Objectives How effective are bone sparing medications (BSM)? Is bone mineral density (BMD) change related to other clinical variables?
Background Regular oral corticosteroids (OCSs) cause several side effects including BMD loss, occurring at varying rates in different patients.
Method Patients attending the specialist severe asthma clinic with two available bone densitometry scans since 2007 were identified and the hip and spine BMD change calculated. The cumulative steroid dose (pre and post first scan) and risk factors for osteoporosis were also recorded, including current bone protection.
Results Yearly hip BMD change and average cumulative steroid dose did not correlate for all patients (n = 59 Pearson = -0.083 p0.53) or for patients not on BSM (n = 27 Pearson = -0.26 p0.19). Yearly spine BMD change also did not correlate for all patients (n = 59 Pearson = 0.012 p0.19) or for patients not on BSM (n = 27 Pearson = -0.22 p0.28).
Body mass index (BMI) predicted a higher t-score on the first DXA scan; hip (n = 59) (Pearson = 0.59 p < 0.001) and spine (n = 59) (Pearson = 0.53 p < 0.001). However between scans, although not statistically significant, a higher BMI correlated with a greater decrease in BMD.
Analysing the effect of BSM (see figure: spine BMD change) showed spine BMD improved over time for patients taking a bisphosphonate (n = 59) p0.029. However when compared to patients on calcium/vitamin D or no BSM, patients on a bisphosphonate and calcium/vitamin D had a greater improvement ( + 1.5% average BMD change, p0.039) than patients on a bisphosphonate alone ( + 1.19% average BMD change, p0.21).
Conclusion OCS use causes a decrease in BMD which is greater in the spine. In this small population, cumulative steroid dose did not correlate to BMD change over time. Bisphosphonate and calcium/vitamin D demonstrated benefit in spine BMD between scans, whereas the benefit of bisphosphonate alone was not statistically significant.