Disability and long-term breathlessness: a cross-sectional, population study.

Introduction: Disability, resulting from altered interactions between individuals and their environment, is a worldwide issue causing inequities and suffering. Many diseases associated with breathlessness cause disability but the relationship between disability and the severity of breathlessness itself is unknown.This study evaluated associations between disability using the WHO's Disability Assessment Schedule (WHODAS) 2.0 and levels of long-term breathlessness limiting exertion.

Methods: This population-based, cross-sectional online survey (n=10 033) reflected the most recent national census (2016) by age, sex, state/territory of residence and rurality. Assessments included self-reported disability (WHODAS 2.0 12-item (range 12 (no disability) to 60 (most severe disability)) assessed in 6 domains) and long-term breathlessness limiting exertion (modified Medical Research Council (mMRC) breathlessness scale; 0-4 (4-most severe)). Days in the last month affected by breathlessness were reported.

Results: Of respondents (52% women; mean age 45), mean total disability score was 20.9 (SD 9.5). 42% (n=4245) had mMRC >0 (mMRC1 31% (n=3139); mMRC2 8% (n=806); mMRC3,4 3% (n=300)). Every level of long-term breathlessness limiting exertion was associated with greater levels of disability (total p <0.001; each domain p <0.001). The most compromised domains were Mobility and Participation.In the last 30 days, people with severe breathlessness (mMRC 3-4): experienced disability (20 days); reduced activities/work (10 days); and completely forwent activities (another 5 days).

Conclusions: Disability should be in the definition of persistent breathlessness as it is systematically associated with long-term breathlessness limiting exertion in a grade-dependent, multidimensional manner. Disability should be assessed in people with long-term breathlessness to optimise their social well-being and health.