Causative and contributive factors to asthma severity and patterns of medication use in patients seeking specialized asthma care.

STUDY OBJECTIVES: (1) To assess the prevalence of specific factors considered causative or contributive to asthma in a population of patients seen in a specialized asthma clinic, and to determine whether any of these factors were associated with more severe disease; and (2) to assess the utilization of inhaled steroids by asthma severity in this population and compare it with published guidelines of the National Heart, Lung, and Blood Institute (NHLBI). DESIGN, SETTING, AND PATIENT POPULATION: We conducted a retrospective chart review of new patients seen in a specialized asthma treatment center over a 2.5-year period and recorded the prevalence of 14 causative or contributive factors, the severity of asthma, and the intensity of treatment with inhaled corticosteroids in each patient. Patients were grouped as mild asthma vs moderate/severe asthma and compared by chi(2) analysis and stepwise logistic regression to determine whether certain factors were associated with more severe asthma. MEASUREMENTS AND RESULTS: The average number of factors recorded was 2.9 +/- 1.8 in the mild group (+/- SD) and 3.5 +/- 1.6 in the moderate/severe asthma group. This difference was statistically significant (p = 0.014). Increasing age, male gender, symptomatic gastroesophageal reflux disease (GERD), and chronic sinusitis were independently associated with more severe asthma. Suboptimal use of inhaled corticosteroids was more common in patients with mild persistent asthma, but suboptimal dosing of inhaled corticosteroids was equally common in mild and moderate/severe asthma. No relationship was found between allergen sensitization combined with exposure to cats, dogs, dust mite, or molds and more severe asthma. CONCLUSIONS: This study confirms earlier studies showing that symptomatic GERD and chronic sinusitis are important comorbid conditions in patients with asthma, both being associated with greater asthma severity. This study further shows that the doses of inhaled corticosteroids used for treatment of asthma fall short of NHLBI guidelines in the majority of patients regardless of asthma severity.