The impact of allergy and pulmonary specialist care on emergency asthma utilization in a large managed care organization

Health Services Research, Oct, 2005 by Sara Erickson, Irina Tolstykh, Joe V. Selby, Guillermo Mendoza, Carlos Iribarren, Mark D. Eisner

During the past 20 years, the U.S. morbidity and mortality from asthma have been increasing (Mannino et al. 1998, 2002). In an effort to improve asthma care, the National Asthma Education and Prevention Program (NAEPP) published guidelines for the diagnosis and management of asthma in 1991 (NAEPP 1991). In general, physicians' compliance with these national guidelines appears to be poor (Legorreta et al. 1998; Meng et al. 1999). However, asthma specialists (allergists and pulmonologists) appear to follow the clinical practice guidelines more closely than primary care physicians (Legorreta et al. 1998; Meng et al. 1999; Diette et al. 2001; Frieri et al. 2002). In addition, a substantial body of literature suggests that patients who are managed by asthma specialists have better outcomes than patients managed by primary care physicians (Engel et al. 1989; Mayo, Richman, and Harris 1990; Zeiger et al. 1991; Mahr and Evans 1993; Sperber et al. 1995; Storms et al. 1995; Legorreta et al. 1998; Brunner, Wunsch, and Marmot 2001). These improved outcomes included fewer asthma symptoms, improved quality of life, and fewer emergency department (ED) visits and hospitalizations (Engel et al. 1989; Mayo et al. 1990; Zeiger et al. 1991; Mahr and Evans 1993; Sperber et al. 1995; Storms et al. 1995; Legorreta et al. 1998; Brunner et al. 2001).

On a conceptual basis, asthma specialist care could improve asthma outcomes, including exacerbations and hospitalizations, through a variety of mechanisms. Specialty care might improve identification and remediation of factors that exacerbate asthma, such as workplace exposures to allergens or irritants, dust mites, mold, secondhand tobacco smoke, or comorbid medical conditions (e.g., rhinitis, sinusitis, or gastroesphageal reflux disease). Specialist care could also increase the use of objective assessment and monitoring of asthma using spirometry and peak expiratory flow measurement. Specialists may provide enhanced education about asthma and the use of self-management plans (i.e., "action plans") for handling exacerbations. And specialist visits could result in greater appropriate use of inhaled anti-inflammatory medications and inhaled [beta]-agonists. Some of these putative benefits would be likely to yield short-term improvements, such as inhaled anti-inflammatory medications; other interventions, such as asthma education, would likely result in longer-term behavior change. In both cases, the impacts should be detectable within a period of our study.

Two of the seminal randomized trials of asthma specialist care both facilitated health care access and provided more intense treatment and education to the intervention/specialist group (Mayo et al. 1990; Zeiger et al. 1991). It is therefore difficult to determine which component of the intervention--specialist expertise, improved access to care, or formalized patient education--accounted for the improved outcomes. Notably, all of the studies comparing asthma specialist care to primary care were conducted more than 7 years ago. Since that time, inhaled corticosteroids have become more widely available and additional controller medications have been developed including long-acting [beta]-agonists and leukotriene modifiers. In addition, 12 years have passed since the initial publication of the NAEPP guidelines and since then, two subsequent updates have been released, in 1997 and 2002 (NAEPP 1997, 2002). Many of the studies comparing specialist to generalist care were conducted before the publication of the initial guidelines or shortly thereafter (Engel et al. 1989; Mayo et al. 1990; Zeiger et al. 1991; Sperber et al. 1995; Storms et al. 1995; Mahr and Evans 1993). Now that more time has elapsed, allowing for the dissemination of this important information, outcomes may have improved among patients treated by primary care physicians. Given that two-thirds of patients with asthma receive their care from primary care physicians (Carr, Zeitel, and Weiss 1992) and also given the evolving state of asthma management, a current investigation comparing specialist and generalist asthma care is warranted.

In a prospective cohort study, we evaluated the impact of specialist care on the utilization outcomes of asthma patients enrolled in a large integrated health care delivery system in Northern California. Our study sought to determine whether there was a difference in asthma-related emergency health care utilization among patients treated by asthma specialists (allergists or pulmonologists) compared with primary care physicians. Because this study was conducted within a managed care organization, all study subjects had equal access to health care. In addition, there were system-wide efforts within the organization to improve asthma care by disseminating asthma clinical practice guidelines to all primary care providers. Therefore, we were able to study the effects of asthma specialist care in a health care environment with a high quality of primary care for asthma.