Prognostic prediction in COVID-19 patients: a comprehensive analysis of gut microbiota and hematological biomarkers

This study investigates gut microbiota dynamics in COVID-19 patients and evaluates the prognostic potential of clinical hematological indicators. We collected 293 fecal samples from 225 confirmed COVID-19 cases (January-March 2023). After excluding samples with missing information, those from patients receiving Traditional Chinese Medicine, and those failing quality control, 169 samples from 169 unique patients were retained for 16S rRNA sequencing to assess gut microbiota composition and function in relation to disease severity, clinical scores (CURB65, qSOFA, PSI), and patient demographics. Results revealed significant changes in the microbiota, with critical cases showing reduced alpha diversity (Chao1, P < 0.01) and distinct beta diversity patterns compared to moderate/severe groups. Taxonomic profiling revealed significant microbiota changes associated with COVID-19 severity. Specifically, moderate cases exhibited an enriched abundance of Lachnospiraceae, whereas critical patients showed increased Streptococcaceae levels. Notably, Bacteroides abundance was significantly reduced in high-risk patients. Functional annotation further revealed that these taxonomic shifts were accompanied by distinct metabolic pathway disruptions, which correlated with disease severity progression. Concurrently, hematological markers (hematocrit, total bilirubin, albumin, sodium, hemoglobin) strongly correlated with disease progression. Our findings demonstrate that severe COVID-19 is associated with gut dysbiosis, which may exacerbate disease pathogenesis, and highlight the utility of blood biomarkers in predicting clinical outcomes, providing new insights for risk stratification and therapeutic strategies.