Purpose of the Study. Seventy-five percent of the asthma care in the United States is provided by primary care generalists. The National Asthma Education and Prevention Program guidelines recommend spirometry to assess management once the peak flow has stabilized. The purpose of this study was to assess how pulmonary-function tests (PFTs) performed during a patient encounter influence management decisions beyond the history and physical examination alone.
Study Population. A total of 367 asthmatic patients were enrolled during their visit to a pediatric pulmonary clinic. The patients were 4 to 18 years old (mean: 10.4 years), and 60% were male. Patients were excluded if PFTs could not be performed on them, if they had a pulmonary diagnosis other than asthma, or if they had used albuterol within 4 hours.
Methods. History of asthma symptoms was obtained, and a physical examination was performed. Spirometry was performed before the provider assessment. Peak expiratory flow rate (PEF) was also obtained. The results of the PFTs were not known to the provider at the time of the assessment and initial decision-making. The provider then reviewed the spirometry results and revised the initial recommendations if necessary. Changes in management were analyzed with respect to demographic data and spirometry. The diagnostic accuracy of PEF to detect abnormal lung function was determined.
Results. Eight percent of the patients had mild intermittent asthma, 21% mild persistent asthma, 57% moderate persistent asthma, and 14% severe persistent asthma. Spirometry results were normal in 55% of the visits. Abnormal spirometry occurred equally in boys and girls. Sixty percent of the abnormal results were new compared with previous baseline measurements. The likelihood of an abnormal PFT increased with increasing severity classification. Ten percent of those in the group with mild intermittent asthma had abnormal PFTs, compared with 74% of those with severe persistent asthma. PFT results changed management in 15% of the visits. When spirometry did not change the treatment, the providers were more likely to have already decided to maintain therapy (58%). When spirometry did change treatment, providers were more likely to increase medications (75%). PEF was moderately inaccurate in detecting abnormal spirometry.
Conclusions. In a clinical setting, even asthma care experts tended to overestimate the degree of asthma control as measured by airway obstruction. Spirometry results in this study were just as likely to be abnormal in patients with a normal history and physical examination.
Reviewer Comments. The next logical question is: Does decision-making enhanced by spirometry result in better outcomes such as decreased symptoms, improved functioning and sleep, fewer exacerbations requiring steroid rescue, and less use of urgent asthma care services? When assessing asthma control, one should always consider comorbidities and adherence issues before stepping up therapy.
- Copyright © 2006 by the American Academy of Pediatrics