The Course and Prognosis of Different Forms of Chronic Airways Obstruction in a Sample from the General Population

We examined the course and prognosis in subjects selected from the general population who had chronic airflow obstruction at the time of their enrollment in a longitudinal epidemiologic study. Mortality and the rate of change in lung function were analyzed in relation to the initial clinical characteristics of the subjects. Twenty-seven subjects with symptoms and signs of asthma (Group I) had a higher survival rate and a much lower rate of decline in pulmonary function than the 45 subjects in Group III, whose clinical characteristics were more compatible with an emphysematous form of chronic obstructive pulmonary disease (COPD). The 10-year mortality among subjects in Group III (non-atopic smokers without a history of asthma) was close to 60 percent, whereas it was only 15 percent in Group I (atopic subjects or nonsmokers with known asthma). The mean overall rate of decline in forced expiratory volume in one second was 70 ml per year in Group III but less than 5 ml per year in Group I. Forty-five patients (Group II) who did not clearly fit into either Group I or III had intermediate values for survival and decline in pulmonary function. Previous data on mortality from COPD and the rate of progression of the condition, although compatible with our findings in patients who had an emphysematous form of disease, are not applicable to those with an asthmatic–bronchitic form. Better control of the progression of asthmatic bronchitis with therapy may explain its more favorable prognosis. (N Engl J Med 1987; 317:1309–14.) EARLY reports on the natural history of patients with chronic airways obstruction were in remarkable agreement, showing rates of decline in forced expiratory volumes in one second (FEV₁) in the range of 50 to 75 ml per year.^{1 2 3 4} They also demonstrated five-year survival rates of approximately 50 percent among subjects with an initial FEV₁ close to 1.0 liter.^{1,5 6 7 8} Survival was closely related to the initial spirometric measurements after the administration of bronchodilators, but the bronchodilator response itself was not an independent predictor of mortality.^9,10 These studies included a preponderance of men, almost all of them smokers, and.