Sex differences in mortality and clinical expressions of patients with chronic obstructive pulmonary disease. The TORCH experience

Abstract

Rationale: There is limited knowledge regarding sex differences and outcomes in patients with chronic obstructive pulmonary disease (COPD).

Objectives: Determine sex differences in survival, causes of death, and patient-centered outcomes in the 3-year Toward a Revolution in COPD Health (TORCH) study.

Methods: A total of 1,481 women and 4,631 men with COPD were enrolled in TORCH, a trial comparing salmeterol, 50 μg, plus fluticasone propionate, 500 μg, twice a day and each component individually. Causes of death were determined by an endpoint committee. Sex differences in survival were explored using a Cox proportional hazards model adjusted for other baseline factors. Exacerbation rate was compared using a negative binomial model. Dyspnea was evaluated using the Medical Research Council scale and health status using the St. George's Respiratory Questionnaire.

Measurements and main results: At baseline, women were younger (63 vs. 66 yr), had higher FEV(1) (47% vs. 44% predicted), and worse St. George's Respiratory Questionnaire (51.3 vs. 48.7) and Medical Research Council score. During the study, 707 (15.3%) men and 168 (11.3%) women died. After adjusting for differences in baseline factors, the risk of dying was 16% higher in men than in women; however, this was not statistically significant (hazard ratio 1.16 [95% CI, 0.98-1.39]). Causes of death were similar in women and men. Exacerbation rate was 25% higher in women than in men.

Conclusions: Women enrolled in TORCH had a lower mortality rate than men but similar causes of death. The risk of dying was similar in women and men after adjusting for important baseline variables. Women reported more exacerbations, and worse dyspnea and health status scores than men. Clinical trial registered with www.clinicaltrials.gov (NCT00268216).