TRENDS IN ASTHMA THERAPY IN THE UNITED-STATES - 1965-1992

Background: Many recent studies indicate an increasing morbidity and m ortality of asthma in the past two decades. This study uses data from the National Disease and Therapeutic Index (NDTI) to document and anal yze trends in drug therapy for asthma in the United States from 1965 t hrough 1992. Methods: The NDTI maintains a continuous rotating nationa l sampling of approximately 1% of US physicians in office-based practi ce proportionately representative of practicing generalists and specia lists who report issuance of drugs in treatment by diagnosis for all p atient encounters for a period of two days every 3 months. Annual summ aries of five demographic categories and 14 drug categories, character izing the asthma patient-physician encounters as percent of visits for the 28-year period of 1965 through 1992 are analyzed and characterize d. Results: Physician visits for asthma treatment have shifted somewha t from generalists to specialists in internal medicine and pediatrics. Allergists treat a significant proportion of the asthmatic population . Most patients are seen in the office. There has been no significant change in rates of inpatient visits. Age distribution of the populatio n of patient visits for asthma has been stable, but there is a steady drop in ratio of males to females. Since the mid-1970s, inhaled adrene rgic bronchodilator prescriptions have been issued at a markedly incre asing rate. Concurrently, issuance of xanthines and oral adrenergic dr ugs also rose dramatically but then decreased beginning in the mid-198 0s. Corticosteroids are used in 15% to 20% of visits, but only recentl y has the inhaled route of administration shown prominence. Allergen i mmunotherapy for asthma has decreased more than 10-fold. Cromolyn is p rescribed infrequently. Conclusions: Major changes have occurred in dr ug treatment by physicians for asthma in the US since 1965. Bronchodil ating drugs predominate, and they are being prescribed in more effecti ve forms at a generally increasing rate. Corticosteroid use has increa sed at a slower rate and in a smaller proportion of patient-visits, wh ile allergen immunotherapy has dramatically declined. The male-to-fema le ratio of asthmatic patients who visit doctors for treatment appears to be decreasing.