The asthma guidelines published by the Global Initiative for Asthma Control (GINA) committee have been recognized by colleagues worldwide for keeping track of new developments in the field of global asthma research.
In 2014, the GINA committee revised its guidelines again, covering asthma definition, phenotype, diagnosis, graded treatment and management, etc. In the updated 2015 GINA guidelines, the latest research findings from the past year have been added.
Professor Liu Chuanhe from the Asthma Prevention and Education Center of the Capital Institute of Pediatrics first interpreted the 2015 GINA guidelines regarding the diagnosis and management of bronchial asthma in children to demonstrate new perspectives on asthma prevention and treatment in recent years.
1.Definition of asthma
When asthma was defined in the previous GINA guidelines and our guidelines, it was considered that asthma is a chronic inflammatory disease of the respiratory tract involving a variety of cells and cytokines. This chronic inflammation leads to increased respiratory reactivity, and under the action of various trigger factors, patients clinically present with recurrent episodes of wheezing, cough, chest tightness and dyspnea.
The current GINA guidelines first mention asthma as a heterogeneous disease usually characterized by chronic inflammation of the respiratory tract with respiratory symptoms such as wheezing, shortness of breath, chest tightness and cough, which and their degree vary over time and are accompanied by varying degrees of expiratory airflow restriction. It can be seen that the definition of asthma in the new GINA guidelines is still based on the pathophysiological and clinical features of asthma in the original definition, i.e. chronic inflammation of the airways, recurrent respiratory symptoms and reversible airflow limitation, while emphasizing the complexity and diversity of the pathogenesis and clinical manifestations of asthma.
2.Clinical classification of asthma
The 2008 PRACTALL Consensus Report on Childhood Asthma and the 2011 International Consensus on Childhood Asthma (iCON) addressed the phenotypes of childhood asthma, respectively. The former classified childhood asthma into four phenotypes: viral-induced asthma, exercise-induced asthma, allergen-induced asthma, and undefined asthma, while the latter included multifactorial and obesity phenotypes in addition to the above four phenotypes.
The new GINA guidelines though suggest the following 5 common clinical phenotypes.
(1) allergic asthma: childhood onset with a personal or family history of atopic disease.
(2) Non-allergic asthma: sputum cytology reveals neutrophils, eosinophils or a small number of inflammatory cells.
(3) Late-onset asthma: onset in adulthood, unrelated to allergy.
(4) Fixed airflow limitation asthma: some patients with long duration of disease may develop fixed airflow limitation due to airway remodeling.
(5) Asthma with obesity: some obese patients with asthma have significant respiratory symptoms and mild eosinophilic inflammation of the airways.
However, it should be noted that the above five phenotypes are proposed basically for adult patients. Some of the proposed phenotypes, such as late-onset asthma, do not belong to the category of children. Although state-specific airflow limitation is seen in children, the specific situation in children needs to be explored. Similarly, asthma with obesity is more frequent in children, but the need to present it as a phenotype is still a matter of opinion.
The diagnosis and management of asthma in young children is currently the focus and difficulty of childhood asthma management. The new GINA guidelines do not propose asthma typology for children 5 years and younger, but only wheezing phenotypes, i.e., typology based on clinical symptoms and typology based on disease trends: the former includes intermittent wheezing (often caused by viral infection, with symptoms during the infection period and normal during the non-viral infection period) and multi-factor triggered wheezing (with symptoms during the viral infection period and still with symptoms during the non-viral infection period, often occurring or worsening at night, during activity, crying/laughing). The latter includes transient wheezing (symptoms begin and disappear before 3 years of age), persistent wheezing (symptoms begin before 3 years of age and persist until after 6 years of age), and delayed wheezing (symptoms begin after 3 years of age). Of this typing method, the former has some guidance for clinical diagnosis and management, while the latter comes from retrospective epidemiological studies and is usually considered to be limited to theoretical discussion, difficult to use to guide clinical practice, and lacking in clinical utility.
The diagnosis and differential diagnosis of asthma in older children (6 years of age and older) is based on the same criteria and methods as in adults, i.e., a history of recurrent respiratory symptoms and the confirmed presence of variable expiratory airflow limitation.
Allergy testing and exhaled nitric oxide testing are important adjuncts to the diagnosis of asthma, but they are not definitive.
The diagnosis of asthma in young children (5 years and younger) is based on 3 main aspects.
① symptom characteristics.
② the presence of risk factors for the development of asthma.
③ Response to experimental controlled drug therapy.
In addition, the guidelines recommend that asthma be diagnosed and treatment given in young children based on the duration of the child’s respiratory symptoms at the time of respiratory infection and during the non-infectious period, the frequency and severity of symptoms over 1 year, nocturnal conditions, and atopic or family history of asthma, with reference to the scales given in the guidelines, in order to avoid under- or over-treatment. Tests to confirm the diagnosis of asthma in children aged 5 years and younger are still lacking.
4. Assessment of asthma control
The assessment of asthma control in the new guideline still includes 2 major aspects, namely, current clinical symptom control and future risk assessment, but the importance of risk assessment is highlighted.
The assessment of clinical symptom control also follows the original assessment form.
5. Treatment of asthma
Initial regimen of asthma drug therapy
The graded treatment regimen recommended in the new guidelines basically follows the previous criteria, i.e., mild asthma: use level 1 or 2 treatment regimen; moderate asthma: use level 3 treatment regimen; severe asthma: need for level 4 or 5 treatment regimen.
Note: a: not recommended for children aged 6 to 11 years; ICS: inhaled glucocorticoid; LABA: long-acting B2 receptor agonist; LTRA: leukotriene receptor antagonist; SABA: short-acting p2 receptor agonist; OCS: oral hormone
Note: ICS: inhaled human glucocorticoid; LTRA: leukotriene receptor antagonist; SABA: short-acting B2 receptor agonist ICS.
However, some new points were also made.
(1) The treatment of asthma in patients over 6 years of age may consider the use of low-dose inhaled glucocorticoids (ICS) as an alternative to short-acting B2: receptor agonists (SABA) in addition to short-acting B2: receptor agonists (SABA) as needed in level l treatment regimens.
(2) ICS/formoterol may be used as a palliative agent in addition to SABA in level 3 and higher treatment regimens. The guidelines conclude that in high-risk patients, ICS/formoterol as maintenance and remission therapy significantly reduces acute exacerbations and achieves similar levels of asthma control at lower doses of hormone compared with fixed-dose ICS + long-acting B2:agonist (LABA) or high-dose ICS maintenance therapy plus SABA control on demand.
The tiered treatment regimen for asthma in children under 5 years of age inherited the 2009 GINA Committee guidelines for the diagnosis and management of asthma in children 5 years of age and younger, and was divided into only 4 tiers compared with the treatment regimen for asthma in older children, and its dosing regimen was simpler, with long-term control medications including only ICS and leukotriene receptor antagonists (LTRA), with no LABA or theophylline recommended (Table Table 3). In addition, the guidelines highlighted the place of ICS in the long-term control treatment of asthma by making ICS the preferred control agent in all levels of treatment, regardless of the treatment regimen for older children or for younger children.
Escalation and downgrading of asthma treatment in stepwise treatment regimens, the new guidelines place greater emphasis on escalation or downgrading of asthma for the purpose of controlling symptoms and reducing the risk of future exacerbations, and classify escalation into 3 different conditions.
(1) Continuous escalation (at least 2 to 3 months): escalation therapy is maintained for 2 to 3 months for reassessment and additional therapeutic agents are considered for those who are ineffective.
(2) Short-term escalation (1 to 2 weeks): short-term increase in hormone dose for maintenance therapy, for wheezing episodes due to viral infection or seasonal allergen exposure.
(3) Daily adjustment: for those using budesonide formoterol or beclomethasone dipropionate/formoterol as control and relief medication, temporary dose increases based on symptoms are used as relief medication on top of daily maintenance therapy.
There are few studies on step-down therapy in children with asthma, and guidelines recommend that step-down therapy be considered when asthma symptoms are well controlled and lung function is stable for 3 months; that step-down not be given when the child is at risk of acute exacerbation or fixed airflow limitation and cannot be closely monitored; that the timing of step-down therapy be appropriate (absence of respiratory infection, not during travel); and that step-down therapy be given as an experimental treatment. It is advisable to document the child’s asthma control to ensure that the child has enough medication to return to the previous dose in case of recurrence, and to conduct regular follow-up; for most children, it is appropriate to reduce the ICS dose by 25% to 50% every 3 months. For children who have been asymptomatic for the past 6 to 12 months and do not have any risk factors for seizures, discontinuation of control medication may be considered, but should be monitored closely.