AB0992 Bone remodelling biomarkers in hiv infected patients
Authors: F. López, J. Loarce, C. Sobrino, J.L. Casado, M. Vázquez
Journal: Annals of the Rheumatic Diseases (2018)

<h3>Background</h3> Bone metabolism is an equilibrium of resorption and growth, maintained by many regulating factors. Several molecules have been identified that estimate bone turnover, being P1NP and b-CTX the most commonly used. Many studies have shown a relationship between their levels and metabolic bone disease, and possibly with risk of fracture. Human Immunodeficiency Virus (HIV) infected patients have lower bone mineral density (BMD), as documented on many studies. An increased incidence of fractures has been noted as well, probably due to predisposing factors related to HIV infection, apart from the traditional risk factors. <h3>Objectives</h3> To assess the relationship between mean values of bone biomarkers P1NP and b-CTX and incidence of vertebral fractures (VF) in a HIV infected population; and compare such values with those of a Spanish healthy population of reference. <h3>Methods</h3> We performed a cross-sectional study with HIV infected patients followed up in the Infectious Diseases Department of our centre from 2014 to 2016. P1NP and b-CTX values were determined and lumbar and thoracic spine radiographs made to assess presence of VF (Genant grading scale). Other clinical and demographic data were collected retrospectively. P1NP and b-CTX values in the presence (VF group) and absence of fractures (non-FV group) were compared. Mean values were also compared with the Camargo cohort, comprised of 1080 healthy postmenopausal Spanish women, used as reference. Statistical analysis were made with STATA. All patients signed and informed consent, previously approved by the Hospital's Ethics Comittee. <h3>Results</h3> A total of 144 patients were included, 38 were women with a mean age of 56,4 years old<sup>45–77</sup> and 106 men with mean age of 56,5 years old.<sup>45–86</sup> 27 of the patients had at least one VF. No statistically significant differences were found between P1NP mean levels in the FV and the non FV groups, with values of 45,30 ng/ml (±17,59 ng/ml) and 49.48 ng/ml (±32,92 ng/ml) respectively, (p=0.52). Mean levels of b-CTX were 0,38 ng/ml (±0,18 ng/ml) in the VF group and 0,43 ng/ml (±0,22 ng/ml) in the non-FV group, again without significant differences (p=0,35). Mean general b-CTX values in our population were 0,41 ng/ml (±0,21); 0,46 ng/ml (±0,20) in women and 0,39 ng/ml (±0,20) in men. Higher levels were found in HIV infected women than in the Camargo cohort (0,38±0,19 ng/ml), with statistical significance (p=0.03). Mean general P1NP values were 48.34 ng/ml (±29.47), 58.63 ng/ml (±32.9) in women and 44.95 ng/ml (±27.56) in men, with no statistically significant differences found when HIV infected women were compared with those of the Camargo cohort, (47,7±19,9 ng/ml) (p=0.06), although a trend towards higher levels in HIV infected women was observed. <h3>Conclusions</h3> In the present study no correlation between P1NP and b-CTX levels in HIV infected patients and incidence of vertebral fracture was found. P1NP and b-CTX mean values in HIV infected women in our study are higher than those of healthy postmenopausal Spanish women, which means a higher bone turnover in this population. More studies are needed to clarify the extent and clinical impact of this finding. <h3>Disclosure of Interest</h3> None declared