Serial studies of 100 patients with chronic airway obstruction in London and Chicago.

One hundred patients with chronic airway obstruction, 50 in Chicago and 50 in London, were studied by standardized techniques in 1961. The results of the initial studies, previously reported, showed that the patients in the two cities were similar; using clinical and physiological criteria based on pathological studies, the patients were divided into three types-emphysematous type A, bronchial type B, and an indeterminate type X. The patients were studied again in succeeding years, 1962-65. During this time 26 died, 19 due to their respiratory disease; these 19 patients were initially more breathless, had a higher incidence of cor pulmonale, and had more severe airway obstruction and higher carbon dioxide pressures than the remainder. Type B patients (mortality 36%) had a worse prognosis than either type A (15%) or type X (12%). Of the measurements made, high carbon dioxide pressures were most closely related (P<0 001) to mortality. During the period of follow-up about one-third of the patients who did not die became more short of breath and developed more severe airway obstruction and carbon dioxide retention: about 10% showed definite improvement in symptoms and pulmonary function. The F.E.V.1.0 declined on average by 46 ml./year, 4-8% of the initial value; V.C. declined by 120 ml./year, 4-0% of the initial value; mixed venous Pco2 increased 1 mm. Hg/year. The changes that occurred during this time confirmed the previously reported similarity between the patients attending the two clinics. Although the incidence of bronchitic exacerbations was similar in the two cities, such illnesses in the London patients led to more frequent and more prolonged incapacity. In 1961 a joint study of patients with chronic airway obstruction was begun in London and Chicago. The series comprised 50 patients from the Bronchitis Clinic at Hammersmith Hospital and 50 from the Emphysema Clinic at the University of Chicago Hospitals. The patients were men aged between 45 and 65 years with irreversible airway obstruction (forced expiratory volume less than 15 1. in the first second). They were studied by the same standardized clinical and physiological techniques in the two clinics and were found to present a broadly similar range of clinical and physiological abnormality (Fletcher, Jones, Burrows, and Niden, 1964). We report here the results of yearly studies on these patients during the following three years. The clinical and physiological changes have been compared in the two clinics and in the main clinical types of patient. METHODS The …