The relationship between lipid biomarkers, inflammation and mortality in patients with tuberculosis

Tuberculosis (TB) remains one of the leading infectious causes of mortality worldwide. The interaction between lipid metabolism and immune response plays a crucial role in TB pathogenesis. High-density lipoprotein (HDL) and other lipid parameters have increasingly attracted attention for their associations with inflammatory markers and survival. This study aimed to investigate the relationship between serum lipid levels, inflammatory markers, and survival in patients with TB.

Data from TB and non-tuberculous mycobacteria (NTM) patients followed at Ege University Faculty of Medicine Hospital between January 2017 and January 2024 were retrospectively analyzed. Lipid profile [HDL, low-density lipoprotein (LDL), total cholesterol, triglycerides] and inflammatory parameters (C-reactive protein, erythrocyte sedimentation rate, ferritin, albumin, lymphocyte count) were recorded at diagnosis. Lipid levels were categorized into tertiles based on interquartile distribution. Groups were compared in terms of inflammatory response, clinical features, and survival.

A total of 148 patients were included in the study, comprising 127 TB and 21 NTM cases. Median age was 59.0 years [Interquartile range (IQR): 45.0-71.0] in the TB group and 64.0 years (IQR: 38.0-72.0) in the NTM group. Among TB patients, 62.2% were male (n= 79). Mortality among TB patients was 17.3% (n= 22). Patients with low HDL levels had significantly higher CRP and ferritin levels and lower albumin levels (p< 0.05). LDL and total cholesterol levels were similarly associated with CRP, albumin, and lymphocyte count. A significant association was observed between HDL levels and sex, with low HDL levels being more frequent among males (p< 0.001). Increasing HDL and triglyceride levels were associated with a trend toward improved survival (p= 0.063; linear trend p= 0.041). No significant associations were found between lipid levels and cavity formation, pulmonary versus extrapulmonary involvement, or acid-fast bacilli smear results (p< 0.05). In multivariable analysis, older age and lower serum albumin levels were independently and significantly associated with mortality (p< 0.005).

In patients with TB, serum lipid profiles show significant associations with systemic inflammatory markers. Low HDL levels were accompanied by a more pronounced inflammatory response. However, lipid biomarkers were not independently associated with mortality, suggesting that they may serve as complementary markers in the assessment of the inflammatory process rather than as direct prognostic indicators.