Sex differences in survival of oxygen-dependent patients with chronic obstructive pulmonary disease

Maria Christina L. Machado, Jerry A. Krishnan, Sonia A. Buist, Andrew L. Bilderback, Guilherme P. Fazolo, Michelle G. Santarosa, Fernando Queiroga, William M. Vollmer

Research output: Contribution to journalArticlepeer-review

88 Scopus citations


Rationale: Chronic obstructive pulmonary disease (COPD) is a leading cause of death worldwide. The prevalence of COPD is rising among women and is approaching that of men, but it is not known if sex affects survival. Objectives: To measure the survival differences between men and women with oxygen-dependent COPD. Methods: We conducted a 7-yr prospective cohort study of 435 outpatients with COPD (184 women, 251 men) referred for long-term oxygen therapy (LTOT) at two respiratory clinics in Sao Paulo, Brazil. Baseline data were collected on enrollment into oxygen therapy, when patients were clinically stable. Measurements: We examined the effect of sex on survival using Kaplan-Meier survival curves, and then used Cox proportional hazards models to control for potential confounders. Main Results: In unadjusted analyses, we observed a nonsignificant trend toward increased mortality for women (hazard ratio, 1.28; 95% confidence interval, 0.98-1.68; p = 0.07). After accounting for potential confounders (age, pack-years smoked, PaO2, FEV 1, body mass index), females were at a significantly higher risk of death (hazard ratio, 1.54; 95% confidence interval, 1.15-2.07; p = 0.004). Other independent predictors of death were lower PaO2 (p = 0.001) and lower body mass index (p < 0.05). Conclusions: Among patients with COPD on LTOT, women were more likely to die than men.

Original languageEnglish (US)
Pages (from-to)524-529
Number of pages6
JournalAmerican journal of respiratory and critical care medicine
Issue number5
StatePublished - Sep 1 2006
Externally publishedYes


  • Chronic obstructive pulmonary disease, hypoxemic
  • Sex differences
  • Survival

ASJC Scopus subject areas

  • Pulmonary and Respiratory Medicine
  • Critical Care and Intensive Care Medicine


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