POS0495 PREVALENCE AND RISK FACTORS OF OSTEOPOROSIS IN A BELGIAN COHORT OF LUNG TRANSPLANTATION CANDIDATES: THE PROGRES STUDY

Abstract

BackgroundFew data are available on the incidence of osteoporosis (OP) in end-stage pulmonary diseases, particularly in lung transplant candidates. Yet, organ transplantation can be accompanied by low bone mineral density (BMD) owing to immunosuppressive therapy, particularly with oral glucocorticoids (GCs) use.ObjectivesOur primary aim was to evaluate the prevalence and therapeutic management of OP in lung transplant candidates. Our second objective was to determine the risk factors associated with OP, including the type of respiratory disorder.MethodsWe included 198 patients (103 women) out of 388 screened for lung transplantation at our institution between January 1998 and December 2020. BMD, measured by Dual-energy X-ray absorptiometry (DXA, Hologic (t-m)) at the lumbar spine (LS), total hip (TH), and femoral neck (FN), vertebral fracture assessment (VFA), as well as previous major osteoporotic fracture (MOF), were recorded. We systematically collected well-recognized OP risk factors, along with other factors suspected of affecting BMD such as inhaled (i) GCs use, pulmonary function tests, hypoxemia and type of pulmonary disorder.ResultsOP, as defined by BMD values (T-score ≤ -2.5) and/or fragility fracture (FF), MOF and/or vertebral fractures (VF), was observed in 118 patients (59.6%). Among these patients, 54 (45.8%) had only a T-score ≤ -2.5, while 36 (30.5%) had only an FF, with predominant vertebral fractures (77.8%). The median age (IQR) of the study population was 58 years (53.0-62.0), and 59 years in OP patients (54.2-62.0). Mean T-scores (±SD) were -1.62±1.52 at the LS, -1.43±1.05 at the TH and -1.98±1.14 at the FN. Mean T-scores (±SD) in OP patients were -2.15±1.31, -1.87±0.93 and -2.44±1.03, respectively. The mean (±SD) ten-year probability of major osteoporotic fracture assessed by the FRAX algorithms (FRAX score) was 11.6±11.2 %, and the mean FRAX adjusted to GCs dose (±SD) was 12.0±12.1 %. Nighty-eight patients (49.5%) achieved intervention threshold adjusted for age based on FRAX results and 110 patients (55.6%) when FRAX was adjusted to GCs dose. Seventy-eight OP patients (66.1%) achieved the FRAX intervention threshold, of whom 53 (67.9%) received calcium and/or vitamin D and 33 (42.3%) had received an add-on therapy, mostly a bisphosphonate (n=23, 69.7%) or denosumab (n=4, 12.1%). Eighty-four OP patients (71.2%) achieved the FRAX intervention threshold adjusted to GCs dose, of whom 59 (70.2%) received calcium and/or vitamin D and 37 (44.5%) had received an add-on therapy, mostly a bisphosphonate (n=25, 67.6%) or denosumab (n=5, 13.5%). Thirty-six OP patients (30.5%), 18 patients (33.3%) with only a T-score ≤ -2.5 and 12 patients with only an FF, did not receive any medication. In total, 153 patients had a chronic obstructive pulmonary disease (COPD, 77.3%), 33 an interstitial lung disease (ILD, 16.3%) and 12 (6.1%) suffered from another pulmonary disease. Among OP patients, 102 had a COPD (86.4%), 12 an ILD (10.2%) and 4 (3.4%) suffered from another pulmonary disease.Lower BMI, iGCs use, COPD, reduced FVC and severely impaired FEV1/FVC ratio were associated with OP. GCs treatment was associated with FF, regardless of the daily dosage.ConclusionMost of lung transplant candidates were suffering from OP and one third suffered from FF. Thus, performing DXA and VFA should be recommended in lung transplant candidates in order to start adequate osteoporosis treatment before lung transplantation. This is even more important in COPD patients, as this population displays an increased risk of OP compared to other end-stage diseases. OP diagnosis is important in those patients as their risk of fracture is likely to increase after transplantation. The large proportion of untreated (or insufficiently treated) patients stressed the need to develop specific strategies in this field. Finally, controlling some risk factors is crucial for the management and prevention of OP, for instance by, at least, tapering the dosage of both oral and inhaled GCs.Table 1.REFERENCES:NIL.Acknowledgements:NIL.Disclosure of InterestsEdwin Curraj: None declared, François Carlier: None declared, Michel Dumonceaux: None declared, Patrick Evrard: None declared, Benoit Rondelet: None declared, Jean-Pierre Devogelaer: None declared, Yves Boutsen Speakers bureau: UCB, Grant/research support from: Viatris, Galapagos, Biogen, Amgen.