Carotid Intima–Media Thickness and Atherogenic Indices in Idiopathic Pulmonary Fibrosis: Evidence of Subclinical Atherosclerosis

Background: Idiopathic pulmonary fibrosis (IPF) is a progressive interstitial lung disease characterized by poor prognosis and accumulating evidence of systemic vascular involvement. Although cardiovascular comorbidities are recognized in IPF, the presence and extent of subclinical atherosclerosis are yet to be fully characterized. This study determined whether patients with IPF exhibit increased carotid intima–media thickness (CIMT) and altered atherogenic indices compared with healthy controls. Methods: This retrospective case–control study enrolled 117 patients with IPF diagnosed based on international guidelines and 104 age- and sex-matched healthy controls. All participants underwent comprehensive pulmonary function testing, the 6-min walk test (6MWT), laboratory evaluation (including lipid profiles), and bilateral carotid Doppler ultrasonography for CIMT measurement. Atherogenic indices, including the atherogenic coefficient, cholesterol ratio risk (CRR), and atherogenic index, were calculated. Dyspnea severity was evaluated using the visual analog scale (VAS). Results: Patients with IPF exhibited significantly higher CIMT (0.78 ± 0.12 mm vs. 0.68 ± 0.10 mm, p < 0.001) and CRR (4.12 ± 1.23 vs. 3.45 ± 0.98, p < 0.001) compared with controls. After adjustment for age, sex, cumulative smoking exposure expressed as pack-years, BMI, and controlled hypertension, IPF status remained independently associated with higher CIMT (adjusted β = 0.086 mm, 95% CI: 0.057–0.115; p < 0.001) and CRR (adjusted β = 0.482, 95% CI: 0.191–0.773; p = 0.001). Furthermore, patients with IPF had significantly lower HDL cholesterol levels and higher VLDL cholesterol levels. CIMT correlated negatively with 6MWT distance (r = −0.312, p = 0.001) and positively with VAS dyspnea scores (r = 0.287, p = 0.002). Conclusions: Patients with IPF showed higher CIMT and more unfavorable atherogenic profiles than healthy controls, and these associations persisted after adjustment for major vascular risk factors. The observed relationships between CIMT, functional capacity, and dyspnea severity suggest a potential association between IPF and subclinical cardiovascular involvement. Prospective studies are warranted to clarify the clinical relevance and prognostic implications of these findings.