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CLASSIFYING ASTHMA SEVERITY AND TREATMENT DETERMINANTS: NATIONAL GUIDELINES REVISITED 

R Khajotia MBBS (Bom), MD (Bom), MD (Vienna), FAMA (Vienna), FAMS (Vienna). International Medical University, Seremban, Malaysia

Address for correspondence: Dr. Rumi Khajotia, Associate Professor in Internal Medicine and Pulmonology,
International Medical University Clinical School, Seremban, Malaysia. Tel: 606-7677798 ext 190. Email:  rumi@imu.edu.my

INTRODUCTION

Asthma is an inflammatory disease of the airways associated with intermittent episodes of bronchospasm.1 Bronchodilators effectively relieve the bronchospasm and consequent symptoms but do not treat the underlying airway inflammation which is the mainstay in an underlying asthmatic attack. At present, corticosteroids are the most effective anti-inflammatory agents available for the treatment of bronchial asthma.

When given at low doses in the inhaled form, corticosteroids act as topical anti-inflammatory agents in the bronchial passages with minor risk of any significant systemic exposure.² Inhaled corticosteroids have been shown to have effectively reduced airway inflammation,³ control asthma symptoms, decrease the frequency and severity of acute exacerbations, improve lung functions, reduce frequency of hospitalization⁴ and consequently reduce both morbidity and mortality rates.⁵ However, as higher doses of inhaled corticosteroids are used, the risks of systemic side effects have been known to increase.⁶

It has been observed that beneficial effects from higher doses of inhaled corticosteroids are significantly less than previously thought. One study indicated that maximal symptomatic and lung function improvements were found at low- to medium doses of inhaled fluticasone propionate.⁷ Similar results were obtained while comparing increasing doses of inhaled fluticasone propionate and beclomethasone dipropionate.⁸ Also, doubling the dose of inhaled corticosteroids during clinical deterioration does little to prevent an acute exacerbation.⁹

It has been observed that only those patients who are chronic asthmatics, resistant to most conventional therapies including oral and inhaled beta-agonists and who require chronically high doses of oral corticosteroids stand to benefit from very high doses of 

inhaled corticosteroids.^10,11 Also, systemic risks of long-term inhaled corticosteroids are substantially less than previously thought. Though inhaled corticosteroids are known to suppress the hypothalamic-pituitary-adrenal axis, it is rarely ever the cause of clinically perceived adrenal insufficiency.¹² Inhaled corticosteroids are also known to transiently decrease the growth velocity in prepubertal children. But this does not result in the diminution of the actual height attained.¹³ Skin bruising is known to occur with long-term use of inhaled corticosteroids.¹⁴ This occurs more commonly in the elderly and is primarily a cosmetic problem.

However, it needs to be remembered that long-term use of high doses of inhaled corticosteroids are associated with side effects such as osteopenia, myopathy, cataracts, growth retardation and Cushing’s syndrome.^15,16

Hence it can be surmised that the benefit-to-risk profile of inhaled corticosteroids is clearly favourable at low-to-medium doses wherein considerable benefit is obtained with little risk of adverse systemic side effects. However, use of high doses of inhaled corticosteroids entails the risk of systemic side effects. Hence, the use of higher doses should be restricted to those carefully chosen clinical conditions in which the anticipated benefits can be justified. This can only be determined if patients with more severe asthma can be reliably identified.

Therefore, it is vitally important to categorize the severity of asthma attacks so that appropriate treatment modalities can be adopted.

CLASSIFYING ASTHMA SEVERITY

Classifying the severity of asthmatic attacks based on clinical features and convenient parameters such as peak flow rates, is believed to be an invaluable method in the management of bronchial asthma. Several methods for categorizing asthma severity have been devised in the United States of America, the United Kingdom, Australia and Canada and are routinely being used to follow and manage patients with bronchial asthma. 

NAEPP Classification

The most widely accepted classification of asthma severity was that recommended by the National Heart, Lung and Blood Institute’s (NHLBI) National Asthma Education and Prevention Program (NAEPP) Expert Panel Report 2. These guidelines placed major emphasis on diagnosis ( including classification of asthma) and management, which included a stepped approach to asthma treatment. The NAEPP classification relies on an assessment of asthma symptoms and lung function at the time the patient is being evaluated and prior to commencement of treatment. Three variables are considered in classifying asthma severity, namely, daytime symptoms, nighttime symptoms, and lung function. Abnormalities within each of these three variables are graded into four separate categories of severity. Overall asthma severity is categorized according to the worst individual variable. For example, if a patient has severe persistent daytime symptoms (placing him in the severe persistent category for this variable) but has nighttime symptoms less than twice per week and normal lung function (both in mild, intermittent category), the overall asthma categorization would be severe, persistent.

Recently, EPR 3 guidelines have been released which are essentially based on the 1997 EPR 2 guidelines as the framework. These guidelines are now organised around four essential components of asthma care, namely: assessment and monitoring, patient education, control of factors contributing to asthma severity and pharmacologic treatment.¹⁷

Table 1. NAEPP classification of asthma severity

Symptoms: Cough, Shortness of Breath, Wheezing or Chest Tightness.

Patients should be assigned to the most severe step in which ANY feature occurs:

Symptoms Severity	Days with Symptoms	Nights with Symptoms	PEFR FEV1	PEF Variability
Step 4 Severe Persistent	Continual	Frequent	≤ 60 %	> 30 %
Step 3 Moderate Persistent	Daily	> 1/ week	> 60% - < 80 %	< 30 %
Step 2 Mild Persistent	>2/ week, but < 1 / day	> 2 / month	≥ 80 %	20-30%
Step 1 Mild Intermittent	≤ 2 / week	≤ 2 / month	≥ 80 %	< 20 %

Australian National Asthma Campaign Classification

This classification is developed based on the consensus of experts. By this method, asthma severity is assessed while the patient is clinically stable, at the same time taking into consideration a past history of either hospitalization or near-fatal asthma attacks.¹⁸ Like the method established in the Expert Panel Report 2, the worst individual categorization will determine overall asthma severity. An additional consideration to asthma severity categorization is the identification of the “high risk” patient. There is an overlap between variables used to categorize asthma severity and characteristics of the “high risk” patient. However, other factors, such as poor compliance with treatment, denial of asthma as a personal medical problem, history of asthma initiated by aspirin or other non-steroidal anti-inflammatory drugs, and immediate hypersensitivity to foods are termed high-risk characteristics. Identifying a high-risk patient will not necessarily lead to changes in therapy, but does indicate the need for closer follow-up. 

Table 2. Classification of asthma severity: method of Australian National Asthma Campaign¹⁸

Severity	Wheeze, tightness, cough, dyspnoea	Nighttime Symptoms	Symptoms on waking	Admission or emergency visits	Previous life-threatening attack	Short acting ß-agonist use	FEV1	PEF
Severe	Every day	> 1 / week	> 1 / week	Usually	May have a history	>3 to  4 / day	<60%	<80%
Moderate	Most days	< 1 / week	< 1 / week	Usually not	Usually not	Mos days	60% to 80%	80% to 90%
Mild	Occasional	Absent	Absent	Absent	Absent	<2 / week	>80%	>90%

FEV1: forced expiratory volume in one second; PEF: peak expiratory flow rate

The Global Initiative for Asthma Guidelines (GINA)

The Global Initiative for Asthma (GINA) guidelines are the combined efforts of NHLBI and the World Health Organisation (WHO). Although these recommendations are essentially similar to the NAEPP guidelines, there are subtle changes in language, including specific details within the stepped approach to asthma therapy. The guidelines were recently updated in 2008.¹⁹ These latest updates are essentially based on research published and the impact of publications from July 1, 2007 through June 30, 2008. 

Table 3. GINA classification of asthma severity by clinical features before treatment

	Symptoms/Day	Symptoms/Night	PEF or FEV1	PEF variability
STEP 1 Intermittent	< 1 time a week Asymptomatic and normal PEF between attacks	≤ 2 times a month	≥ 80%	< 20%
STEP 2 Mild Persistent	> 1 time a week but < 1 time a day Attacks may affect activity	>2 times a month	≥ 80%	20-30%
STEP 3 Moderate Persistent	Daily Attacks affect activity	> 1 time a week	60%-80%	> 30%
STEP 4 Severe Persistent	Continuous Limited physical activity	Frequent	≤ 60%	> 30%

The presence of one of the features of severity is sufficient to place a patient in that category. Patients at any level of severity, even intermittent asthma, can have severe attacks.