Chest
Volume 113, Issue 2, February 1998, Pages 272-277
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Clinical Investigations: Asthma/Broncho-Dilators
Relationship Between Airway Obstruction and Respiratory Symptoms in Adult Asthmatics

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Study objectives

To characterize the relationship between symptoms and the degree of airway obstruction as determined by the FEV1 and peak expiratory flow (PEF) in a cohort of adult patients attending a university-based urban asthma clinic.

Design

Each of six current asthma symptoms, including cough, dyspnea, wheeze, chest tightness, sputum production, and nocturnal awakening was rated by patients on a 0 (none) to 4 (constant) scale at initial and first follow-up clinic evaluations. Spirometry and PEF were measured at the initial clinic visit and PEF was measured at all follow-up visits.

Patients

Sixty-seven adult patients with chronic asthma.

Measurements and results: Asthma symptoms did not correlate with the degree of airway obstruction as determined by the FEV1 (percent predicted FEV1 vs total symptoms: r=0.143; p=0.263; n=70) and only correlated poorly with PEF (percent predicted PEF vs total symptoms: r=0.384; p=0.0029; n=58). Subjective wheezing was the best individual predictor of the level of airway obstruction in this group of patients. When reassessed an average of 7.9 weeks later, patients reported significant improvement in several symptoms, including those of wheeze, chest tightness, dyspnea, and nocturnal awakening. However, this symptomatic improvement was not associated with improvement in the level of airway obstruction.

Conclusions

Asthma symptoms correlate poorly with the level of airway obstruction as determined by the FEV1 and PEF. Following treatment, subjective improvement in asthma symptoms may occur without improvement in the level of airway obstruction. These results support the recommendation to measure airway obstruction objectively when assessing adult patients with chronic asthma.

Section snippets

Materials and Methods

The charts of patients who had been evaluated at the adult asthma clinic of the University of Maryland Hospital between July 1, 1994, and December 31, 1996, were reviewed for inclusion into the study. Patients were excluded from the analysis if they did not have a clinical history compatible with asthma, had a current or past smoking history of >10 pack-years, or were unable to adequately perform spirometry or PEF maneuvers. During the initial clinic visit, all patients underwent a complete

Results

The records of 94 individual patients were reviewed. Of these, 27 were excluded from analysis due to an excessive smoking history (n=21) or incomplete pulmonary function data (n=6). The characteristics of the remaining 67 patients included in this analysis are presented in Table 1. Most patients included in this study were young African-American women. The frequent need for hospital-based asthma care and oral steroid therapy as well as the degree of baseline airway obstruction are indicative of

Discussion

Previous studies have demonstrated a poor relationship between asthma symptoms and objective measures of airway obstruction.3, 4, 5 The present study extends these observations to an urban-based adult population with moderate to severe asthma.

Our data demonstrate that respiratory symptoms and airway obstruction correlate poorly in adult asthmatics. Similar results have been found in prior studies. Ferguson4 recorded daily symptom scores and PEF over eight consecutive 2-week intervals in a

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    revision accepted August 13.

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