RT Journal Article SR Electronic T1 Peripheral blood monocyte count and outcomes in patients with interstitial lung disease: a systematic review and meta-analysis JF European Respiratory Review JO EUROPEAN RESPIRATORY REVIEW FD European Respiratory Society SP 230072 DO 10.1183/16000617.0072-2023 VO 32 IS 169 A1 Bohyung Min A1 Amanda Grant-Orser A1 Kerri A. Johannson YR 2023 UL http://err.ersjournals.com/content/32/169/230072.abstract AB Background Peripheral blood monocyte counts have been associated with poor outcomes in interstitial lung disease (ILD). However, studies are limited by variable biomarker thresholds, analytic approaches and heterogenous populations. This systematic review and meta-analysis characterised the relationship between monocytes and clinical outcomes in ILD.Methods Electronic database searches were performed. Two reviewers screened abstracts and extracted data. Pooled estimates (hazard ratios (HRs)) of monocyte count thresholds were calculated for their association with mortality using ≥0.6×109 and >0.9×109 cells·L−1 for unadjusted models and ≥0.95×109 cells·L−1 for adjusted models, using random effects, with heterogeneity and bias assessed. Disease progression associated with monocytes >0.9×109cells·L−1 was also calculated.Results Of 3279 abstracts, 13 were included in the systematic review and eight in the meta-analysis. The pooled unadjusted HR for mortality for monocyte counts ≥0.6×109 cells·L−1 was 1.71 (95% CI 1.34–2.19, p<0.001, I2=0%) and for monocyte counts >0.90×109 cells·L−1 it was 2.44 (95% CI 1.53–3.87, p=0.0002, I2=52%). The pooled adjusted HR for mortality for monocyte counts ≥0.95×109 cells·L−1 was 1.93 (95% CI 1.24–3.01, p=0.0038 I2=69%). The pooled HR for disease progression associated with increased monocyte counts was 1.83 (95% CI 1.40–2.39, p<0.0001, I2=28%).Conclusions Peripheral blood monocyte counts were associated with an increased risk of mortality and disease progression in patients with ILD.Systematic review and meta-analysis demonstrate that peripheral blood monocyte counts are associated with increased risk of mortality and disease progression in ILD and ILA, indicating a potential role for blood monocytes as a prognostic biomarker. https://bit.ly/43IGuvC