Tissue depletion and health related quality of life in patients with chronic obstructive pulmonary disease

The relationship between tissue depletion and decreased exercise performanc e has been well established in patients with COPD. In this study we investi gated the influence of the pattern of tissue depletion on health related qu ality of life (HRQL) and their mutual relationship with exercise capacity a nd dyspnoea. Patients with low body weight and/or low fat-free mass (FFM; using bioelect rical impedance) were categorized in three groups according to type of tiss ue depletion: loss of both FFM and Eat mass (FM), and loss of FFM or FM onl y. Handgrip strength (HGS) was used as a functional outcome measure of tiss ue depletion. Exercise performance was assessed by 12 min walking distance (12MWD) and dyspnoea by visual analogue scale (VAS). HRQL was measured with the St George's Respiratory Questionnaire (SGRQ) and the Medical Psycholog ical Questionnaire for Lung diseases (MPQL). Patients with depletion of FFM irrespective of body weight showed greater i mpairment in 12MWD, HGS, the 'activity' and impact' scores of the SGRQ and the domain 'invalidity' of the MPQL, in comparison with depleted patients w ith relative preservation of FFM. Exercise performance and dyspnoea were al so significantly related to these subscores of HRQL. In addition, dyspnoea related significantly to the domain 'symptoms' of the SGRQ. Tissue depictio n pattern remained significantly related to SGRQ-scores and the domain 'inv alidity' of the MPQL when dyspnoea and walking distance were added to the m odel as a covariates. Tissue depletion is an important determinant of HRQL independent of exercis e capacity and dyspnoea.