Managing Asthma in Primary Care: Putting New Guideline Recommendations Into Context
2009; Elsevier BV; Volume: 84; Issue: 8 Linguagem: Inglês
10.4065/84.8.707
ISSN1942-5546
Autores Tópico(s)Chronic Obstructive Pulmonary Disease (COPD) Research
ResumoMany patients with asthma are treated in the primary care setting. The primary care physician is therefore in a key position to recognize poorly controlled asthma and to improve asthma management for these patients. However, current evidence continues to show that, for a substantial number of patients, asthma control is inadequate for a wide variety of reasons, both physician-related and patient-related. The most recently updated treatment guidelines from the National Asthma Education and Prevention Program were designed to help clinicians, including primary care physicians, manage asthma more effectively with an increased focus on achieving and maintaining good asthma control over time. The current review is intended to assist primary care physicians in improving asthma control among their patients; this review clarifies the new guidelines and provides a specialist's perspective on diagnosis, appropriate therapy, disease control surveillance, and appropriate referral when necessary. This discussion is based primarily on the new guidelines and the references cited therein, supplemented by the author's own clinical experience. Many patients with asthma are treated in the primary care setting. The primary care physician is therefore in a key position to recognize poorly controlled asthma and to improve asthma management for these patients. However, current evidence continues to show that, for a substantial number of patients, asthma control is inadequate for a wide variety of reasons, both physician-related and patient-related. The most recently updated treatment guidelines from the National Asthma Education and Prevention Program were designed to help clinicians, including primary care physicians, manage asthma more effectively with an increased focus on achieving and maintaining good asthma control over time. The current review is intended to assist primary care physicians in improving asthma control among their patients; this review clarifies the new guidelines and provides a specialist's perspective on diagnosis, appropriate therapy, disease control surveillance, and appropriate referral when necessary. This discussion is based primarily on the new guidelines and the references cited therein, supplemented by the author's own clinical experience. Primary care physicians treat a considerable number of patients with asthma. These physicians are well-positioned to recognize inadequately controlled asthma and to improve disease management for many patients with asthma. However, evidence continues to show that, for a substantial number of patients, asthma control is inadequate.1Chapman KR Boulet LP Rea RM Franssen E Suboptimal asthma control: prevalence, detection and consequences in general practice.Eur Respir J. 2008; 31 (Epub 2007 Oct 24.): 320-325Crossref PubMed Scopus (270) Google Scholar, 2Rabe KF Adachi M Lai CK et al.Worldwide severity and control of asthma in children and adults: the global asthma insights and reality surveys.J Allergy Clin Immunol. 2004; 114: 40-47Abstract Full Text Full Text PDF PubMed Scopus (791) Google Scholar, 3Stempel DA McLaughin TP Stanford RH Fuhlbrigge AL Patterns of asthma control: a 3-year analysis of patient claims.J Allergy Clin Immunol. 2005; 115: 935-939Abstract Full Text Full Text PDF PubMed Scopus (68) Google Scholar, 4Sapra SJ Broder MS Chang E Alignment with the revised NHLBI 2007 asthma guidelines, Expert Panel Report 3 (EPR 3) in a large payer database.J Allergy Clin Immunol. 2009; 123: S117Abstract Full Text Full Text PDF Google Scholar In a study of US national administrative claims data, nearly three-fourths of patients with asthma (73%; 46,227/63,324) met the criteria for uncontrolled disease at least once during a 3-year period.3Stempel DA McLaughin TP Stanford RH Fuhlbrigge AL Patterns of asthma control: a 3-year analysis of patient claims.J Allergy Clin Immunol. 2005; 115: 935-939Abstract Full Text Full Text PDF PubMed Scopus (68) Google Scholar A wide range of factors, physician-related and patient-related, can contribute to poor asthma control. One aspect of this problem, as revealed by data from patient surveys, is that many patients overestimate their level of disease control, often tolerating substantial asthma symptoms and having low expectations about the degree of control that is possible.5Holgate ST Price D Valovirta E Asthma out of control? A structured review of recent patient surveys.BMC Pulm Med. 2006; 6: S2Crossref PubMed Scopus (68) Google Scholar, 6Horne R Price D Cleland J et al.Can asthma control be improved by understanding the patient's perspective?.BMC Pulm Med. 2007; 7: 8Crossref PubMed Scopus (171) Google Scholar Patients also frequently exhibit poor adherence to prescribed controller medications7Barnes PJ The size of the problem of managing asthma.Respir Med. 2004; 98: S4-S8Abstract Full Text Full Text PDF PubMed Scopus (29) Google Scholar; additional patient-related factors affecting asthma control include self-management abilities, smoking status, inhaler technique, ability to remember doses, access to prescriptions, and costs of medication.6Horne R Price D Cleland J et al.Can asthma control be improved by understanding the patient's perspective?.BMC Pulm Med. 2007; 7: 8Crossref PubMed Scopus (171) Google Scholar Physician practices can also contribute to inadequate asthma control. Physicians have a tendency to underestimate the prevalence of asthma symptoms and to overestimate the degree to which their patients' asthma is controlled1Chapman KR Boulet LP Rea RM Franssen E Suboptimal asthma control: prevalence, detection and consequences in general practice.Eur Respir J. 2008; 31 (Epub 2007 Oct 24.): 320-325Crossref PubMed Scopus (270) Google Scholar, 6Horne R Price D Cleland J et al.Can asthma control be improved by understanding the patient's perspective?.BMC Pulm Med. 2007; 7: 8Crossref PubMed Scopus (171) Google Scholar; therefore, they may not always prescribe adequate controller medication therapy.7Barnes PJ The size of the problem of managing asthma.Respir Med. 2004; 98: S4-S8Abstract Full Text Full Text PDF PubMed Scopus (29) Google Scholar Physicians may also have an inadequate understanding of disease etiology or may not communicate well with patients, and these problems make it difficult to establish a pharmacotherapeutic regimen that the patient is willing and able to follow.5Holgate ST Price D Valovirta E Asthma out of control? A structured review of recent patient surveys.BMC Pulm Med. 2006; 6: S2Crossref PubMed Scopus (68) Google Scholar In light of the complexities inherent in the long-term management of asthma, national and international guidelines have been developed over the years to assist clinicians in caring for their patients. The use of guideline-based treatment strategies has been shown to favorably affect asthma outcomes, but there has also been increasing recognition that previous guidelines were not adequately followed and did not lead to acceptable levels of asthma control.8Ohar JA Asthma treatment guidelines: current recommendations, future goals.P&T Digest. 2005; 2: 23-27Google Scholar In 2007, the National Asthma Education and Prevention Program (NAEPP) issued updated guidelines for the diagnosis and management of asthma (the Expert Panel Report 3 [EPR3]),9US Department of Health and Human Services, National Institutes of Health, National Heart Lung and Blood Institute, National Asthma Education and Prevention Program Expert Panel Report 3: Guidelines for the Diagnosis and Management of Asthma. NIH Publication No. 07-40511-440. US Dept of Health and Human Services, National Institutes of Health, National Heart, Lung, and Blood Institute, Bethesda, MD2007http://www.nhlbi.nih.gov/guidelines/asthma/asthgdln.pdfGoogle Scholar which, among other changes, shifted the focus to ongoing assessment of disease control with the goal of improving the management of asthma over time. The current review is intended to assist primary care physicians in improving their patients' asthma control, in part through an improved understanding of the new guidelines, and to provide a specialist's perspective on diagnosing asthma and prescribing appropriate therapy, monitoring disease control, and providing appropriate and timely referrals. As such, this review is based primarily on the NAEPP guidelines, the references therein, and the author's clinical experience. The NAEPP, initiated by the National Heart, Lung, and Blood Institute in 1989 in response to the worsening asthmaepidemic, issued its first set of asthma management guidelines in 1991. A revised set of guidelines—the Expert Panel Report 2—was published in 1997 and was updated in 2002. These guidelines first introduced the stepwise approach to asthma therapy that is based on a 4-part classification scheme of disease severity (mild intermittent, mild persistent, moderate persistent, or severe persistent). Although this approach is useful, its limitations have been clearly recognized, particularly the need to more clearly address the fluctuating severity of asthma symptoms over time.8Ohar JA Asthma treatment guidelines: current recommendations, future goals.P&T Digest. 2005; 2: 23-27Google Scholar, 10Long AA Addressing unmet needs in asthma care.P&T Digest. 2005; 2: 16-22Google Scholar, 11Schatz M Pharmacotherapy of asthma: what do the 2007 NAEPP guidelines say?.Allergy Asthma Proc. 2007; 28: 628-633Crossref PubMed Scopus (2) Google Scholar Thus, the EPR3 guidelines, published in 2007, were based on the overall stepwise treatment model but incorporated some fundamental changes. A key modification in the EPR3 guidelines is the emphasis on distinguishing between asthma severity, which is intrinsic to the disease process, and a patient's level of asthma control, which fluctuates over time. Classifying disease severity is the first step in initiating therapy for a patient who has not been taking long-term control medication. Once therapy is initiated, the emphasis shifts to the assessment of asthma control, which will guide decisions about maintaining or adjusting therapy and evaluating the patient's responsiveness to various asthma medications.9US Department of Health and Human Services, National Institutes of Health, National Heart Lung and Blood Institute, National Asthma Education and Prevention Program Expert Panel Report 3: Guidelines for the Diagnosis and Management of Asthma. NIH Publication No. 07-40511-440. US Dept of Health and Human Services, National Institutes of Health, National Heart, Lung, and Blood Institute, Bethesda, MD2007http://www.nhlbi.nih.gov/guidelines/asthma/asthgdln.pdfGoogle Scholar The new guidelines also added a distinction between the domains of current impairment and future risk, which are to be noted by the physician during the assessment of both asthma severity and disease control, so that asthma's effects on quality of life and functional capacity in the present and its risks for the future are considered separately.9US Department of Health and Human Services, National Institutes of Health, National Heart Lung and Blood Institute, National Asthma Education and Prevention Program Expert Panel Report 3: Guidelines for the Diagnosis and Management of Asthma. NIH Publication No. 07-40511-440. US Dept of Health and Human Services, National Institutes of Health, National Heart, Lung, and Blood Institute, Bethesda, MD2007http://www.nhlbi.nih.gov/guidelines/asthma/asthgdln.pdfGoogle Scholar Regarding medication management, the most substantive changes in the EPR3 guidelines are the separate recommendations for 3 age groups of patients (children aged birth to 4 years, children aged 5 to 11 years, or patients aged 12 years or older) and the expansion of treatment steps from 4 to 6 so that the action within each step can be simplified.9US Department of Health and Human Services, National Institutes of Health, National Heart Lung and Blood Institute, National Asthma Education and Prevention Program Expert Panel Report 3: Guidelines for the Diagnosis and Management of Asthma. NIH Publication No. 07-40511-440. US Dept of Health and Human Services, National Institutes of Health, National Heart, Lung, and Blood Institute, Bethesda, MD2007http://www.nhlbi.nih.gov/guidelines/asthma/asthgdln.pdfGoogle Scholar, 11Schatz M Pharmacotherapy of asthma: what do the 2007 NAEPP guidelines say?.Allergy Asthma Proc. 2007; 28: 628-633Crossref PubMed Scopus (2) Google Scholar, 12Kelly HW Rationale for the major changes in the pharmacotherapy section of the National Asthma Education and Prevention Program guidelines.J Allergy Clin Immunol. 2007; 120: 989-994Abstract Full Text Full Text PDF PubMed Scopus (22) Google Scholar In terms of specific medications, the important role of inhaled corticosteroids (ICSs) in asthma therapy continues to be supported. On the basis of new safety data for long-acting β-agonists (LABAs), guidelines recommend equal consideration for either increasing the ICS dose to a medium dose or adding a LABA to low-dose ICS therapy for patients aged 12 years or older whose asthma is inadequately controlled by low-dose ICS therapy. LABAs should not be used as monotherapy. Finally, the use of allergy immunotherapy has been included in steps 2 through 4 for patients aged 5 years or older, and omalizumab has been included for consideration in therapy steps 5 and 6 for patients aged 12 years or older.9US Department of Health and Human Services, National Institutes of Health, National Heart Lung and Blood Institute, National Asthma Education and Prevention Program Expert Panel Report 3: Guidelines for the Diagnosis and Management of Asthma. NIH Publication No. 07-40511-440. US Dept of Health and Human Services, National Institutes of Health, National Heart, Lung, and Blood Institute, Bethesda, MD2007http://www.nhlbi.nih.gov/guidelines/asthma/asthgdln.pdfGoogle Scholar Correctly diagnosing asthma is the first step toward attaining disease control. In general, a diagnosis of asthma is established if episodic symptoms of airflow obstruction or airway hyperresponsiveness are present, airflow obstruction is at least partially reversible, and alternative diagnoses are excluded. The guidelines recommend the use of a detailed medical history, the results of a physical examination (focusing on the upper respiratory tract, chest, and skin), and the results of spirometry (for patients aged 5 years or older) in making the diagnosis. Any additional studies necessary for excluding alternative diagnoses or identifying other potential causes of symptoms should also be performed (eg, chest radiography, specific blood tests).9US Department of Health and Human Services, National Institutes of Health, National Heart Lung and Blood Institute, National Asthma Education and Prevention Program Expert Panel Report 3: Guidelines for the Diagnosis and Management of Asthma. NIH Publication No. 07-40511-440. US Dept of Health and Human Services, National Institutes of Health, National Heart, Lung, and Blood Institute, Bethesda, MD2007http://www.nhlbi.nih.gov/guidelines/asthma/asthgdln.pdfGoogle Scholar However, primary care physicians may choose to refer patients to a specialist for spirometry or other testing. Table 1 lists some key indicators of a diagnosis of asthma, including wheezing; a history of recurrent cough, wheezing, difficulty in breathing, or chest tightness; and symptoms that occur or worsen in the presence of specific triggers.9US Department of Health and Human Services, National Institutes of Health, National Heart Lung and Blood Institute, National Asthma Education and Prevention Program Expert Panel Report 3: Guidelines for the Diagnosis and Management of Asthma. NIH Publication No. 07-40511-440. US Dept of Health and Human Services, National Institutes of Health, National Heart, Lung, and Blood Institute, Bethesda, MD2007http://www.nhlbi.nih.gov/guidelines/asthma/asthgdln.pdfGoogle Scholar Particularly important factors that should be addressed as part of the medical history include the overall pattern of symptoms (eg, perennial, seasonal, or both; continual, episodic, or both; diurnal variations), precipitating factors (such as the presence of allergic triggers), and a family history of asthma, allergy, or other atopic disorders.9US Department of Health and Human Services, National Institutes of Health, National Heart Lung and Blood Institute, National Asthma Education and Prevention Program Expert Panel Report 3: Guidelines for the Diagnosis and Management of Asthma. NIH Publication No. 07-40511-440. US Dept of Health and Human Services, National Institutes of Health, National Heart, Lung, and Blood Institute, Bethesda, MD2007http://www.nhlbi.nih.gov/guidelines/asthma/asthgdln.pdfGoogle ScholarTABLE 1Key Indicators for Considering a Diagnosis of AsthmaaConsider a diagnosis of asthma and performing spirometry if any of these indicators is present. These indicators are not diagnostic in themselves, but the presence of multiple key indicators increases the probability of a diagnosis of asthma. Spirometry is needed to establish a diagnosis of asthma. Eczema, hay fever, and a family history of asthma or atopic diseases are often associated with asthma, but they are not key indicators.From Expert Panel Report 3: Guidelines for the Diagnosis and Management of Asthma.9US Department of Health and Human Services, National Institutes of Health, National Heart Lung and Blood Institute, National Asthma Education and Prevention Program Expert Panel Report 3: Guidelines for the Diagnosis and Management of Asthma. NIH Publication No. 07-40511-440. US Dept of Health and Human Services, National Institutes of Health, National Heart, Lung, and Blood Institute, Bethesda, MD2007http://www.nhlbi.nih.gov/guidelines/asthma/asthgdln.pdfGoogle Scholar Wheezing High-pitched whistling sounds when breathing out, especially in children. (Lack of wheezing and normal findings on chest examination do not exclude asthma.)History of any of the following Cough, worse particularly at nightRecurrent wheezeRecurrent difficulty in breathingRecurrent chest tightnessSymptoms occur or worsen in the presence of the following ExerciseViral infectionAnimals with fur or hairHouse-dust mites (in mattresses, pillows, upholstered furniture, carpets)MoldSmoke (tobacco, wood)PollenChanges in weatherStrong emotional expression (laughing or crying hard)Airborne chemicals or dustsMenstrual cyclesSymptoms occur or worsen at night, awakening the patienta Consider a diagnosis of asthma and performing spirometry if any of these indicators is present. These indicators are not diagnostic in themselves, but the presence of multiple key indicators increases the probability of a diagnosis of asthma. Spirometry is needed to establish a diagnosis of asthma. Eczema, hay fever, and a family history of asthma or atopic diseases are often associated with asthma, but they are not key indicators. Open table in a new tab Although recurrent cough and wheezing are often due to asthma, other causes of airway obstruction should be considered in the initial diagnosis or if the patient does not respond to initial therapy. Table 2 lists the most common possibilities included in the differential diagnosis of asthma, according to the EPR3 guidelines. Vocal cord dysfunction—characterized by episodic dyspnea and wheezing caused by intermittent paradoxical vocal cord adduction during inspiration—often mimics asthma and can be difficult to diagnose. A diagnosis is best made with indirect or direct vocal cord visualization during an episode, and treatment generally consists of speech therapy and relaxation techniques.TABLE 2Differential Diagnostic Possibilities for AsthmaFrom Expert Panel Report 3: Guidelines for the Diagnosis and Management of Asthma.9US Department of Health and Human Services, National Institutes of Health, National Heart Lung and Blood Institute, National Asthma Education and Prevention Program Expert Panel Report 3: Guidelines for the Diagnosis and Management of Asthma. NIH Publication No. 07-40511-440. US Dept of Health and Human Services, National Institutes of Health, National Heart, Lung, and Blood Institute, Bethesda, MD2007http://www.nhlbi.nih.gov/guidelines/asthma/asthgdln.pdfGoogle Scholar Infants and children Upper airway diseases Allergic rhinitis and sinusitisObstructions involving large airways Foreign body in trachea or bronchusVocal cord dysfunctionVascular rings or laryngeal websLaryngotracheomalacia, tracheal stenosis, or bronchostenosisEnlarged lymph nodes or tumorObstructions involving small airways Viral bronchiolitis or obliterative bronchiolitisCystic fibrosisBronchopulmonary dysplasiaHeart diseaseOther causes Recurrent cough not due to asthmaAspiration due to dysfunction of the swallowing mechanism or to gastroesophageal reflux Adults Chronic obstructive pulmonary disease (eg, chronic bronchitis or emphysema)Congestive heart failurePulmonary embolismMechanical obstruction of the airways (benign and malignant tumors)Pulmonary infiltration with eosinophiliaCough resulting from administration of drugs (eg, angiotensin-converting enzyme inhibitors)Vocal cord dysfunction Open table in a new tab Several other conditions may coexist with asthma or complicate the diagnosis or management of asthma. Cough-variant asthma, in particular, is easily overlooked because chronic cough can be a sign of a wide variety of health problems. Conversely, chronic cough may also be the principal (or only) manifestation of asthma, especially among young children. The diagnosis of cough-variant asthma is confirmed by a positive response to asthma medication, and treatment should follow the usual stepwise approach to asthma management. Other common comorbid conditions that complicate the diagnosis of asthma are chronic sinusitis, gastroesophageal reflux disease, obstructive sleep apnea, and respiratory tract infections. Because it is often accompanied by symptoms similar to those of asthma and by elevated IgE levels, allergic bronchopulmonary aspergillosis should also be excluded.9US Department of Health and Human Services, National Institutes of Health, National Heart Lung and Blood Institute, National Asthma Education and Prevention Program Expert Panel Report 3: Guidelines for the Diagnosis and Management of Asthma. NIH Publication No. 07-40511-440. US Dept of Health and Human Services, National Institutes of Health, National Heart, Lung, and Blood Institute, Bethesda, MD2007http://www.nhlbi.nih.gov/guidelines/asthma/asthgdln.pdfGoogle Scholar, 13Berlow BA Eight key questions to ask when your patient with asthma doesn't get better.Am Fam Physician. 1997; 55 (192-194): 183-189PubMed Google Scholar Although rare, Churg-Strauss syndrome is another comorbid condition that should be considered in the assessment of patients with difficult-to-control asthma. It is a serious disorder characterized by eosinophilic inflammation of the respiratory tract and necrotizing vasculitis of small and medium vessels. Laboratory results demonstrate eosinophilia, and symptoms include asthma, rhinosinusitis, pulmonary infiltrates, peripheral neuropathy, and skin, heart, or gastrointestinal involvement.14Lilly CM Churg A Lazarovich M et al.Asthma therapies and Churg-Strauss syndrome.J Allergy Clin Immunol. 2002; 109: S1-S19Abstract Full Text Full Text PDF PubMed Scopus (67) Google Scholar Once the diagnosis of asthma has been established, the focus shifts to classifying asthma severity so that therapy can be initiated and to monitoring control over time so that therapy can be adjusted. According to the new guidelines, severity and control should be assessed separately, but both are classified on the basis of the domains of current impairment and future risk. Impairment is defined as "the frequency and intensity of symptoms and functional limitations the patient is experiencing currently or has recently experienced," whereas risk is defined as "the likelihood of either asthma exacerbations, progressive decline in lung function (or, for children, lung growth), or risk of adverse effects from medication." The new guidelines stress that the impairment domain and the risk domain may respond differently to treatment.9US Department of Health and Human Services, National Institutes of Health, National Heart Lung and Blood Institute, National Asthma Education and Prevention Program Expert Panel Report 3: Guidelines for the Diagnosis and Management of Asthma. NIH Publication No. 07-40511-440. US Dept of Health and Human Services, National Institutes of Health, National Heart, Lung, and Blood Institute, Bethesda, MD2007http://www.nhlbi.nih.gov/guidelines/asthma/asthgdln.pdfGoogle Scholar In assessing impairment, asthma severity should be evaluated using the categories outlined in Figure 1.9US Department of Health and Human Services, National Institutes of Health, National Heart Lung and Blood Institute, National Asthma Education and Prevention Program Expert Panel Report 3: Guidelines for the Diagnosis and Management of Asthma. NIH Publication No. 07-40511-440. US Dept of Health and Human Services, National Institutes of Health, National Heart, Lung, and Blood Institute, Bethesda, MD2007http://www.nhlbi.nih.gov/guidelines/asthma/asthgdln.pdfGoogle Scholar Severity should be assigned according to the most severe category of impairment. Assessment of future risk, which is based on the frequency of exacerbations requiring the administration of oral systemic corticosteroids, is another important facet of asthma severity. The occurrence of exacerbations can vary widely (from rare to frequent) among patients and for each individual patient. Because patients at any level of disease severity, including intermittent asthma, can experience severe exacerbations, the current version of the guidelines has omitted the word mild from the former classification of mild intermittent asthma. Although the current guidelines state that evidence is insufficient to confirm an association between the frequency of exacerbations and the level of asthma severity, in general, the more frequent and the more intense the exacerbations, the greater the degree of underlying disease severity.9US Department of Health and Human Services, National Institutes of Health, National Heart Lung and Blood Institute, National Asthma Education and Prevention Program Expert Panel Report 3: Guidelines for the Diagnosis and Management of Asthma. NIH Publication No. 07-40511-440. US Dept of Health and Human Services, National Institutes of Health, National Heart, Lung, and Blood Institute, Bethesda, MD2007http://www.nhlbi.nih.gov/guidelines/asthma/asthgdln.pdfGoogle Scholar, 15Fuhlbrigge AL Adams RJ Guilbert TW et al.The burden of asthma in the United States: level and distribution are dependent on interpretation of the national asthma education and prevention program guidelines.Am J Respir Crit Care Med. 2002; 166: 1044-1049Crossref PubMed Scopus (264) Google Scholar One study found that the rates of hospitalizations, urgent care visits, and absenteeism for patients with moderateto severe persistent asthma were 2-fold to 4-fold higher than those for patients with mild intermittent asthma.15Fuhlbrigge AL Adams RJ Guilbert TW et al.The burden of asthma in the United States: level and distribution are dependent on interpretation of the national asthma education and prevention program guidelines.Am J Respir Crit Care Med. 2002; 166: 1044-1049Crossref PubMed Scopus (264) Google Scholar For the purposes of classification, the guidelines specify that patients who have experienced 2 or more exacerbations requiring the administration of oral corticosteroids during the past year are considered to have persistent asthma, even if all of the impairment categories suggest that they have intermittent asthma.9US Department of Health and Human Services, National Institutes of Health, National Heart Lung and Blood Institute, National Asthma Education and Prevention Program Expert Panel Report 3: Guidelines for the Diagnosis and Management of Asthma. NIH Publication No. 07-40511-440. US Dept of Health and Human Services, National Institutes of Health, National Heart, Lung, and Blood Institute, Bethesda, MD2007http://www.nhlbi.nih.gov/guidelines/asthma/asthgdln.pdfGoogle Scholar After disease severity has been assigned, treatment can be initiated at the recommended step. If the patient is already receiving asthma therapy, symptom control should be periodically monitored according to the same domains of impairment and risk (with additional categories for each domain; see What Does Good Asthma Control Look Like?). Assessment of control is used to guide alterations in therapy according to the stepwise approach (also discussed hereinafter). Minimally invasive markers, such as fractionated exhaled nitric oxide (FeNO) levels and sputum eosinophil counts, may also be useful for assessing asthma control, monitoring medication adherence, and adjusting therapy; however, the guidelines suggest that further evaluation of these measures is necessary before they can be considered to be tools for routine management.9US Department of Health and Human Services, National Institutes of Health, National Heart Lung and Blood Institute, National Asthma Education and Prevention Program Expert Panel Report 3: Guidelines for the Diagnosis and Management of Asthma. NIH Publication No. 07-40511-440. US Dept of Health and Human Services, National Institutes of Health, National Heart, Lung, and Blood Institute, Bethesda, MD2007http://www.nhlbi.nih.gov/guidelines/asthma/asthgdln.pdfGoogle Scholar Nevertheless, FeNO has been used for asthma diagnosis, as a rapid response
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