The potential value of FRAX index and bone turnover markers to identify osteoporosis in COPD patients

Chronic Obstructive Pulmonary Disease (COPD) is associated with numerous extrapulmonary diseases including osteoporosis. The incidence of osteoporosis in COPD patients is high and its early detection would prevent significant associated morbidity. To determine the utility of Fracture Risk Assessment Tool (FRAX) index and bone turnover markers (BTM) for the diagnosis of osteoporosis in COPD patients. This is a pilot study of 50 COPD patients followed at a Pulmonary Service. Age, sex, pack-years of smoking status, lung function, FRAX index and BTM (betacrosslap, osteocalcin and N-terminal propeptide of type 1 procollagen [P1NP]) were recorded. Bone densitometry was performed on all patients, and was classified as healthy or osteoporotic according to WHO criteria. The potential utility of FRAX index and BTM was explored by ROC analysis. Patient characteristics are described in Table 1. Excluding densitometric values, the area under the curve (AUC) for major fracture and hip fracture was 0.72 and 0.73, respectively; and the AUC for betacrosslap, osteocalcin and P1NP were 0.70, 0.74 and 0.63, respectively (Figure 1). The FRAX index and BTM have potential value in the screening for the early diagnosis of osteoporosis in COPD patients. The completion of our study will allow the identification of a useful cutoff point for early screening.