Is COPD an independent predictor of osteoporosis?

Abstract

Patients with COPD have a high incidence of osteoporosis. DEXA scanning is the standard for the diagnosis of osteoporosis. The FRAX tool has ben developed to risk stratify the need to investigate osteoporosis in the general population, separating patients into low, intermediate and high risk. Patients with high FRAX should be considered for treatment without the need for Bone Mineral Density (BMD) while patients with an intermediate risk should have BMD measured and risk calculated and low risk patients need no investigation. . Aims: The aim of the study was to evaluate if FRAX is an accurate tool in identifying patients at risk in a COPD population. Methods: 105 patients with COPD attending a respiratory clinic were included in the study (average age 67, FEV1 59%, 38M). FRAX score was calculated from a questionnaire and classified as low, intermediate or high risk. Pulmonary function tests and DEXA results were acquired from case records. Results: The majority of the patients (65%) were in the low risk group while 23% and 12% fell into the intermediate and high risk groups. There was no significant difference in the FEV 1 in the three groups. 33 patients had DEXA scans prior to clinic, the BMD results are summarised in table 1. Conclusion: FRAX scoring predicted low BMD in the high risk group but did not discriminate between low (negative predictive value = 17%) and intermediate risk groups with similar proportions of low BMD, thus may have its limitations in patients with COPD. COPD is likely to be an independent predictor of osteoporosis although we didn9t identify a relationship between severity (FEV 1 ) and fracture risk.