Bisphosphonate Exposure and Risk of Subtrochanteric and Femoral Shaft Fractures in Asthma Patients

Pavankumar Kamat


October 28, 2021


  • In patients with asthma, exposure to bisphosphonate was associated with an increased risk of atypical subtrochanteric (ST)/femoral shaft (FS) fractures.

  • A higher cumulative dose and longer duration of bisphosphonate were associated with a higher risk of atypical ST/FS fractures.

Why this matters

  • The risks and benefits of bisphosphonate therapy should be carefully considered in consultation with patients with asthma.

Study design

  • A population-based nested case-control study included 69,074 patients with asthma, identified using data from the UK Clinical Practice Research Datalink and Hospital Episode Statistics databases.

  • Funding: James Trust Research Grant.

Key results

  • Of 69,074 patients with asthma, 67 reported atypical ST/FS fractures.

  • Overall, 27 (40.3%) patients with asthma received bisphosphonates vs 37 (14.2%) control participants, corresponding to an adjusted OR (aOR) of 4.42 (95% CI, 2.98-8.53; P<.0001).

  • The risk of atypical ST/FS fractures increased with the increasing number of bisphosphonate prescriptions between 61 and 130 prescriptions (aOR, 10.01; 95% CI, 2.90-34.8).

  • Higher bisphosphonate dose (16,000 mg) vs no use was linked to an increased risk of ST/FS fractures (aOR, 7.32; 95% CI, 1.73-30.83).

  • Use of bisphosphonate for ≤1 year (aOR, 3.85; 95% CI, 1.47-9.99) and ≥5 years (aOR, 7.67; 95% CI, 1.75-33.91) was associated with a higher risk of ST/FS fractures.

  • The risk of ST/FS fractures was higher in patients with asthma aged ≤80 years (aOR, 11.12; 95% CI, 3.35-36.91) vs ≥80 years (aOR, 2.78; 95% CI, 1.16-6.67).


  • Risk of diagnostic misclassification.  


Chalitsios CV, Shaw DE, McKeever TM. Risk of subtrochanteric and femoral shaft fractures due to bisphosphonate therapy in asthma: a population-based nested case-control study. Osteoporos Int. 2021 Oct 11 [Epub ahead of print]. doi: 10.1007/s00198-021-06197-7. PMID: 34635953  View abstract 

This clinical summary originally appeared on Univadis, part of the Medscape Professional Network.


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