Frequency and characteristics of refractory dyspnea in idiopathic fibrosing interstitial pneumonia.

Patients with idiopathic fibrosing interstitial pneumonias (f-IIPs) mainly suffer from dyspnea. Refractory dyspnea, defined as persistent dyspnea despite optimal treatment, could be the signal to prescribe dyspnea relievers. We aimed to examine the prevalence and characteristics of refractory dyspnea in consecutive patients with f-IIPs. Refractory dyspnea was defined by an mMRC≥3 and also by a VAS dyspnea score≥2 at rest. The sensory and affective characteristics of refractory dyspnea (mMRC≥3) and associated quality of life (QoL) anxiety and depression were compared with non-refractory dyspnea (mMRC1-2) using the Multidimensional Dyspnea Profile (MDP), King's Brief Interstitial Lung Disease (KBILD) and Hospital Anxiety and Depression scale (HADs). We included 40 patients (24 men), aged 72 [68-79], FVC of 71 % [59-86] and DLCO 47 % [40-49]. Refractory dyspnea, was found in 38 % (95%CI:23-54) when defined by mMRC≥3 and in 67 % (95%CI:50-81) using a resting VAS dyspnea score ≥2. The agreement between the two definitions was low. Patients with refractory dyspnea (mMRC≥3) were more often women (60 % vs.28 %, p = 0.046), had a lower DLCO (24 % [22-43] vs.47 % [43-51], p = 0.014) and more frequently used oxygen (60 % vs.12 %, p = 0.003); they experience more intense air hunger (5/10 [3-6] vs.2/10 [0-5], p = 0.018)). No significant differences were observed in VAS, MDP, KBILD, or HADs scores between refractory and non-refractory dyspnea patients. Our results indicate a significant frequency of refractory dyspnea in patients with f-IIPs and an association with air hunger but no impact on the affective dimension of dyspnea, anxiety, depression and QoL, suggesting that the mMRC score might not accurately identify patients distressed by their breathlessness.