Lack of correlation of symptoms with specialist-assessed long-term asthma severity

Study objectives: To validate three indicators of asthma severity as define d in the National Asthma Education Program (NAEP) guidelines (ie, frequency of symptoms, degree of airflow obstruction, and frequency of use of oral g lucocorticoids), alone and in combination, against severity as assessed by pulmonary specialists provided with 24-month medical chart data. Design: Cross-sectional comparison of questionnaire and clinical-based mark ers of asthma severity with physician-assessed severity based on chart revi ew. The pulmonologists did not have access to the results of the baseline e valuations when making their severity assessments. Setting and participants: Study participants were 193 asthmatic members (ag e range, 6 to 55 years) of a large health maintenance organization who unde rwent a baseline evaluation as part of a separate longitudinal study. This evaluation consisted of spirometry, skin prick testing, and a sun ey that i ncluded questions on symptoms and medication use. The participants in the a ncillary study were selected, based on their baseline evaluation, to reflec t a broad range of asthma severity. Results: Based on the chart review, 86 of the study subjects (45%) had mild disease, 90 (45%) had moderate disease, and 17 (9%) had severe disease. Th is physician-assessed severity correlated highly (p less than or equal to 0 .013) with NAEP-based indices of severity based on oral glucocorticoid use (never, infrequently for attacks, frequently for attacks, and daily use) an d on spirometry (FEV1 > 80% predicted, 60 to 80% predicted, and <60% predic ted). It did not, however, correlate with current asthma symptoms (less tha n or equal to once/week, 2 to 6 times/week, daily) (p = 0.87). A composite severity score based on spirometry and the glucocorticoid use data still pr ovided an overall agreement of 63%, with a weighted kappa of 0.40. Conclusions: While current symptoms are the most important concern of patie nts with asthma, they reflect the current level of asthma control more than underlying disease severity. Investigators must therefore use caution when comparing groups of patients for whom severity categorization is based lar gely on symptomatology. This observation, that symptoms alone do not reflec t disease severity, becomes even more important as health-care delivery mov es closer to protocols/practice guidelines and "best treatment" programs th at rely heavily on symptoms to guide subsequent treatment decisions.