The prevalence of severe refractory asthma.

BACKGROUND: Severe asthma is characterized by difficulty to achieve disease control despite high-intensity treatment. However, prevalence figures of severe asthma are lacking, whereas longstanding estimates vary between 5% and 10% of all asthmatic patients. Knowing the exact prevalence of severe refractory asthma as opposed to difficult-to-control asthma is important for clinical decision making, drug development, and reimbursement policies by health authorities. OBJECTIVE: We sought to estimate the prevalence of severe refractory asthma as defined by the Innovative Medicine Initiative consensus. METHODS: Adult patients with a prescription for high-intensity treatment (high-dose inhaled corticosteroids and long-acting ß2-agonists or medium- to high-dose inhaled corticosteroids combined with oral corticosteroids and long-acting ß2-agonists) were extracted from 65 Dutch pharmacy databases, representing 3% of the population (500,500 inhabitants). Questionnaires were sent to 5,002 patients, of which 2,312 were analyzed. The diagnosis of asthma and degree of asthma control were derived from questionnaires to identify patients with difficult-to-control asthma. Inhalation technique was assessed in a random sample of 60 adherent patients (prescription filling, ≥80%). Patients with difficult-to-control asthma, adherence to treatment, and a correct inhalation technique were qualified as having severe refractory asthma. Results were mirrored to the Dutch population. RESULTS: Of asthmatic adults, 3.6% (95% CI, 3.0% to 4.1%) qualified for a diagnosis of severe refractory asthma, representing 10.4 patients per 10,000 inhabitants. CONCLUSION: The prevalence of severe refractory asthma might be lower than estimated by expert opinion. This implies that currently recognized severe asthma subphenotypes could meet the criteria of rare diseases.

Polarization-sensitive optical coherence tomography in end-stage lung diseases: an ex vivo pilot study.

A non-invasive diagnostic tool to assess remodeling of the lung airways caused by disease is currently missing in the clinic. Measuring key features such as airway smooth muscle (ASM) thickness would increase the ability to improve diagnosis and enable treatment evaluation. In this research, polarization-sensitive optical coherence tomography (PS-OCT) has been used to image a total of 24 airways from two healthy lungs and four end-stage diseased lungs ex vivo, including fibrotic sarcoidosis, chronic obstructive pulmonary disease (COPD), fibrotic hypersensitivity pneumonitis, and cystic fibrosis. In the diseased lungs, except COPD, the amount of measured airway smooth muscle was increased. In COPD, airway smooth muscle could not be distinguished from surrounding collagen. COPD lungs showed increased alveolar size. 3D pullbacks in the same lumen provided reproducible assessment of airway smooth muscle (ASM). Image features such as thickened ASM and size/presence of alveoli were recognized in histology. The results of this study are preliminary and must be confirmed with further ex vivo and in vivo studies. PS-OCT is applicable for in vivo assessment of peribronchial and peribronchiolar lung structures and may become a valuable tool for diagnosis in pulmonology.

Comorbidities in Difficult-to-Control Asthma.

BACKGROUND: Difficult-to-control asthma is associated with significant medical and financial burden. Comorbidities are known to contribute to uncontrolled asthma. Better insight into the prevalence, nature, and risk factors of comorbidities may optimize treatment strategies in patients with difficult-to-control asthma and decrease disease burden. OBJECTIVES: The objectives of this study were to assess the prevalence, number, and type of comorbidities in difficult-to-control asthma compared with not-difficult-to-control asthma, and to investigate whether specific patient characteristics are associated with particular comorbidities. METHODS: A total of 5,002 adult patients with a prescription for high-dose (>1,000 µg) fluticasone or oral corticosteroids, extracted from 65 Dutch pharmacy databases, were sent questionnaires about patient characteristics. Of the 2,312 patients who returned the questionnaires, 914 were diagnosed with difficult-to-control asthma. Diagnoses of comorbidities (gastroesophageal reflux, nasal polyps, cardiovascular disease, anxiety/depression, obesity, and diabetes) were based on treatment prescriptions or questionnaires. Associations were assessed using multivariable logistic regression analyses. RESULTS: A total of 92% of patients with difficult-to-control asthma had ≥1 comorbidity. Patients with difficult-to-control asthma had more comorbidities (mean ± SD comorbidities 2.22 ± 1.27 vs 1.69 ± 1.32; P < .01), and a significantly higher prevalence of each comorbidity, compared with patients with not-difficult-to-control asthma, except for diabetes and nasal polyposis. Comorbidities were associated with specific patient characteristics, including older age, female gender, smoking history, and chronic prednisone use. CONCLUSIONS: Almost all patients with difficult-to-control asthma have comorbidities, in particular asthmatic women of older age, former smokers, and asthmatics who are prednisone dependent. Recognition of these typical characteristics can help physicians in the diagnostic workup, so that adequate preventive measures can be taken.

Severe refractory asthma: an update.

Asthma is a heterogeneous disease in which adequate asthma control cannot be achieved in a substantial proportion despite currently available treatment possibilities. This subgroup has been defined as "severe refractory" asthma. Over the past years considerable progress has been made regarding a more exact definition of severe refractory asthma. A systematic approach to evaluate the asthma patient has been postulated. Further detailed classification into distinct phenotypes is ongoing to target the right treatment to the right patient. And, new therapeutic targeted treatment options are currently in development to provide possible new targets to improve disease state, symptoms and quality of life. This review will provide an update on the latest advancements with regard to all these domains.