This retrospective derivation-validation registry study assessed the prognostic value of complete blood count (CBC) parameters for a composite outcome of lung transplantation or death in consecutive ILD patients at tertiary referral centers. It included a derivation cohort (n=369, median follow-up 20 months) and an independent validation cohort (n=696, median follow-up 60 months).
Neutrophil count >5.6 K/μL was confirmed as an independent predictor of worse outcomes across most ILD subtypes in both cohorts (except CTD-ILD). Platelet count <149 K/μL also showed prognostic significance, though it was not an independent predictor in multivariate analysis.
- Retrospective registry design limits causal inference and may introduce selection bias toward tertiary-center patients. - CBC cutoffs were data-derived (Youden's index), which may not generalize to other populations. - CTD-ILD was an exception to the neutrophil finding, but subgroup sizes were not reported, limiting interpretation.
At ILD diagnosis, check a CBC: a neutrophil count above 5.6 K/μL independently signals higher risk of death or lung transplantation across most ILD types. Consider closer monitoring or earlier referral for advanced therapies in patients who cross this threshold — but note this threshold does not apply to CTD-ILD.
