The minimal important difference for Glittre-ADL test in patients with chronic obstructive pulmonary disease.

Objective: To determine Glittre-ADL test minimal important difference in patients with chronic obstructive pulmonary disease.

Methods: This is quasi-experimental study. Sixty patients with moderate to very severe chronic obstructive pulmonary disease (age 64.1, SD=9.09 years; forced expiratory volume in the first second 37.9, SD=13.0% predicted participated in a pulmonary rehabilitation program based on physical training, conducted over 24 sessions supervised, three times a week, including aerobic training in treadmill and resistance training for upper limbs and lower limbs. The main outcomes were the Glittre-ADL test and six-minute walk test, before and after 24 sessions of pulmonary rehabilitation. The minimal important difference was established using the distribution and anchor-based methods.

Results: Patients improved their functional capacity after the pulmonary rehabilitation. The effect sizes of Glittre-ADL test and six-minute walk test improvement were similar (0.45 vs 0.44, respectively). The established minimal important differences ranged from -0.38 to -1.05. The reduction of 0.38min (23s) corresponded to a sensitivity of 64% and a specificity of 69% with an area under the curve of 0.66 (95%CI 0.51-0.81; p=0.04). Subjects who achieved the minimal important difference of -0.38min for the Glittre-ADL test had a superior improvement of approximately 42m in the six-minute walk test when compared to patients who did not.

Conclusions: The present findings suggest -0.38min as the minimal important difference in the time spent in the Glittre-ADL test after 24 sessions of pulmonary rehabilitation in patients with chronic obstructive pulmonary disease.

Trial Registration: NCT03251781 (https://clinicaltrials.gov/ct2/show/NCT03251781).