Functional exercise capacity and health-related quality of life in people with asbestos related pleural disease: an observational study

Our plain-English summary of Functional exercise capacity and health-related quality of life in people with asbestos related pleural disease: an observational study, by M.T. Dale, Z.J. McKeough, P.A. Munoz, et al (BMC Pulmonary Medicine, 2013).

The study

• Authors: M.T. Dale, Z.J. McKeough, P.A. Munoz, P. Corte, P.T. Bye, J.A. Alison
• Journal: BMC Pulmonary Medicine
• Published: 2013;13:1
• Cited by: 17 articles, as counted by NIH iCite
• Read it: PubMed · Publisher · Free full text

Abstract

Background: Functional exercise capacity in people with asbestos related pleural disease (ARPD) is unknown and there are no data on health-related quality of life (HRQoL). The primary aims were to determine whether functional exercise capacity and HRQoL were reduced in people with ARPD. The secondary aim was to determine whether functional exercise capacity was related to peak exercise capacity, HRQoL, physical activity or respiratory function.

Methods: In participants with ARPD, exercise capacity was measured by the six-minute walk test (6MWT) and incremental cycle test (ICT); HRQoL by the St George's Respiratory Questionnaire and physical activity by an activity monitor worn for one week. Participants also underwent lung function testing.

Results: 25 males completed the study with a mean (SD) age of 71 (6) years, FVC 82 (19)% predicted, FEV1/FVC 66 (11)%, TLC 80 (19)% predicted and DLCO 59 (13)% predicted. Participants had reduced exercise capacity demonstrated by six-minute walk distance (6MWD) of 76 (11)% predicted and peak work rate of 71 (21)% predicted. HRQoL was also reduced. The 6MWD correlated with peak work rate (r=0.58, p=0.002), St George's Respiratory Questionnaire Total score (r=-0.57, p=0.003), metabolic equivalents from the activity monitor (r=0.45, p<0.05), and FVC % predicted (r=0.52, p<0.01).

Conclusions: People with ARPD have reduced exercise capacity and HRQoL. The 6MWT may be a useful surrogate measure of peak exercise capacity and physical activity levels in the absence of cardiopulmonary exercise testing and activity monitors.

Trial Registration: ANZCTR12608000147381.

In plain English

This observational study in Sydney, Australia, tested 25 men (average age 71) with asbestos related pleural disease, defined as asbestos-related diffuse pleural thickening and/or rounded atelectasis. People with mesothelioma, or with pleural plaques as their only sign of dust exposure, were excluded. The men did two six-minute walk tests, a cycling test to their limit, a breathing-related quality-of-life questionnaire and lung function tests. They were also asked to wear an activity monitor for a week, and 23 gave usable activity data. Average walk distance was 76% of the predicted normal value and peak cycling work rate was 71% of predicted. The questionnaire showed poorer quality of life in all its areas. Longer walk distance went with higher peak work rate (r=0.58), better quality of life on the questionnaire (r=-0.57), more daily activity in metabolic equivalents (r=0.45) and higher forced vital capacity (r=0.52). The authors concluded that people with this disease have reduced exercise capacity and quality of life. They suggested that the walk test may be a useful substitute measure of peak exercise capacity and physical activity when cardiopulmonary exercise testing and activity monitors are unavailable. There was no healthy comparison group.

We wrote this plain-English summary from the full article with the help of AI, and a second AI model checked each sentence against the article. It is not the authors' wording; the abstract and the article are their own account.

What the study did and found

• Design: Observational (cross-sectional) study of exercise capacity, quality of life, physical activity and lung function
• Who was studied: 25 men with asbestos related pleural disease at Royal Prince Alfred Hospital, Sydney, Australia, November 2008 to August 2010. Of 28 men assessed, 3 were not included. Mean age was 71 (SD 6) years. Mean smoking history was 12 pack-years, and 6 had never smoked. Recruitment was through the Workers' Compensation Dust Diseases Board of New South Wales, respiratory physicians, support groups, unions and newsletters for returned servicemen. People with mesothelioma, or with discrete parietal pleural plaques as their only manifestation of dust exposure, were excluded.
• Exposure: The condition studied was asbestos-related diffuse pleural thickening and/or rounded atelectasis, diagnosed by a respiratory physician or the Dust Diseases Board Medical Authority. The article gives no fiber types, jobs or exposure levels.
• Main results:
  • In the 25 participants, mean six-minute walk distance was 76 (SD 11)% of predicted and mean peak work rate on the cycle test was 71 (SD 21)% of predicted. Mean walk distance was 486 (SD 68) metres.
  • Health-related quality of life was reduced across all domains of the St George's Respiratory Questionnaire. On this questionnaire a higher score means worse quality of life. The mean Total score was 23 (SD 15).
  • Six-minute walk distance correlated with peak work rate (r=0.58, p=0.002) and with peak oxygen uptake in ml/kg/min (r=0.53, p=0.006).
  • Six-minute walk distance was significantly correlated with the following: FVC % predicted (r=0.52), DLCO % predicted (r=0.50), daily METs (r=0.45), SGRQ Total (r=-0.57) and SGRQ Activity (r=-0.50). The correlations with daily steps (0.38) and daily energy expenditure (0.06) were not marked as significant.
  • Activity monitor data were unavailable for 2 participants, who wore it for less than the minimum three days because of skin irritation. The remaining 23 wore it for a mean (SD) of 6 (1) days.
  • In the better walk test, 44% of participants had a fall in oxygen saturation of 4% or more. Desaturation was greater during the walk test than the cycle test, with a mean difference of 3% (95% CI: 1 to 4), p less than 0.001.
  • Participants walked a mean of 13 metres (95% CI: 6 to 21) further on the second walk test than the first (p less than 0.001), and 80% walked further on the second test.
  • Reasons for stopping the cycle test: dyspnoea in 8 participants, leg fatigue in 10, and both in 7.
• The authors' conclusion: The authors concluded that people with asbestos related pleural disease have reduced exercise capacity and health-related quality of life. They also concluded that the six-minute walk test may be a useful surrogate measure of peak exercise capacity and physical activity levels when cardiopulmonary exercise testing and activity monitors are not available.
• Limitations the authors state:
  • No metabolic or ventilatory data were collected during the walk test, so these could not be compared directly with the cycle test.
  • People on long-term oxygen therapy were excluded, so the findings cannot be extended to them.
  • There was no healthy age-matched control group. Results were compared with previously published predicted values instead.
  • People with a smoking history were not excluded. The authors explained that excluding them would make the sample unrepresentative of the patient population.

Topics

The National Library of Medicine indexes this study under subjects our site covers: Asbestosis.

Medical terms in this study, explained in our Lexicon: Quality of Life, Six-Minute Walk Test, FEV1/FVC Ratio, Diffusing Capacity (DLCO).

Related studies

• Exercise training to improve exercise capacity and quality of life in people with non-malignant dust-related respiratory diseases — M.T. Dale, Z.J. McKeough, et al. (2015)
• Physical activity in people with asbestos related pleural disease and dust-related interstitial lung disease: An observational study — M.T. Dale, Z.J. McKeough, et al. (2015)
• Exercise training for asbestos-related and other dust-related respiratory diseases: a randomised controlled trial — M.T. Dale, Z.J. McKeough, et al. (2014)
• Health-related quality of life in patients with lung cancer: validation of the Mexican-Spanish version and association with prognosis of the EORTC QLQ-LC13 questionnaire — Ó. Arrieta, C. Núñez-Valencia, et al. (2012)
• Health-related quality of life and inflammatory markers in malignant pleural mesothelioma — S.C. Kao, J. Vardy, et al. (2013)
• Physical function and health-related quality of life in patients undergoing surgical treatment for malignant pleural mesothelioma — T. Tanaka, S. Morishita, et al. (2017)

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