Impact of adherence to long-term oxygen therapy on patients with COPD and exertional hypoxemia followed for one year

OBJECTIVE: To determine the impact of adherence to long-term oxygen therapy (LTOT) on quality of life, dyspnea, and exercise capacity in patients with COPD and exertional hypoxemia followed for one year. METHODS: Patients experiencing severe hypoxemia during a six-minute walk test (6MWT) performed while breathing room air but not at rest were included in the study. At baseline and after one year of follow-up, all patients were assessed for comorbidities, body composition, SpO(2), and dyspnea, as well as for anxiety and depression, having also undergone spirometry, arterial blood gas analysis, and the 6MWT with supplemental oxygen. The Saint George’s Respiratory Questionnaire (SGRQ) was used in order to assess quality of life, and the Body mass index, airflow Obstruction, Dyspnea, and Exercise capacity (BODE) index was calculated. The frequency of exacerbations and the mortality rate were noted. Treatment nonadherence was defined as LTOT use for < 12 h per day or no LTOT use during exercise. RESULTS: A total of 60 patients with COPD and exertional hypoxemia were included in the study. Of those, 10 died and 11 experienced severe hypoxemia during follow-up, 39 patients therefore being included in the final analysis. Of those, only 18 (46.1%) were adherent to LTOT, showing better SGRQ scores, higher SpO(2) values, and lower PaCO(2) values than did nonadherent patients. In all patients, SaO(2), the six-minute walk distance, and the BODE index worsened after one year. There were no differences between the proportions of adherence to LTOT at 3 and 12 months of follow-up. CONCLUSIONS: Quality of life appears to be lower in patients with COPD and exertional hypoxemia who do not adhere to LTOT than in those who do. In addition, LTOT appears to have a beneficial effect on COPD symptoms (as assessed by SGRQ scores). (Brazilian Registry of Clinical Trials - ReBEC; identification number RBR-9b4v63 [http://www.ensaiosclinicos.gov.br])