Health-related quality of life development in IPF versus other ILD – the HILDA study

Abstract

Background: Interstitial lung diseases (ILD) are a heterogenous group of mainly chronic lung diseases. For idiopathic pulmonary fibrosis (IPF) a high burden of disease was recently shown. The development of health-related quality of life (HRQL) of IPF patients compared to other ILD subtypes is sparsely investigated.

Methods: We measured generic HRQL (Visual Analog Scale (VAS)) and disease-specific HRQL (King’s Brief Interstitial Lung Disease questionnaire (K-BILD) and its domains breathlessness and activities, chest symptoms, psychological impact)) for 164 ILD patients at baseline and after 12 months. Important change were operationalized via minimally important difference (MID). Next, we adjusted HRQL change for sociodemographic variables and for FVC % predicted, baseline HRQL, and comorbidity burden.

Results: 25.0% of patients had IPF, 69.5% were male, median age was 66.5, baseline ØFVC % pred was 74.9 (SD:21.1) and Ø DLCO % pred was 44.8 (SD:16.5). 24.4% IPF vs 13.8% non-IPF patients deteriorated on K-BILD more than MID, and 39.0% vs 22% on VAS. 4.9% vs 14.6% improved on K-BILD, and 26.8% vs 22.0 % on VAS more than MID. Mean change in VAS (-3.1) was same in both groups, but K-BILD change was bigger for IPF (-3.0 vs. -0.2). Change in breathlessness domain differed significantly between IPF (-7.8) and non-IPF (-0.2), but change in the chest domain (-9.0 vs -2.8), and psychological impact (-1.47 vs 0.05) did not. There were no group differences in the adjusted model.

Discussion: HRQL deteriorates over time in all ILD patients. IPF patients show a faster decline, especially for breathlessness; yet differences disappear after adjustments. Thus worsening of HRQL might be underestimated in ILD in general.