Nevertheless, if we accept that the conclusions are correct, the study suggests that successful follow-up is determined not so much by who performs it than by what is done. First, the diagnosis should be confirmed. In the study Nathan et al, the diagnosis of nearly 10% of patients who were apparently hospitalized for asthma was not confirmed, although the correct diagnoses for those patients are not presented. Second, studies have documented that the following factors, which could be addressed on a follow-up appointment, are related to an increased risk of asthma-related emergency department visits or hospitalizations: inadequate asthma knowledge; not having an action plan; incorrect use of me-tered-dose inhalers; adverse environmental exposures, especially regarding environmental tobacco smoke and mites’; and adverse psychosocial circumstances.
Finally, a 2004 metaanalysis has confirmed that therapy with inhaled steroids, long-acting (3-agonists, and leukotriene modifiers reduces the number of asthma exacerbations, with inhaled steroids being most effective agent used in that regard. The successful nurse-led intervention by Castro et al appeared to address most of the factors listed above as well as to facilitate necessary ongoing follow-up. Many of these factors also appear to have been addressed in the study by Nathan et al, in which “the consultation in either arm of the study consisted of an evaluation of the events leading to the hospital admission, an assessment of the patients’ understanding of their asthma, initiation or reinforcement of asthma education, an assessment of their understanding of asthma therapy, assessment of inhaled technique, a self management plan and appropriate change in asthma medication.”
One important question raised by the study of Nathan et al is why 47% of the patients who were seen by the respiratory nurses or physicians still experienced exacerbations during the 6 months of follow-up, including 10% who required rehospitalization. In addition to inadequate pharmacologic therapy and education regarding trigger avoidance or self-management, we suspect that poor patient adherence to treatment, psychosocial factors, and inherent asthma severity are likely explanations. Most of these factors could presumably be addressed by more effective interventions by both nurses and physicians, although specific recommendations cannot be made from the available information.
In conclusion, specialist care after an asthma hospitalization can improve outcomes, and a specially trained respiratory nurse practitioner may do just as well as a respiratory physician in this regard. However, further studies in larger populations of patients will be necessary to confirm these conclusions. Further studies also are needed to address larger issues, such as what aspects of follow-up care actually result in improved outcomes and what additional interventions are necessary for those whose outcomes are not improved despite asthma specialist care.