Survival on long-term oxygen therapy in chronic airflow limitation: from evidence to outcomes in the routine clinical setting

Background: Two previous randomized controlled trials (RCT) demonstrated that the administration of long-term oxygen therapy (LTOT) improved survival in selected patients with hypoxic chronic obstructive pulmonary disease (COPD) or chronic airflow limitation (CAL). Aims: The aim of the present study was to investigate whether the survival of CAL patients prescribed LTOT at Flinders Medical Centre (FMC) was gender and age related, and equivalent to that of the previous RCT. Methods: A list of patients prescribed domiciliary oxygen therapy for CAL at FMC was generated from Respiratory Unit records and hospital financial records for the supply of this therapy. Survival was compared with that reported for the original RCT, and for Swedish and Belgian COPD patients. Factors influencing survival were studied. Results: Five hundred and five (249 males, 256 females) patients were prescribed LTOT for CAL at FMC during the study period and included in the survival analysis. The patients were elderly with multiple comorbidities. Survival was less than for the control arms of the previous RCT (apart from the Medical Research Council Working Party (MRC) female group) but comparable with recent overseas data. Overall crude survival was 75.1%, 51.3%, 18.9% and 1.1% at 1, 2, 5 and 10 years respectively. Females experienced longer survival than males. Multivariate analysis indicated that age, forced expiratory volume in 1 s, body mass index (BMI) and the number of comorbidities were prognostic indicators for females; BMI was a prognostic indicator for males. A survival advantage existed for females using at least 19 h concentrator oxygen per day. Conclusions: In routine practice, survival of unselected CAL patients with multiple comorbidities is less than that reported in the original RCT.