Use of beta-2 agonists and risk of hip/femur fracture: a population-based case-control study

INTRODUCTION: Administration of beta-2 agonists decreased bone mineral density in rats. But the association between bronchodilators and fracture risk has not been studied in humans.

OBJECTIVES: To examine the association between use of beta-2 agonists and risk of hip/femur fracture.

METHODS: We conducted a population-based case-control study (6763 cases) in the Dutch PHARMO database. Current beta-2 agonist use was compared to never use. We adjusted for severity of the underlying respiratory disease and disease and drug history.

RESULTS: A hospitalisation for asthma/COPD in the year before index date increased risk of hip/femur fracture: crude OR 2.17 (95% CI, 1.41-3.34). Patients using higher doses of beta-2 agonists had increased risk of hip/femur fracture: crude OR 1.94 (95% CI, 1.41-2.66) for daily dosages of >or=1600 microg albuterol equivalent. The excess fracture risk reduced after adjustment for disease severity (1.46; 95% CI, 1.02-2.08) and after exclusion of oral glucocorticoid users (1.31; 95% CI, 0.80-2.15). Risk of hip/femur fracture was similar between users of beta-2 agonists, inhaled glucocorticoids and anticholinergics.

CONCLUSION: We found increases in the risk of hip/femur fracture in patients using higher doses of beta-2 agonists. However, the excess risk of hip/femur fracture substantially reduced after exclusion of oral glucocorticoid users and after adjustment for the underlying disease. Risk of hip/femur fracture was similar between users of beta-2 agonists, inhaled glucocorticoids and anticholinergics. The severity of the underlying disease, rather than the use of beta-2 agonists, may play an important role in the aetiology of hip/femur fractures in patients using beta-2 agonists.