To the Editors:
Nishiyama et al. 1 have nicely evaluated the role of dyspnoea in daily life as an independent prognostic marker in idiopathic pulmonary fibrosis (IPF). However, a few patient- and disease-related confounding factors should be kept in mind while evaluating this distressing symptom.
IPF is characterised by episodes of rapid deterioration secondary to acute exacerbations or infections 2, which may profoundly increase the severity of breathlessness. This feature has inadvertently not been considered by Nishiyama et al. 1 while prognosticating regarding patients with IPF, and has possibly led to inaccurate disease assessment. Serial evaluation of dyspnoea could have solved this issue and strengthened its prognostic role, but was not carried out during the study. In addition, factors such as age, sex and cultural background, disease complications such as pulmonary hypertension, and comorbid conditions such as asthma, anaemia, heart failure and renal failure may significantly alter dyspnoea level and lead to misinterpretation of disease survival. Severity of breathlessness in IPF may also be affected by the nutritional status (muscle mass) and level of daily activity (exercise tolerance) of the subjects, which were not discussed in this study.
Dyspnoea is a purely subjective parameter and can even be altered by a patient’s state of mind. More importantly, the patient’s perception of dyspnoea (and its grading) may change with involvement of other organ system or the presence of other symptoms about which the patient is more concerned.
Dyspnoea, although the most common symptom of IPF, is at times difficult to interpret. Grading of dyspnoea may provide an important clue regarding disease severity, but should never hinder a clinician from predicting disease outcome using proven objective parameters.
Serial evaluation of dyspnoea may be more appropriate than a single assessment in prognosticating IPF.
Statement of Interest
- ©ERS 2011