Desaturation during exercise (6MWT) in COPD patients provides important additional information regarding the disease course and prognosis.

Aim: To perform follow up of COPD patients with and without desaturation during a 6MWT and determine mortality and its causes.

Patients and methods: Ninety patients with COPD, IIB-IVD stage by GOLD and age 65.1 ± 9.4; FEV1% = 46.1% ± 14.9%; ?RC = 2.2 ± 0.8; ??? = 20.5 ± 6.8 were followed up regarding mortality and its causes for a period of 7.2 ± 3.6 years. The patients were divided into two groups: without desaturation - A (n=46; FEV1% = 51.7% ± 13.3%) and with desaturation - B (n=44; FEV1% = 40.2% ± 14.2%) depending on whether desaturation occurred during the 6MW?. Desaturation was assumed to occur when SpO2 decreased by ?4% and dropped to ?88% for at least 3 min. We divided the most important causes of death into 4 groups ? respiratory failure, cardio-vascular causes, oncological causes and other causes.

Results: In group ? 23 patients died (50%), whereas in group ? 33 deaths were observed (75%). A significant difference was found in the survival rate between patients with and without desaturation: 6.7 ± 0.6 years against 9,5 ± 0.6 years. (Kaplan-Meier; Log-rank test, p<0.002). The most frequent cause of death was respiratory failure, which occurred more frequently and more rapidly in the patients with desaturation. We did not find any significant differences regarding the cardio-vascular, oncological and other causes of death between the two groups.

Conclusions: Patients with COPD and desaturation during exercise have worse prognosis regarding mortality. They die earlier and most frequently the cause of death is progressive respiratory failure.