| The efficacy of long-term oxygen therapy (LTOT) was established in 1980 when two multi-center trials reported improved survival in patients who used oxygen continuously versus fewer hours per day. In 1990, the VA Pittsburgh Healthcare System initiated a computer-based system to track outcomes in LTOT patients. Entries included: height, weight, oxygen liter flow, and 6 minute walk distance. In addition, 124 patients in a prospective study were followed for 2-years to assess change in quality of life using the Sickness Impact Profile (SIP), Medical Outcome Study SF-36 (SF-36), and Chronic Respiratory Questionnaire (CRQ). A retrospective analysis was completed to determine: (1) the duration of survival following prescription of LTOT; (2) differences in survivors and nonsurvivors in regard to: age, body mass index (BMI), oxygen flow requirements (LPM), PaCO2, exercise tolerance (6MWD), general HRQoL (SF-36), or disease-specific HRQoL (SIP, CRQ); (3) patient perception of illness when evaluated using the SIP, CRQ, and SF-36. Mean duration of survival was 3.4 years. Results showed significant differences in survivors and non-survivors in regard to age, 6MWD, and BMI. Using Cox Regression Analysis, lower oxygen liter flow at rest and during sleep and a longer 6MWD predicted longer survival. The mastery component of the CRQ showed significant differences between survivors and non-survivors at study entry. Changes over time were found on the SF-36 mental component and CRQ dyspnea component. There was evidence of consistency when comparisons were made between the three HRQoL measures on sub-scores designed to measure the same concepts. |
