[Risk factors for mortality in chronic obstructive pulmonary disease].
OBJECTIVE
Although the factors predictive of survival in patients with chronic obstructive pulmonary disease (COPD) have been widely studied, full consensus has yet to be reached. The objective of this study was to further clarify how lung function parameters, exercise tolerance, and quality of life influence survival in patients with COPD.


METHODS
This prospective study included 60 patients diagnosed with COPD. At the start of the study, patients underwent respiratory function tests, exercise testing, and 6-minute walk test. They also answered a chronic respiratory disease questionnaire to measure health-related quality of life. Follow-up lasted 7 years.


RESULTS
Five of the 60 patients withdrew from the study. Twenty-six of the remaining 55 patients (47%) died during the study. Univariate Cox regression analysis showed a correlation between survival and age, degree of obstruction, inspiratory capacity, carbon monoxide diffusing capacity, and peak exercise tolerance. No correlation was found between survival and body mass index, PaO2, PaCO2, total lung capacity, residual volume, maximal respiratory pressures, 6-minute walk distance, or health-related quality of life. Age, degree of obstruction (measured as the ratio of forced expiratory volume in 1 second to forced vital capacity after administration of bronchodilator), and maximum minute ventilation in the exercise test were introduced initially in the multivariate Cox stepwise regression analysis, but only maximum minute ventilation remained in the final model (relative risk, 0.926; P< .001).


CONCLUSIONS
Our findings show that peak exercise tolerance is the best predictor of survival in patients with COPD.
Solanes
Ingrid
I
Departamento de Neumología, Hospital de la Santa Creu i de Sant Pau, Facultad de Medicina, Universitat Autònoma de Barcelona, Barcelona, España. isolanes@santpau.es
Casan
Pere
P
Sangenís
Mercè
M
Calaf
Núria
N
Giraldo
Beatriz
B
Güell
Rosa
R
D000368:Aged; D015992:Body Mass Index; D001993:Bronchodilator Agents / Q000627:therapeutic use; D015444:Exercise; D005260:Female; D005500:Follow-Up Studies; D006801:Humans; D008297:Male; D008451:Maximal Voluntary Ventilation; D011446:Prospective Studies; D029424:Pulmonary Disease, Chronic Obstructive / Q000188:drug therapy / Q000401:mortality*; D012129:Respiratory Function Tests; D012307:Risk Factors; D011795:Surveys and Questionnaires
D001993:Bronchodilator Agents