1. Il Trabecular Bone Score (TBS): un indice delle alterazioni della microarchitettura ossea predittivo per il rischio di frattura nel paziente HIV positivo Dr. Lorenzo Ciullini Sapienza Università di Roma Azienda Ospedaliera Sant’Andrea - Malattie Infettive – C.R. AIDS e MST Roma – Italia *The presenting author has no conflict of interest to report #297 – Infezioni da HIV

2. Background chronic infection decreased mortality  ageing HIV associated bone metabolism disorders (virus + immune activation + HAART) HIV infection in HAART era Aim of the study Prevalence of vertebral fractures Bone mineral density (BMD) alterations Bone microarchitecture evaluation Study of risk factors associated to vertebral fractures

3. Population Demographic characteristics Men [n/total (%)]131/149(87,9%) Women [n/total (%)]18/149(12,1%) menopausal status [n/total women (%)]2/1811% Age (years) [median (IQR)]44(37-52) Men (years) [median (IQR)]44(38-53) Women (years) [median (IQR)]40,5(36-44) HIV infection’s characteristics Duration of HIV infection (years) [median (IQR)]7(5-8) CD4 cells count (cell/μL)[median (IQR)]501(439-675) HAART-experienced patients [n/total (%)]140/14994% Duration of HAART (years) [median (IQR)]6(4-8)

4. Methods (1) Clinical interview, viro-immunological HIV markers, bone biochemical markers 10-year fracture probability with FRAX® algorythm Lateral thoracic and lumbar spine X-ray (vertebral fracture: height ratio reduction ≥ 20%) BMD measurement (DXA) at femoral neck, total hip and lumbar spine Lumbar Trabecular Bone Score (TBS) to evaluate bone microarchitecture

5. What’s TBS ? Methods (2) TBS is computed from texture of spine DXA examination file by a software (TBS iNsight ™ ) Trabecular Bone Score (TBS) is a parameter of bone quality related to bone microarchitecture and fracture risk (1) (2) TBS value is direct related to number of bone trabeculae and their connectivity; otherwise is inverse related to inter- trabecular distances TBS (1. Silva BC, 2014) (2. Boutroy S, 2013) TBS

6. Results (1) Characteristics of vertebral fractures No vertebral deformity [n (%)] 122(86,5%) Vertebral fracture [n (%)] 19(13,5%) Vertebral fractures prevalence stratified by TBS quartiles (1st-2nd vs 3rd-4th) No statistically signficant differences (p=0,510) p=0,025 osteoporosisosteopenianormal BMD and by BMD status

7. Results (2) Analysis of risk factors associated with vertebral fractures among HIV+ patients *Mann-Whitney test**multivariate logistic regression OR (p-value ** ) 1,025 (0,343) 1,128 (0,058) 0,004 (0,034) 141 patients Group F (with vertebral fractures) (n=19) median (IQR) Group NF (no vertebral fractures) (n=122) median (IQR) P-value* Age (years)48 (40-57)43 (37-51)0,043 BMI (kg/m²)27,9 (24-30)24,5 (22-26)0,012 Duration HIV infection (years)8 (5-10)6 (4-9)0,219 Duration HAART exposure (years)4 (2-8)5 (3-8)0,993 CD4 cells count (cell/μL)657 (564-747)575 (461-716)0,315 Vitamin D serum levels (ng/ml)15 (10-24)18 (13-24)0,329 BMD lumbar spine (g/cm²)0,998 (0,901-1,048)0,994 (0,903-1,085)0,673 BMD femoral neck (g/cm²)0,779 (0,704-0,866)0,765 (0,679-0,839)0,422 BMD total hip (g/cm²)0,962 (0,872-1,043)0,909 (0,833-0,995)0,283 TBS lumbar1,226 (1,172-1,333)1,337 (1,270-1,405)%0,001 FRAX® (%)4,3 (3-6)4,3 (2-6)77

8. High prevalence of vertebral fractures among HIV positive patients BMD is no associated to vertebral fractures independent association between TBS and vertebral fractures Further studies: higher HIV+ sample size and HIV- control group Conclusions bone microarchitecture deterioration: one of the major causes of vertebral fractures low BMD explains only partially bone fragility

9. Aknowledgments U.O.C. Malattie Infettive - C.R. AIDS e MST Prof. A. Pennica Dott.ssa D. Novarini Dott.ssa L. Gianserra Dott.ssa E. Teti U.O.C Medicina Interna 2 Prof. F. Conti U.O.C. Radiologia Prof. G. Argento Dott.ssa L. De Biasio