The Predictive Ability of 4MGS in IPF

This observational study is investigating a simple test of usual walking speed, measured using the 4 metre gait speed (4MGS) test in patients with a lung disease called Idiopathic Pulmonary Fibrosis (IPF). Drug development for this disease is slow in part because there is a lack of reliable measurements that can assess the effectiveness of treatment. Death and hospital admissions are currently considered meaningful endpoints in research trials due to the lack of fully validated surrogate endpoints in IPF. Using surrogate endpoints could reduce the sample size, cost and duration of clinical trials in IPF perhaps permitting more rapid drug development. Slow walking speed has been shown to be consistently associated with survival and a risk factor for disability, institutionalisation and hospitalisation in older adults and people with another lung disease called Chronic Obstructive Pulmonary Disease (COPD). We are interested to see whether usual walking speed and change in usual walking speed over 6 months predicts death and hospital admissions in IPF patients. This will help inform us of the potential use of 4MGS as a surrogate endpoint. To do this, participants who consent to taking part in the study will be timed walking at their usual walking speed over a distance of 4 metres (13.12 feet) at one time point and then six months later. Incidence of mortality and non-elective hospital admissions will be assessed at 12 months.

Inclusion criteria

• IPF diagnosis according to NICE guidelines

Exclusion criteria

• Significant co-morbidities that would limit walking ability, exercise capacity or make exercise unsafe (e.g. unstable ischaemic heart disease, neuromuscular disease, severe hip/lower limb joint pain, peripheral vascular disease, lower limb amputation)
• Any patient whom the chief investigator feels it is unsafe to exercise (e.g. unstable cardiovascular disease)
• Any condition that precludes providing informed consent e.g. cognitive impairment or poor English