One long-term study conducted in Sweden showed a 3.8% drop in the risk of death for Chronic Obstructive Pulmonary Disease (COPD) patients, who took part in oxygen therapy over the course of 18 years. Even though this is still a small percentage, one has to consider how many people were included in this study. 7,628 adults between the ages of 66 to 73 were monitored and 5,497 died after they had stopped with the oxygen therapy. The study started in January 1987 and concluded in December of 2004.
The people who took part in the study died from various disease, some of which did not relate to COPD. While 76% of those who died, died from respiratory illness, 16% died from a circulatory disease, 7.6% from cancer and 1.1% from digestive organ disease.