Age related thymus decline impact inability of adults to restore immune function following HIV infection and leads to increased morbidity and frailty. We sought to investigate the relationship between thymus imaging detection and structural changes with immunometabolic markers, multi-morbidity, frailty, and quality of life (QoL) in men with HIV.
This was a cross-sectional observational study including 665 consecutive HIV patients attending routine cardiovascular risk assessment with coronary artery calcium by mean of thoracic CT scan. Thymus detection and structural characteristics were retrospectively evaluated using a semiquantitative score based on the percentage of thymus solid tissue component (grade 0=no solid tissue; 1=1-25%; 2=26-50%; 3=51-75%; 4=76-100%; 5=100% solid tissue). Frailty was measured with the frailty phenotype and a 37-item Frailty index.
665 HIV infected patients (81% males), median age 53 years and median CD4=730/μL and HIV-RNA<40 c/mL in 98.5% were included. The table describes relevant immunometabolic markers. Thymus detection was also associated with lower prevalence of hypertension, diabetes, cardiovascular disease, MM, frailty and impaired QoL. In a multivariate logistic model, independent predictors for thymus detection were: male gender (OR=0.46, 0.22-0.93, p=0.03), BMI (OR=0.86, 0.81-0.98, p=0.03), IVDU (OR=0.22, 0.08-0.52, p<0.01), Frailty (FI>=0.4) (OR=0.95, 0.92-0.99, p=0.02), HIV duration (residual after correction for age) (OR=0.8, 0.65-0.97, p=0.03) and impaired QoL (OR=2.5, 1.19-5.78, p=0.02) after correction by Age (years) (OR=1.15, 0.95-1.38, p=0.15). Given the association between thymus structural characteristics and age a secondary sensitivity analyses was performed matching all the thymus detected cases with a subset of age and sex matched thymus not detected controls from the same cohort (180 cases +180 controls) confirming association with frailty and QoL. The impact of thymus on frailty was confirmed including thymus structural changes as predictors of most frail individuals (FI>=0.4) in multivariate logistic regression (mild or higher, OR=0.3, 0.12-0.93, p = 0.04) after correction for HIV duration (residual) (OR=1.10, 1.02-1.20, p=0.01), CD4/CD8 (OR=1.4, 0.6-3.3, p=0.38) and HIV late presentation (OR=0.5, 0.19-1.4, p=0.18)
Thymus detection and structural changes are associated with immunometabolic disarrangements and clinical spectrum of aging in HIV patients.