[Characteristics of Mexican asthmatic subjects attending an outpatient service]. / Características de pacientes asmáticos mexicanos atendidos en consulta externa.

BACKGROUND: Despite the high prevalence of asthma in Mexico, studies describing general characteristics of these patients are scarce. OBJECTIVE: To analyze the sociodemographic, clinical and respiratory functional profile of asthmatic patients attending for the first time the outpatient service of a tertiary-level hospital, as well as to investigate treatments already received and the abandonment rate. METHODS: Adolescent and adult asthmatic subjects seen from February 2000 to November 2002 in the outpatient service of the National Institute of Respiratory Diseases, in Mexico City, were prospectively studied. Sociodemographic information was gathered and clinical and spirometric evaluations were carried out. The severity of the disease was classified according to international criteria. RESULTS: A total of 1403 patients between 12 and 82 years of age, with predominance of the female gender, were included in the analysis. An 88.7% of patients had the mildest forms of the disease, 10% had moderate asthma, and 1.3% had severe asthma. While 21.4% had never received anti-asthma treatment, about one third of the remaining patients had received corticosteroids, independently of the asthma severity, indicating an over-treatment of the intermittent form of the disease and an under-treatment of persistent forms. A high abandonment rate (65.7%) was observed. A positive bronchodilator test was observed in 30.3% of patients with intermittent asthma, though this proportion increased to about 67% in those with moderate and severe asthma. CONCLUSION: Mildest forms of the disease predominate among asthmatic patients attending for the first time an outpatient service, with a still very high frequency of inadequate use of corticosteroids.