azathioprine, ciclosporin, and subcutaneous terbutaline infusions. Paediatric data are needed on cytokine-specific monoclonal antibody therapies and bronchial thermoplasty. However, despite the interest in innovative approaches, getting the basics right in children with apparently severe asthma will remain the foundation of management for the foreseeable future.

Corticosteroid responsiveness and clinical characteristics in childhood difficult asthma

This study describes the clinical characteristics and corticosteroid responsiveness of children with difficult asthma (DA). We hypothesised that complete corticosteroid responsiveness (defined as improved symptoms, normal spirometry, normal exhaled nitric oxide fraction (F(eNO)) and no bronchodilator responsiveness (BDR <12%)) is uncommon in paediatric DA. We report on 102 children, mean+/-sd age 11.6+/-2.8 yrs, with DA in a cross-sectional study. 89 children underwent spirometry, BDR and F(eNO) before and after 2 weeks of systemic corticosteroids (corticosteroid response study). Bronchoscopy was performed after the corticosteroid trial. Of the 102 patients in the cross-sectional study, 88 (86%) were atopic, 60 (59%) were male and 52 (51%) had additional or alternative diagnoses. Out of the 81 patients in the corticosteroid response study, nine (11%) were complete responders. Of the 75 patients with symptom data available, 37 (49%) responded symptomatically, which was less likely if there were smokers in the home (OR 0.31, 95% CI 0.02-0.82). Of the 75 patients with available spirometry data, 35 (46%) had normal spirometry, with associations being BAL eosinophilia (OR 5.43, 95% CI 1.13-26.07) and high baseline forced expiratory volume in 1 s (FEV(1)) (OR 1.08, 95% CI 1.02-1.12). Of these 75 patients, BDR data were available in 64, of whom 36 (56%) had <12% BDR. F(eNO) data was available in 70 patients, of whom 53 (75%) had normal F(eNO). Airflow limitation data was available in 75 patients, of whom 17 (26%) had persistent airflow limitation, which was associated with low baseline FEV(1) (OR 0.93, 95% CI 0.90-0.97). Only 11% of DA children exhibited complete corticosteroid responsiveness. The rarity of complete corticosteroid responsiveness suggests alternative therapies are needed for children with DA.

[Diagnosis and treatment guidelines for difficult-to-control asthma in children]

Children suffering from difficult-to-control asthma (DCA) require frequent appointments with their physician, complex treatment regimes and often admissions to hospital. Less than 5% of the asthmatic population suffer this condition. DCA must be correctly characterised to rule out false causes of DCA and requires making a differential diagnosis from pathologies that mimic asthma, comorbidity, environmental and psychological factors, and analysing the factors to determine poor treatment compliance. In true DCA cases, inflammation studies (exhaled nitric oxide, induced sputum, broncho-alveolar lavage and bronchial biopsy), pulmonary function and other clinical aspects can classify DCA into different phenotypes which could make therapeutic decision-making easier.

'Difficult asthma': can symptoms be controlled in a structured environment?

OBJECTIVE

Difficult asthma implies persistent asthma symptoms despite therapy with high doses of inhaled corticosteroids. The objective was to evaluate children with difficult asthma in a setting that excludes aggravating factors such as poor treatment adherence and adverse environmental influences.

PATIENTS AND METHODS

Sixty children (> or =6 years) had been referred because of difficult asthma to the rehabilitation centre over a period of 10 years. The diagnosis of poor asthma symptom control was confirmed if exacerbations continued during stay in the centre or if symptoms interfered with daily activities at least 3 times a week.

RESULTS

The median stay at the centre was 5 months. In four patients a diagnosis other than asthma was made. In five patients symptom control remained difficult. In the remaining 51 children, asthma symptoms became well controlled. Many factors contributed to poor asthma control in the home setting: poor treatment adherence (n = 32), parental smoking (n = 22), allergen exposure (n = 10). Psychosocial problems occurred in 36 children. Contributing factors often co-existed. During stay at the centre, lung function improved in the group with well controlled asthma symptoms (P < 0.001) but not in the group with continued poor symptom control. In the majority of children who obtained good symptom control, this persisted in the years following discharge.

CONCLUSION

Of 60 children referred with a diagnosis of difficult asthma, optimal medical management in a structured environment resulted in good symptom control in 51 patients; symptom control remained poor in 5 patients, a diagnosis other than asthma was made in 4 patients.

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.

Severe asthma in childhood: assessed in 10 year olds in a birth cohort study

BACKGROUND

Limited information is available regarding the prevalence of severe asthma in children. The present study aimed at investigating the prevalence of severe asthma in an urban child population; secondarily evaluating the applicability of the chosen definition by clinical characteristics.

METHODS

Children enrolled in the prospective birth cohort; the Environment and Childhood Asthma Study in Oslo; were reinvestigated at the age of 10 years (n = 1019). A representative population based cohort of 616 children [mean age 10.9 (SD 0.9) years] with lung function measurements at birth was used for prevalence estimates, whereas all 1019 children (154 with current asthma) attending the 10-year follow-up were included for verification of the definition of severe asthma. Clinical investigations included spirometry, tests of bronchial hyperresponsiveness, skin prick tests and exhaled nitric oxide. Severe asthma was defined as poorly controlled asthma despite treatment with > or = 800 microg budesonide or equivalent; assessed by a detailed structured interview.

RESULTS

The population point prevalence at age 10 years of current severe asthma was 0.5% (three of 616) and among children with current asthma 4.5% (three of 67). The 10/154 children identified as suffering from severe asthma more often had severe bronchial hyperresponsiveness (PD(20) methacholine <1 micromol) (60%vs 22%, P = 0.015), lower median forced expiratory volume in 1 s/forced vital capacity ratio (93%vs 99%, P = 0.04) and higher body mass index (mean BMI 22.3 vs 18.3, P < 0.001) than nonsevere current asthmatics.

CONCLUSIONS

The prevalence of severe asthma was 0.5% in all 10-year olds, and 4.5% among current asthmatics. The severe asthma definition applied in this study is supported by results of clinical investigations.

Severe chronic asthma

Persistent childhood asthma is more common in females with atopy with an early onset and may result in significant impairment of lung function. Pathological changes in severe chronic asthma in childhood are only partially defined and correlation between pathology, response to treatment and persistence is imprecise. Failure to respond to usual therapies requires careful consideration of differential diagnosis, type of inflammation present, compliance with therapy, and continuing monitoring and re-assessment.

Adesão às medidas de controle ambiental em lares de crianças e adolescentes asmáticos

OBJETIVO: Verificar a adesão às medidas de controle ambiental em lares de crianças asmáticas, através de visitas domiciliares. MÉTODOS: Visitas domiciliares, com observação direta e preenchimento de questionário, foram feitas em 98 lares de crianças e adolescentes asmáticos de quatro a quinze anos, antes e após 90 dias de medidas de controle ambiental serem preconizadas. Foi perguntado aos pais o porquê de não se fazer o controle ambiental. Para a análise estatística foi usado o teste de McNemar. RESULTADOS: O acréscimo na adesão aos diferentes itens pesquisados foi de 11,1%, com variação de -4,1%, para retirada de cortinas (p = 0,63) a +22,6%, para retirada de brinquedos de pelúcia (p < 0,01). A presença de fumantes passivos foi reduzida em 9,7% (p = 0,02). A população estudada tinha renda média mensal de 2,5 salários mínimos. Quando perguntado o porquê de não se adotarem as medidas recomendadas, os motivos principais alegados foram: "falta de dinheiro" (60,1%), "achou difícil de realizar" (6,1%), "não dependia só dela" (4,0%) e "falta de tempo da mãe" (4%). CONCLUSÃO: O controle ambiental nem sempre é realizado e pode ser influenciado por fatores socioeconômicos e culturais.

Management of unresponsive asthma

Difficult asthma is defined as asthma that is not controlled despite treatment with> 800 micro g budesonide or equivalent per day. Poor control is defined as the need for bronchodilators more than three times a week, school absence of more than five days a term, or one episode or more of wheezing each month. Common causes of poor response to treatment include; wrong diagnosis, inappropriate medications or improper inhalation technique, poor adherence to medications and co-morbidity. Steroid resistant asthma is uncommon and estimated to be 1 in 1000-10000 asthmatic patients. If there is no functional improvement to prednisolone 2 mg/kg/day for 2 weeks with adherence checked by measuring serum prednisolone and cortisol levels, a fibreoptic bronchoscopic examination with bronchoalveolar lavage and large airway biopsy should be considered. Eosinophilic inflammation identified on the biopsy in a child who is unresponsive to prednisolone may benefit from alternative anti-inflammatory treatments such as cyclosporin. Neutrophilic infiltration in biopsy may benefit with macrolide antibiotics, 5-lipogenase inhibitors or theophyllines.

Safety of endobronchial biopsy in 170 children with chronic respiratory symptoms

BACKGROUND

There is a paucity of bronchial biopsy data in children. A major limitation is concern over the safety of the procedure. This paper reports the results of efforts to develop a method that is safe and provides adequate specimen for evaluation.

METHODS

170 children aged 2.5 to 16 years with chronic respiratory symptoms were studied under general anaesthesia in an outpatient surgery setting. Bronchoalveolar lavage and biopsies were obtained using a 4.9 mm flexible bronchoscope through a laryngeal mask airway. At least three bioipsies were taken.

RESULTS

No patient required topical adrenaline to control bleeding, nor was there a change in the state of any of the patients. There were no episodes of pneumothorax, haemoptysis, pneumonia, or significant fever. All children less than four years old received a single dose of antibiotic intravenously after the procedure. The average length of time for the procedure was 12 minutes (range 6 to 27). Recovery time averaged 90 minutes. The limiting factor was the ability of the child's airway to accomodate the bronchoscope.

CONCLUSIONS

This report should encourage clinicians to incorporate endobronchial biopsy into the evaluation of children with difficult respiratory problems.

[Difficult asthma in children]

Difficult asthma in children is defined as the persistence of exacerbations or frequent symptoms requiring rescue bronchodilator, or persistent airway obstruction in spite of treatment with inhaled steroid >/= 800 microg/d beclomethasone or equivalent and beta-2 long acting agonist. Management of difficult asthma in children first requires to identify conditions that may mimic asthma, asthma with bad compliance to treatment, and difficult asthma in relation with avoidable factors that worsen symptoms. The pathological bases of genuine difficult asthma remain unknown. Different patterns have been described according to the cells that are involved (eosinophil, neutrophil), the degree of airway remodeling, or the distal localization of the lesions. Difficult asthma requires specialized management including airway inflammation evaluation. Studies on bronchoalveolar lavage and bronchial mucosa biopsies will perhaps help to better understand the pathophysiology and to improve the management.

Difficult asthma in children

Asthmatic children on high dose corticosteroids need to be fully assessed to ensure that such dosages are really necessary. Further work needs to be undertaken to find the best approach to poor treatment adherence and false claims for financial support. The benefits of particular components of specialist assessment need to be evaluated prospectively and multicentre collaboration is needed to evaluate phenotype specific treatment and new treatments for truly difficult asthma.