Abstract
In recent decades, mortality from non-respiratory diseases has increased in patients on long-term oxygen therapy (LTOT) for COPD (Ekström, M.P. et al. AJRCCM. Epub 2011 Jan 7). This study tests the hypothesis that co-morbidity has increased over time in oxygen-dependent COPD.
Material and methods: Patients starting LTOT for COPD between 1 January 1992 and 31 December 2008 in the national Swedish Oxygen Register were included. All registered diagnoses within five years prior to initiating LTOT were collected retrospectively from the Swedish Hospital Discharge Register, which include about 99% of all public hospitalizations in Sweden. Odds ratios (ORs) for diagnosis entities per calendar year were estimated using logistic regression adjusted for age, sex, PaO2 breathing air, FEV1 and smoking history.
Results: 6147 patients (55% women) with a mean age 71.6 ± [SD] 8.4 years were included in the analysis. Adjusted odds ratios per calendar year (OR; 95% confidence interval; P-value) increased for anaemia (1.07; 1.04-1.10; P<0.001), diabetes mellitus (1.04; 1.02-1.06; P<0.001), hypertension (1.14; 1.11-1.16; P<0.001), ischemic heart disease (1.05; 1.04-1.07; P<0.001), pulmonary embolism (1.17; 1.12-1.23; P<0.001) and for renal failure (1.20; 1.14-1.26; P<0.001). There was no time-trend for cerebrovascular disease (P=0.141) or cancer (P=0.062).
Conclusion: Co-morbidity has increased over time, which could contribute to the increased mortality from non-respiratory diseases in oxygen-dependent COPD.
- © 2011 ERS
