Physical activity decline may predict IPF progression

A decline in daily physical activity (DPA) among patients with idiopathic pulmonary fibrosis (IPF) over a year is noteworthy and disproportionate to a decline in pulmonary physiology, suggests a recent study, noting that this change in DPA may be used as a prognostic tool to assess disease progression.

“Patients with IPF have reduced levels of DPA, [but] little is known about how DPA changes as disease progresses,” the authors said.

Fifty-four patients with IPF had their DPA monitored at baseline and at 6 and 12 months using a SenseWear armband for 7 consecutive days. At each time point, participants completed the Hospital Anxiety and Depression scale, St. George's Respiratory Questionnaire, and Leicester Cough Questionnaire. They also provided clinical data, including forced vital capacity (FVC), diffusion capacity of carbon monoxide, and 6-min walk distance (6MWD).

IPF patients logged a total of 3,887 and 3,326 baseline and 12-month daily step count, respectively. At 12 months, a significant decrease in daily step count (mean, 645; p=0.02) and total energy expenditure (mean, 486 kJ; p=0.01) was observed. Such decline in daily step count over a year was proportionally larger than the decline in lung function.

In addition, the annual change in DPA demonstrated a weak-to-moderate association with annual change in FVC % predicted and 6MWD (range, 0.34–0.45). Moreover, change in physical activity was not associated with long-term survival.