Four-meter gait speed predicts mortality in IPF
AT ATS 2018
In an interview, Ms. Nolan characterized the results as “one piece of the puzzle in answering whether 4-meter gait speed is a useful test for clinicians and researchers. It needs to be taken in the context of 4-meter gait speed in other populations as well as with what we’re finding in patients with IPF. We know that this test is reliable, valid, and responsive to treatment. Now we know that it has predictive capacity as well.”
During her presentation, she cited potential reasons why change in gait speed is associated with survival. “Firstly, gait speed has been described as a clinical indicator of multisystem well-being and the ‘sixth vital sign,’ ”she said. “Walking ability and speed rely on multiple factors and the integration of many systems, cardiovascular and otherwise. We know that pulmonary rehab has multiple benefits and improves these systems, and it’s plausible that change in gait speed may be a surrogate marker for, say, improvement in exercise capacity or health status. But the precise mechanism requires verification.”
Ms. Nolan acknowledged certain limitations of the study, including the fact that contemporaneous measurement of full lung function testing and pulmonary hypertension diagnosis were not available at the time of the study. “Therefore, we were unable to account for [diffusing capacity of the lung for carbon monoxide] and pulmonary hypertension diagnosis,” she said. “Secondly, we were unable to identify the precise cause of death from the national database of harm and care records, but this corroborates previous data which suggest that it’s difficult to reliably discern if a death is IPF- or non-IPF related. Lastly, we know that the benefits of pulmonary rehab experienced by IPF patients tend to wane after 6 months. It would be interesting to compare the short-term improvements in gait speed that we observed to more sustained improvements, to identify whether this impacts prognostability.”
National Institute for Health Research funded the study. Ms. Nolan reported having no financial disclosures.
*Correction, 5/23/18: An earlier version of this article misstated the 4-meter gait speed cutoff point.
SOURCE: Nolan CM et al. ATS 2018, Abstract A2456.
