Association between C-reactive protein and carotid plaque in mild-to-moderate idiopathic pulmonary fibrosis

An association between C-reactive protein (CRP) levels and carotid plaque has never been investigated in idiopathic pulmonary fibrosis (IPF). The aim of this study was to evaluate the extent of carotid atherosclerosis in mild-to-moderate IPF and to assess its relationship to serum CRP. This observational retrospective case–control study included 60 consecutive IPF patients (73.8 ± 6.6 years, 45 males) and 60 matched controls, examined between Sep 2017 and Jan 2019. All patients underwent CRP assessment and a carotid Doppler ultrasonography. CRP levels were significantly higher in IPF patients than controls (0.2 ± 0.09 mg/dl vs 0.09 ± 0.04 mg/dl, p < 0.0001). A total of 46 plaques were detected, with higher prevalence in IPF patients than controls (38 vs 8, p < 0.0001). On univariate logistic regression the main variables independently associated with carotid plaque were: age (HR 1.09, 95% CI 1.03–1.16, p = 0.006), hypertension duration (HR 1.05, 95% CI 1.01–1.09, p = 0.01), diabetes duration (HR 1.09, 95% CI 1.01–1.18, p = 0.03), LDL-cholesterol (HR 1.07, 95% CI 1.04–1.10, p < 0.0001) and finally CRP levels (HR 1.73, 95% CI 0.59–5.00, p < 0.0001). Multivariate logistic regression analysis revealed that LDL-cholesterol (HR 1.05, 95% CI 1.01–1.08, p = 0.009) and CRP levels (HR 1.43, 95% CI 0.39–5.19, p < 0.0001) retained statistical significance. Common carotid artery-intima media thickness was significantly correlated with CRP levels in IPF patients (r = 0.86). SerumCRP might represent both an early marker and a potential therapeutic target for carotid atherosclerosis in mild-to-moderate IPF.