Quadriceps Strength Predicts Mortality in COPD

Hospitalisation is also common in these instances.2 To moderate the risks of COPD and improve quality of life, doctors and practice nurses can refer to exercise physiology at Advanced Physiotherapy for efficient and effective outpatient COPD rehab. The triggers and timing for these referrals may be somewhat subjective, but research is ongoing to provide practitioners with easily accessible, objective data that supports care planning. To this end, an international team of researcers recently conducted a first-of-its-kind study to find cut-offs in the association of quadriceps weakness and mortality among patients with COPD.3 They reported one cut-off point. Patients who could not extend their quadriceps to push 31% of their own weight bilaterally, while seated in weight-training equipment, proved 173% more likely to experience mortality within four years. This was compared to the subset of their group who could push their own weight. In an older study, researchers established that COPD patients who could not produce enough force to move 120% of their own body mass with their dominant leg had 10% higher mortality rates, compared to patients who could produce that much force.4

While more research to create a straightforward clinical tool would be helpful, we can see that even mild loss of quadriceps strength predicts higher mortality risk in COPD. As quadriceps approach moderate and severe weakness, that weakness predicts profound increases in all-cause mortality risk. On the other hand, simple programs to improve exercise capacity in COPD have been found to produce rapid improvements. Programs involve patient education, upper limb exercises, lower limb exercises, and cardiovascular fitness. After eight or more visits, one study measured mean maximum-phonation-time (MPT) improvement from 5.8 seconds to 12.1 seconds and mean peak-expiratory-flow (PEF) improvement from 190.7 litres per minute to 324.5 litres per minute.5 MPT proves important for supporting speech function, while good PEF is known to prevent aspiration pneumonia.6 Similarly, other studies find that outpatient exercise therapy can reduce overall healthcare utilisation, decrease hospitalisations 27%, improve survival, decrease emergency department visits 21%, improve exercise tolerance, and improve dyspnea.7-12

References

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