otohns.net Stepped-Care Approach To The Medical Management of Asthma

"STEPPED-CARE APPROACH TO THE MEDICAL MANAGEMENT OF ASTHMA"
John Murray, MD, PhD
otohns.net International Advisory Board
Departments of Medicine and Pharmacology

Asthma is increasing in morbidity and mortality despite a better understanding of the pathogenesis of the disease. Medications are currently available to alter the natural history of asthma and substantially reduce both the economic as well as personal impact of this disease. To attain these goals, the recently published "Guidelines for the Diagnosis and Management of Asthma, Expert Panel Report 2" sponsored by NIH advocates the aggressive treatment of asthma at an early clinical stage. The concept that asthma is simply a disease of reversible airway obstruction is obsolete with the understanding that asthma is a chronic inflammatory disorder of the airway that can result in irreversible changes. This inflammation contributes not only to the bronchoconstriction, but also mucus plugging, and detrimental airway remodeling with evidence that even mild clinical symptoms reflect inflammation that can produce irreversible loss of lung function. Physicians must approach treatment in terms of long-term control rather than treating exacerbations in order to provide optimum care, and the asthmatic should be educated to expect nothing less. The cornerstone of this long-term control is the use of inhaled corticosteroids with quick relief for acute episodes provided by inhaled short-acting beta adrenergic agonists. The proper implementation of a stepped-care approach to treating asthma with these agents in conjunction with alternative and additional therapeutic considerations should contribute to substantial reduction in the morbidity and mortality of this disease.

The basis for the medical approach to the treatment of asthma involves the consideration of two general groupings of therapies. These two categories include medications considered quick relievers and those considered long-term controllers. The former category includes drugs that reverse bronchospasm acutely, while the latter category includes drugs that possess anti-inflammatory properties as well as those that produce long-term bronchodilation as a means of providing long-term control. The relievers include the short acting inhaled beta agonists or alternatively anticholinergic therapy, if the latter is not well tolerated, and acute oral steroids. The controllers include the anti-inflammatory agents - inhaled steroids and the mast cell stabilizers cromolyn and nedocromil, and the long-term bronchodilator controllers - a long acting inhaled beta adrenergic agonist (Serevent) and theophylline. The newly released agents that modify leukotriene participation (Zyflo, Accolate and Singulair) in the asthmatic response appear to have activity to relieve symptoms, but primarily provide long term control and therefore should be considered in the controller category. The stepped care management of the asthmatic is stratified according to the severity of the disease into mild episodic, mild persistent, moderate and severe categories with the use of the various agents advocated at each step.

Mild intermittent asthma is defined as asthma presenting with normal pulmonary functions (i.e., forced vital capacity in one second, FEV1 >80%) and less than 1 episode of asthma a week and no symptoms between episodes. Most of these asthmatics can be managed with the use of an inhaled beta agonist alone for the symptoms or prior to exercise. Inhaled nedocromil or cromolyn can be considered if additional measures to the beta agonist are required prior to antigen exposure (eg, cat) or exercise. Individuals with normal pulmonary function tests but having more than 1 episode of symptoms a week (classified as the mild persistent asthmatic) require the initiation of controller therapy. The medication of choice clearly remains the use of low dose inhaled steroids as these have been shown to prevent progression to irreversible loss of lung function. Alternative controller therapies include the use of inhaled nedocromil or cromolyn, and to a lesser degree a long acting inhaled beta agonist (particularly useful for nocturnal asthma), an oral beta agonist, theophylline or one of the newer anti-leukotriene agents.

For those asthmatics with episodes of asthma more than several times a week and with abnormal pulmonary functions (FEV1 60-80% without treatment, classified as the moderate persistent asthma), the dose of inhaled steroids should be increased to a moderate level, or alternatively a long acting inhaled beta agonist could be added to the low dose of the inhaled steroid. Several studies now appear to demonstrate that the latter approach provides a superior clinical benefit. Alternatively, theophylline or an oral long acting beta agonist could be added to a low dose inhaled steroid. An inhaled short acting beta agonist is used for quick relief of asthma exacerbations. Finally, for those with severe symptoms (daily symptoms with FEV1<60% without treatment, classified as the severe persistent asthma), high dose inhaled steroids are appropriate combined with a long acting inhaled beta agonist, or oral beta agonist or theophylline, with addition of anti-leukotriene modulators or oral steroids if required for additional control of symptoms. Again for quick relief, a short acting inhaled beta agonist is recommended.

The goal of therapy is to prevent irreversible disease from developing secondary to chronic inflammation. This approach will also minimize acute asthma exacerbations which has been the previous mainstay of the ultimate therapeutic goal of asthma treatment. Along with normalization of pulmonary functions, the clinical markers to be followed in terms of controlling the disease are to prevent the necessity or minimize short acting inhaled beta agonist use and nocturnal awakenings. Long-term control of these clinical markers provide a useful guide in terms of titrating medical therapies, either up or down, to not only maintain asthma control but also prevent progression to irreversible changes. If these goals can be met, which should be considered a reasonable aim in nearly all asthmatics, optimum care will be provided.

Conditions such as sinusitis, gastric reflux and immune deficiencies have all been shown to play a role to varying degrees in exacerbating asthma and treatment of these underlying conditions may provide substantial benefit in some asthmatics. As upper respiratory problems frequently precede asthma exacerbations, all steps to minimize this trigger are important. This would include the use of antihistamines or topical steroids for allergic rhinitis and administering the flu shot and/or anti-viral drugs to reduce the likelihood of upper respiratory infections. Treatment of bacterial sinusitis either medically or surgically can have profound beneficial effects on asthma. Immunotherapy in selected individuals may also be very beneficial in controlling asthmatics, particularly those with concomitant upper airway disease. Avoidance of triggers such as inhalants (eg, dust mites, pollens) or food allergens identified by allergy testing, smoke or agents such as aspirin and sulfites are critical for the long-term control of some asthmatics. Finally, and of utmost importance, is the education process of the asthmatic in terms of understanding the nature of their disease and recognizing their disease status (including the use of a peak flow meter), addressing compliance issues, and providing instruction on proper inhaler technique and avoidance of triggers that are all essential for optimal care. As outlined in the new NIH Guidelines, a team approach to develop a close physician-patient relationship will significantly enhance the management of asthma as this is essential for providing optimum care to ensure compliance and the proper implementation of the currently available armamentarium of effective medical treatments for asthma.