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Comorbidity and sex-related differences in mortality in oxygen-dependent chronic obstructive pulmonary disease.

Ekström, Magnus P; Jogréus, Claes and Ström, Kerstin LU (2012) In PLoS ONE 7(4).
Abstract
BACKGROUND:

It is not known why survival differs between men and women in oxygen-dependent chronic obstructive pulmonary disease (COPD). The present study evaluates differences in comorbidity between men and women, and tests the hypothesis that comorbidity contributes to sex-related differences in mortality in oxygen-dependent COPD.



METHODS:

National prospective study of patients aged 50 years or older, starting long-term oxygen therapy (LTOT) for COPD in Sweden between 1992 and 2008. Comorbidities were obtained from the Swedish Hospital Discharge Register. Sex-related differences in comorbidity were estimated using logistic regression, adjusting for age, smoking status and year of inclusion. The effect... (More)
BACKGROUND:

It is not known why survival differs between men and women in oxygen-dependent chronic obstructive pulmonary disease (COPD). The present study evaluates differences in comorbidity between men and women, and tests the hypothesis that comorbidity contributes to sex-related differences in mortality in oxygen-dependent COPD.



METHODS:

National prospective study of patients aged 50 years or older, starting long-term oxygen therapy (LTOT) for COPD in Sweden between 1992 and 2008. Comorbidities were obtained from the Swedish Hospital Discharge Register. Sex-related differences in comorbidity were estimated using logistic regression, adjusting for age, smoking status and year of inclusion. The effect of comorbidity on overall mortality and the interaction between comorbidity and sex were evaluated using Cox regression, adjusting for age, sex, Pa(O2) breathing air, FEV(1), smoking history and year of inclusion.



RESULTS:

In total, 8,712 patients (55% women) were included and 6,729 patients died during the study period. No patient was lost to follow-up. Compared with women, men had significantly more arrhythmia, cancer, ischemic heart disease and renal failure, and less hypertension, mental disorders, osteoporosis and rheumatoid arthritis (P<0.05 for all odds ratios). Comorbidity was an independent predictor of mortality, and the effect was similar for the sexes. Women had lower mortality, which remained unchanged even after adjusting for comorbidity; hazard ratio 0.73 (95% confidence interval, 0.68-0.77; P<0.001).



CONCLUSIONS:

Comorbidity is different in men and women, but does not explain the sex-related difference in mortality in oxygen-dependent COPD. (Less)
Please use this url to cite or link to this publication:
author
organization
publishing date
type
Contribution to journal
publication status
published
subject
in
PLoS ONE
volume
7
issue
4
publisher
Public Library of Science
external identifiers
  • wos:000305349100032
  • pmid:22563405
  • scopus:84860355888
ISSN
1932-6203
DOI
10.1371/journal.pone.0035806
language
English
LU publication?
yes
id
035cbbcc-ce04-4948-8f74-a1d8995a7555 (old id 2609076)
alternative location
http://www.ncbi.nlm.nih.gov/pubmed/22563405?dopt=Abstract
date added to LUP
2012-06-03 12:48:26
date last changed
2017-03-19 03:51:54
@article{035cbbcc-ce04-4948-8f74-a1d8995a7555,
  abstract     = {BACKGROUND:<br/><br>
It is not known why survival differs between men and women in oxygen-dependent chronic obstructive pulmonary disease (COPD). The present study evaluates differences in comorbidity between men and women, and tests the hypothesis that comorbidity contributes to sex-related differences in mortality in oxygen-dependent COPD.<br/><br>
<br/><br>
METHODS:<br/><br>
National prospective study of patients aged 50 years or older, starting long-term oxygen therapy (LTOT) for COPD in Sweden between 1992 and 2008. Comorbidities were obtained from the Swedish Hospital Discharge Register. Sex-related differences in comorbidity were estimated using logistic regression, adjusting for age, smoking status and year of inclusion. The effect of comorbidity on overall mortality and the interaction between comorbidity and sex were evaluated using Cox regression, adjusting for age, sex, Pa(O2) breathing air, FEV(1), smoking history and year of inclusion.<br/><br>
<br/><br>
RESULTS:<br/><br>
In total, 8,712 patients (55% women) were included and 6,729 patients died during the study period. No patient was lost to follow-up. Compared with women, men had significantly more arrhythmia, cancer, ischemic heart disease and renal failure, and less hypertension, mental disorders, osteoporosis and rheumatoid arthritis (P&lt;0.05 for all odds ratios). Comorbidity was an independent predictor of mortality, and the effect was similar for the sexes. Women had lower mortality, which remained unchanged even after adjusting for comorbidity; hazard ratio 0.73 (95% confidence interval, 0.68-0.77; P&lt;0.001).<br/><br>
<br/><br>
CONCLUSIONS:<br/><br>
Comorbidity is different in men and women, but does not explain the sex-related difference in mortality in oxygen-dependent COPD.},
  articleno    = {e35806},
  author       = {Ekström, Magnus P and Jogréus, Claes and Ström, Kerstin},
  issn         = {1932-6203},
  language     = {eng},
  number       = {4},
  publisher    = {Public Library of Science},
  series       = {PLoS ONE},
  title        = {Comorbidity and sex-related differences in mortality in oxygen-dependent chronic obstructive pulmonary disease.},
  url          = {http://dx.doi.org/10.1371/journal.pone.0035806},
  volume       = {7},
  year         = {2012},
}