Reliability of the five-repetition sit-to-stand test in patients with chronic obstructive pulmonary disease on domiciliary oxygen therapy.

: To evaluate the reliability and learning effect of the five-repetition sit-to-stand test (5STSt) in severe and very severe chronic obstructive pulmonary disease (COPD) patients on domiciliary oxygen therapy compare the results with those of COPD patients not on such therapy. : Twenty-eight COPD patients were included in the domiciliary oxygen therapy group (DOTG) and 17 in the control group (CG). The participants of the groups were paired by age, sex, body mass index, and lung function. The groups performed two 5STSt (5STSt and 5STSt). : In total, 96% of the patients in the DOTG performed better on the second 5STSt (5STSt) (17.1 ± 4.63s), with an average reduction of 3.87 ± 3.50 s ( < 0.001) and a learning effect of 18.4%. In the CG, 82.3% of patients had better performance on the 5STSt (15.06 ± 3.45 s), with an average reduction of 1.38 ± 2.51 s ( = 0.035) and a learning effect of 8.39%. The 5STSt had an ICC of 0.79 (95%CI: 0.02-0.93;  < 0.001) in the DOTG and of 0.89 (95%CI: 0.65-0.96;  < 0.001) in the CG. : The 5STSt is reliable in patients with severe and very severe COPD on domiciliary oxygen therapy, with learning effect of nearly 18% in the DOTG. Thus, performing two tests is recommended to achieve the patient´s best performance in this population.