Serum Lipid Profile and Fibrinogen-Based Inflammatory Markers in Patients With Subjective Tinnitus

The goal of this study is to examine the interrelationships among hematological and biochemical markers of inflammation, fibrinogen levels, and subjective tinnitus.

A total of 147 patients presenting with subjective tinnitus not attributable to medical causes and 85 healthy controls matched for age and sex comprised the participants in this retrospective case-control study. All participants underwent laboratory tests, including a full blood count, fibrinogen, and a lipid profile, as well as otorhinolaryngologic examination, pure-tone audiometry, and tympanometry. Conditions excluded from the study were otologic disease, any degree of hearing loss, systemic metabolic disease, cancer, acute or chronic inflammatory disease, acoustic trauma, or being younger than 18 or older than 70 years. The following ratios were calculated from the laboratory data: fibrinogen/HDL (FHR), monocyte/HDL (MHR), HDL/non-HDL ratio, neutrophil-to-lymphocyte ratio (NLR), lymphocyte-to-monocyte ratio (LMR), neutrophil-to-monocyte ratio (NMR), platelet-to-lymphocyte ratio (PLR), systemic immune-inflammation index (SII), pan-immune inflammation value (PIV), and the ratios SII/HDL and PIV/HDL.

The results showed no significant difference in age or sex between the tinnitus group (average age 52.0.4±1.4 years; 59.1% women) and the control group (average age 47.6.1±1.1 years; 57.4% women). In the group with tinnitus, there was a notable increase in triglycerides and a decrease in HDL, along with an increase in fibrinogen (P<0.05). Although there were changes in neutrophil, lymphocyte, and monocyte counts across groups, no differences were found in derived indices such as FHR, LMR, and NMR; however, HDL/non-HDL, PLR, NLR, and MHR showed no significant differences.

Patients with idiopathic subjective tinnitus had an atherogenic lipid profile and a prothrombotic inflammatory milieu, as indicated by decreased HDL levels and increased triglycerides and fibrinogen. As supplementary markers, the fibrinogen/HDL ratio and some leukocyte-derived indices (LMR, NMR) can be helpful in determining whether tinnitus is caused by inflammation or vascular-metabolic factors. To elucidate causality and define clinically relevant cutoff values, prospective investigations are necessary.