Minimal Important Difference of Walking Test in Subjects With Bronchial Asthma
Condition: Outcome; Asthma; Pulmonary Rehabilitation
MeSH terms: Asthma
Study type: Observational

Summary: 
      The Six Minute Walking Test (6MWT) efficiently represents the exercise capacity in subjects
      with chronic respiratory disease, as asthma. The variation of the walking distance is a
      parameter used to evaluate the effectiveness of pharmacologic ando non-pharmacologic
      interventions, as Pulmonary Rehabilitation (PR). However, statistically significant changes
      in the walking distance do not always represent clinically significant variations.The aim of
      this prospective study is to determine the Minimal Important Difference (MID) for the 6MWT in
      subjects affected by asthma, regardless of the severity of the disease.
    

Detailed description: 
      The Six Minute Walking Test (6MWT) efficiently represents the exercise capacity in subjects
      with chronic respiratory disease, as asthma. The variation of the walking distance is a
      parameter used to evaluate the effectiveness of pharmacologic and non-pharmacologic
      interventions, asPulmonary Rehabilitation (PR). However, statistically significant changes in
      the walking distance do not always represent clinically significant variations. For this
      reason, it is important to understand in terms of clinical impact, how to interpret the 6MWT
      when the walking distance changes over time in the same subject (for example, at the
      beginning and after PR) or when it differs between subjects (some subjects may improve more
      and some subjects less). It is not enough to state that the intervention works, it is
      necessary to say how much it works. The demonstration of a clinically relevant effect must be
      the primary goal of every treatment. A clinically relevant effect is defined as the minimum
      achievable benefit, which may lead the medical doctor to change his strategy towards the
      patient, for example by recommending a particular therapy or treatment. The international
      scientific community calls the minimum achievable benefit with different names; one of the
      most common is the Minimal Important Difference (MID). The identification of MID is relevant
      for the clinician, for the agency that is paying the treatment, for the Regulatory Agency and
      is equally important for the patient for whose health these groups are responsible. MID for
      6MWT has been estimated in subjects with different respiratory diseases and not. In Chronic
      Obstructive Pulmonary Diseases, a variation of 25 meters is considered significant. Recent
      studies have shown that asthmatic subjects cover a distance of about 500 meters during 6MWT,
      and that this distance improves after PR on average of 30-60 meters. Up to-day, however, the
      6MWT MID in asthmatic patients has not been investigated.

      The aim of this prospective study is to determine the MID for the 6MWT in subjects affected
      by asthma, regardless of the severity of the disease.
    

Intervention name(s): 6 minute walking test
Intervention type(s): Diagnostic Test
Intervention description(s): change of 6MWT pre to post pulmonary rehabilitation
Observational model: Cohort
Time perspective: Prospective
Sampling method: Non-Probability Sample
Study population: 
        Subjects hospitalized in a Rehabilitation Center to complete a pulmonary rehabilitation
        programme