Course and prognosis of patients with advanced chronic obstructive pulmonary disease: Evaluation by means of functional indices

Abstract

A homogeneous group of 64 patients with advanced chronic obstructive pulmonary disease (COPD) and hypercapnia was followed from 2 to 15 years. Three quarters of the patients died during the period of study. Fourteen functional parameters were repeatedly measured under stable clinical conditions. Their importance for prognosis was assessed by means of a discriminant analysis performed on the initial values and the evolution with time of the parameters. The initial values, closely related to a bad prognosis (average survival of 6 years), are arterial carbon dioxide tension and oxygen saturation during exercise, especially variation of the latter caused by exercise, and the diffusing capacity for carbon monoxide. Once chronic hypercapnia has been reached, evolution of the disease is characterized, first, by a period of stability of all functional parameters, but with an evolution of the electrocardiogram towards cor pulmonale. This period is followed, on the average 8.5 years before death, by a rapid deterioration of one second forced expiratory volume, vital capacity, arterial carbon dioxide tension, oxygen saturation during exercise and diffusing capacity. Finally, during the last years of life, the functional condition of the patients is dominated by a marked decrease in oxygen saturation at rest.