Test of physical abilities designed for COPD may work well for CF

Glitter-ADL test appears better than 6MWD at capturing exercise capacity

Marisa Wexler, MS avatar

by Marisa Wexler, MS |

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A woman is shown walking.

A test of physical function called Glittre-ADL may be better than the standard six-minute walk test at identifying physical limitations in people with cystic fibrosis (CF), a study reports.

“To our knowledge, this is the first study to evaluate the performance of CF patients on TGlittre and to compare it with their [6-minute walk distance],” scientists wrote in the study “Evaluating the contribution of the Glittre-ADL test in adults with cystic fibrosis,” published in Physiotherapy Research International.

Despite the availability of CFTR modulator therapies and other improvements in CF care, patients continue to experience difficulties with physical activity, due to disease symptoms like digestive issues that affect nutrition and systemic inflammation that limits exercise tolerance, the team noted.

“The effects of CFTR modulators on extra-pulmonary CF disease manifestations are less clear,” the scientists wrote.

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Glittre-ADL test includes walking, stair climbing, and moving weighted objects

In clinical practice and research, objective tests are useful in tracking patients’ physical health and exercise capacity.

The six-minute walk test, or 6MWT, is a standard assessment used to determine exercise capacity in people who can walk. As its name suggests, the 6MWT simply measures the distance that a patient quickly can walk in six minutes.

Recently, scientists created the Glittre‐ADL test, or TGlittre, to assess exercise capacity in people with chronic obstructive pulmonary disease (COPD). This test measures the time it takes a patient to complete five walking laps of a 10-meter course (about 32 feet) with stations that include going up and down stairs, sitting and standing from a chair, and moving weighted objects.

Since it involves more than just walking, and particularly use of the arms and hands, TGlittre is being proposed as a better reflection than the 6MWT of overall physical abilities in people with lung diseases.

A research team in Brazil decided to compare TGlittre with the more standard 6MWT in people with CF. Their study enrolled 34 adult patients attending their Rio de Janeiro clinic and an equal number of healthy adults as a control group, all of whom took both tests twice. Patients’ median age was 23, and none were using CFTR modulators.

Patients with better test scores tended to be more active in everyday life

Results showed that the average TGlittre time was significantly poorer in the CF patients relative to the controls (134% vs. 107%). However, 6MWT scores were comparable between the two groups, a finding that suggests TGlittre may be more sensitive than 6MWT at detecting physical limitations in CF patients.

“The main findings of the present study were that patients with CF took longer to perform the TGlittre compared to controls, with no difference being observed between these groups in the 6MWT,” the scientists wrote.

They noted that, in people with or without CF, scores on both the TGlittre and the 6MWT tended to be better on the second test, likely because participants were more comfortable with the process. As such, the scientists highlighted the importance of doing a few tests in order to get reliable results.

Statistical analyses showed that CF patients with better TGlittre scores also tended to have better 6MWT scores and to be more physically active in their day-to-day life. These people also tended to do better in tests in measures of hand grip strength and the amount of oxygen carried in the blood, and they generally reported less severe gastrointestinal symptoms.

Study findings collectively support TGlittre as a useful measure of exercise ability in CF patients, the researchers noted. Further studies, however, are needed to assess how this measure can best be used to study CF and help with patient care.

“In addition, TGlittre could also be an interesting tool to evaluate the impact of CFTR modulators in order to better understand how they modify exercise intolerance and thus identify appropriate intervention strategies,” the team concluded.