The role of expectations on the respiratory performance of people with Chronic Obstructive Pulmonary Disease

Introduction: Previous studies have investigated the effects of oxygen therapy both during sleep and daily life, investigating its influences in patients with hypoxaemia. However, there are no studies investigating the role of oxygen (O2) during the performance of the 6 Minute Walking Test (6MWT) compared to a placebo. The study aimed to investigate the role of the placebo effect during oxygen therapy in patients with moderate Chronic Obstructive Pulmonary Disease (COPD) (GOLD2). Methods: An experimental, randomised, two-arm, counterbalanced study was carried out, involving 95 people with COPD (68.4% male, average age 67). Participants were randomised and assigned to two groups: 1) Participants who usually use oxygen (O2): in addition to standard care, they underwent the 6MWT using compressed medical air (RA) cylinders, believing that O2 was inside the concentrator. The same, subsequently, underwent the 6MWT, thanks to the use of concentrators of O2, believing that inside the cylinder there was O2. The sequence of this group was thus characterised as follows: ABC (A=Baseline, B=Air, C=Oxygen). 2) Participants who do not usually use O2: the same methodology was used, with a different sequence (ACB). Mini-Mental Status Examination (MMSE), to assess cognitive impairment; Modified British Medical Research Council questionnaire (mMRC), to detect dyspnoea; Fatigue Severity Scale (FSS); Simple Spirometry, were taken at baseline. Saturation (SpO2), heart rate and blood pressure were measured at baseline, at 3':30'' and at the end of the 6MWT, from which the main outcome of the study was taken. Results: A repeated measures ANOVA was performed to compare the effect of oxygen usage on the 6MWT. There was no statistically significant difference in the 6MWT between the two groups (F(2, 1) = 0.113, p = 0.888). Discussion: Whilst oxygen therapy is and remains an important treatment for COPD patients, working on their beliefs and expectations can improve their care processes.