TY - JOUR T1 - Reply: Not all HDL particles are equal in idiopathic pulmonary fibrosis JF - European Respiratory Journal JO - Eur Respir J DO - 10.1183/13993003.00151-2022 VL - 59 IS - 4 SP - 2200151 AU - Amisha V. Barochia AU - Scott D. Barnett AU - Nargues Weir AU - Stewart J. Levine AU - Steven D. Nathan Y1 - 2022/04/01 UR - http://erj.ersjournals.com/content/59/4/2200151.abstract N2 - We thank T. Yasuma and co-workers for their interest in our study about the association between small high-density lipoprotein particles measured by nuclear magnetic resonance spectroscopy (S-HDLPNMR) and clinical outcomes, including mortality, in idiopathic pulmonary fibrosis (IPF) [1]. We found that there was no significant difference in mean total HDLPNMR levels between the healthy volunteers and the validation cohort, or between the IPF patients (discovery and validation cohorts combined) and the healthy volunteers. We specifically did state that our study was not designed to identify biomarkers for IPF. Rather, we sought to explore the nature of any associations between serum lipids or lipoproteins and IPF severity or outcomes. To that end, we utilised correlations between these two groups of variables at the individual level rather than comparing group averages. Thus, even if there were significant differences in mean concentrations of serum high-density lipoprotein (HDL) particles between the IPF groups and healthy volunteers, individual values of serum HDL particles could not be employed to differentiate between IPF and non-IPF subjects based on our study.Small HDL particles are associated with both GAP as well as observed mortality/lung transplantation in IPF https://bit.ly/3oVWSHJ ER -