Causes of Reduced HRQOL

It has been hypothesized that impairment from COPD is a 2‑fold process, involving both systemic (whole body) impair­ment and impairment of the respiratory organ itself.

Systemic impairment is manifested as a wasting of muscles and changes in muscle metabolism. It is reflected by alterations in muscle function. Respiratory organ impairment includes impairment of ventilation and the processes associated with breathing.

This dual assault on the body results in severe impairment as the disease progresses. Patients with mild COPD may notice little or no impairment, while patients with end-stage COPD may be confined to bed. Impairment due to pathological changes in the body caused by COPD has a major impact on a patient’s HRQOL.

Weight loss is common in patients with severe COPD, and has been shown to contribute to exercise impairment. Based upon this premise, Mostert et al sought to determine the relationship (if any) between weight loss due to tissue depletion and HRQOL.

Patients with low body weight were categorized into 3 groups: loss of fat-free mass, loss of fat mass, and loss of both. Handgrip strength, the ability to walk 12 minutes, and dyspnea were all analyzed, and HRQOL was measured with the SGRQ and the Medical Psychosocial Questionnaire for Lung Diseases.

Patients with a depletion of fat-free mass had the highest scores on the SGRQ, indicating a reduced quality of life. Researchers concluded that tissue depletion—regardless of the pattern—is a determining factor in HRQOL as measured by the SGRQ. This relationship was also independent of exercise performance and dyspnea.