What can we learn about breathlessness from population-based and administrative health data?

To review the findings and methodological strengths and limitations of studies of breathlessness using population-based or routinely collected data, including the novel methodology of the registry-based randomized controlled trial (R-RCT).

Breathlessness severe enough to restrict activity is common and increases in the last months of life both among elderly in the community and among patients in specialized palliative care. During the last week of life, risk factors for more severe breathlessness have been identified. Patients with advanced chronic obstructive or interstitial lung disease experience more breathlessness than patients dying from lung cancer. Breathlessness often remains unrelieved or only partially relieved at the end of life.

Data from population-based or health-administrative databases can inform on the epidemiology, associated factors and the potential impact of breathlessness. Potential strengths of these data are high precision and generalizability because of large, nonselective study populations with high completeness of follow-up of outcomes such as survival. Potential limitations include residual confounding and insufficient data quality which is unaffected by increasing the sample size. The R-RCT methodology combines strengths of randomization with those of large representative databases to evaluate effectiveness in clinical care.