The Impact Of Long-term Oxygen Therapy On COPD Patients With Exercise-induced Hypoxemia: META Analysis

Objective:Currently, most researches regarding the impact of long-term oxygen on stable chronic obstructive pulmonary disease(COPD) patients with exercise-induced hypoxemi a are small sample studies, and the results are contradictory. Some studies concluded t hat the long-term oxygen therapy benefits such patients in the long run, However oth er studies thought there is no significant benefits of long-term oxygen therapy to thes e patients. In this study, using META analysis method to summarize the relative indep endent studies, we aimed to investigate the effect of long-term use of oxygen therapy on COPS patients with stable movement hypoxemia, The exercise capacity, quality of life, blood oxygen saturation, dyspnea, adverse events and mortality in patients are th e primary concentration of this study.Method:1. Search strategyWe searched for studies indexed in the Pub Med, Cochrane Library, EMBASE dat abases, as well as China National Knowledge Infrastructure(CNKI) and Chinese Biom edical Literature Database(CBM). The used key terms are the following: “pulmonary disease OR chronic obstructive,and(oxygen* or 02 or LTOT) or exertional hyoxemia”2. Study seletion and meta analysisWe selected the randomized controlled studies(RCTs) which compared the effect of long-term oxygen therapy with that of placbo therapy on COPD patients with exer cise-induced hypoxemia for the meta analysis. Two independent evaluators screened t he literatures, extracted data, evaluated the quality and cross-checked. Rev Man5.3 stati stical software was used for the statistical analysis. The data about athletic ability, quality of life, oxygen saturation, dyspnea, adverse events, and mortality were extractedfrom the studies selected.RESULTS:Five RCTs. including 351 patients with stable COPD.were involved in the meta-analysis. The results are the following:1. athletic abilityApplication of long-term oxygen therapy can improve exercise capacity in stable COPD patients with exercise-induced hypoxemia, increase 6-minute walk test distance[weighted mean difference(WMD) for 20.77,95% confidence interval(CI) 0.96 to 44.57, Z=2.05,P=0.04)]2. quality of lifeApplication of long-term oxygen therapy can improve quality of life in stable COPD patients with exercise-induced hypoxemia in part(dyspnea and fatigue part), CR Q-difficulty breathing[WMD for-0.28,95% CI-0.54 to 0.11, Z=3.43,P=0.0006], CR Q-fatigue[WMD for-0.21,95% CI-0.33to-0.08, Z=3.26,P=0.001]3. dyspnea scaleApplication of long-term oxygen therapy can improve dyspnea scale in stable COPD patients with exercise-induced hypoxemia[WMD for-0.65,95% CI-1.03 to 0.28, Z=3.43,P=0.0006]4. Arterial oxygen saturationApplication of long-term oxygen therapy may improve arterial oxygen saturation levels in stable COPD patients with exercise-induced hypoxemia[WMD for6.51,95%CI 5.57to7.46, Z=13.55,P<0.0001]5. MortalityThe study could not determine the effects of long-term oxygen therapy in patients with stable COPD mortality sports hypoxemia.6. Adverse EventsThe study could not determine the occurrence of adverse events did not necessarily have a causal relationship with oxygen therapy.Conclusion:For patients with stable with COPD exercise hypoxemia:1. oxygen therapy can increase 6-minute walk test distance and 5-minute walk test distance,and can improve exercise capacity2. oxygen therapy can improve the arterial oxygen saturation levels and degree of breathing difficulty during the exercise.3. oxygen therapy can partly improve the quality of life(dyspnea, fatigue)., However anxiety and depression improvement is not obvious.4. This included study time are too short, can not explain oxygen therapy on mortality impact, nor whether the incidence of adverse events are the exact impact and certain causal link.We could not confirm the impact of oxygen therapy on mortality and adverse events incidence.