Blood monocyte counts as a prognostic biomarker and predictor in Chinese patients with idiopathic pulmonary fibrosis

Abstract

ObjectivesWe sought to evaluate the prognostic value of blood routine parameters and biochemical parameters, especially inflammation-related biomarkers, and establish an inflammation-related prognostic model in Chinese patients with idiopathic pulmonary fibrosis (IPF).Material/methodsPatients diagnosed as IPF at Beijing Chaoyang Hospital and aged 40 years and older were consecutively enrolled from June 2000 to March 2015, and finally, a total of 377 patients were enrolled in the derivation cohort. The follow-up ended in December 2016. We used Cox proportional hazard model to calculate the hazard ratio (HR) and establish the prognostic model. The discrimination and calibration of the prognostic model were evaluated in an independent validation cohort enrolled from China-Japan Friendship Hospital between January 2015 and December 2019.ResultsMultivariate analysis revealed that patients with elevated monocyte-to-red blood cell count ratio (MRR) and monocyte counts showed increased risk of mortality. The clinical-physiological-biomarker (CPB) index and CPB stage we established in this study were a significant predictor, and the C-index for CPB index and CPB stage in the validation cohort was 0.635 (95% CI: 0.558–0.712) and 0.619 (95% CI: 0.544–0.694), respectively. Patients in CPB stage III had the poorest survival.ConclusionWe developed and validated a new inflammation-related prognostic model (CPB index and CPB stage) which was integration of age, gender, FVC (%, predicted), DLCO (%, predicted), Charlson Comorbidity Index, and blood monocyte counts. This prediction model exhibited strong ability in predicting mortality in Chinese patients with IPF.

Peripheral blood monocyte count and outcomes in patients with interstitial lung disease: a systematic review and meta-analysis

“…Monocyte counts were measured at varying timepoints, from within 30 days of diagnosis to up to 4 months within presentation to the ILD clinic. Varying monocyte counts were used in analyses; one study used the monocyte count of >0.24×10 9 cells·L −1 [ 20 ], one study used ≥0.6×10 9 cells·L −1 [ 13 ], one study used 0.6–<0.8×10 9 cells·L −1 [ 2 ], one study used ≥0.65×10 9 cells·L −1 [ 21 ], one study used >0.67×10 9 cells·L −1 [ 14 ], two used >0.9×10 9 cells·L −1 [ 17 , 18 ], five used ≥0.95×10 9 cells·L −1 [ 2 , 4 , 9 , 13 , 15 ] and one study used >1.0×10 9 cells·L −1 [ 19 ]. Two studies reported analyses using monocyte counts defined as a continuous variable [ 16 ] or in 1 sd increments [ 11 ].…”

“…Data on overall mortality, with or without transplantation, were available for nine out of 13 studies included in the systematic review. One study reported transplant-free survival [ 4 ], five studies determined all-cause mortality (specified at 1 year [ 2 , 13 ], 6 months [ 20 ] and an unspecified timeframe [ 17 , 19 ]) and three studies reported survival as the outcome [ 14 – 16 ]. One study reported a composite outcome of relative FVC decline ≥10% predicted or diffusing capacity of the lung for carbon monoxide ( D LCO ) decline ≥15% at 1 year, death or lung transplant.…”

“…Importantly, the included studies often had not adjusted for the same potentially confounding variables. Two out of seven studies adjusted for treatment status [ 2 , 14 ], while one study included treatment-naïve patients with IPF, but the timing of monocyte count measures in relation to drug treatments were not clear. Studies were observational retrospective cohort studies and of small to modest size.…”

“…Studies included in the systematic review reported on patients with IPF (n=7) [2,4,[13][14][15][16][17], indeterminate usual interstitial pneumonia (UIP) (n=1) [18], ILA (n=2) [11,19], fHP (n=1) [9], anti-melanoma differentiation-associated gene 5 (MDA5) positive dermatomyositis (DM)-ILD (n=1) [20] and a pooled cohort of fibrotic ILD (n=1) [21] (table 1). Most were retrospective cohort studies (one a post hoc analysis of randomised controlled trials [2]), except for two, which were prospective cohort studies [14,15]. All studies were published between 2019 and 2022.…”

“…All studies were published between 2019 and 2022. Four studies were from the United Kingdom [9,[17][18][19], two were multinational [11,13], two from in the United States [2,4], two from China [14,20], one from Australia [15] and one from Italy [16]. The number of participants ranged from 32 to 2067, for a total study cohort of 7684.…”