Relationship between dyspnoea and related factors in patients with cancer: a cross-sectional study.

OBJECTIVES: Dyspnoea is a common and distressing symptom in patients with cancer. We aimed to analyse the association between dyspnoea and related factors and to estimate their causal relationship.

METHODS: A cross-sectional study was conducted. Patients with cancer with dyspnoea and a mean Numerical Rating Scale (NRS) of ≥3 over 24 hours were enrolled at 10 institutions in Japan from December 2019 to February 2021. The outcomes included dyspnoea, cough and pain NRS over 24 hours, Eastern Cooperative Oncology Group Performance Status, Hospital Anxiety and Depression Scale, Somatosensory Amplification Scale, opioids for dyspnoea and respiratory failure. Path analyses were conducted to estimate the direct and indirect paths with reference to dyspnoea and related factors.

RESULTS: A total of 209 patients were enrolled and 208 patients were included in the analysis. Cough worsened dyspnoea (β=0.136), dyspnoea increased emotional distress (β=1.104), emotional distress increased somatosensory amplification (β=0.249) and somatosensory amplification worsened cough (β=0.053) according to path analysis.

CONCLUSION: There may be a vicious circle among dyspnoea and related factors: cough worsened dyspnoea, dyspnoea increased emotional distress, emotional distress increased somatosensory amplification and somatosensory amplification worsened cough. When treating dyspnoea in patients with cancer, managing these factors aimed at interrupting this vicious circle may be useful.

TRIAL REGISTRATION NUMBER: UMIN Clinical Trials Registry (UMIN000038820).