Osteoporosis Self-Assessment Tool for Women

Risk stratify women for likelihood of osteoporosis


The osteoporosis self-assessment tool (OST)1 in women is a simple formula that predicts risk of osteoporosis for the patient based solely on current weight and age. Bone health is primarily determined by dual energy x-ray absorptiometry (DXA) scanning after women have been screened for possible disease. The original study that derived the OST score studied Asian women and had a 91% sensitivity and 45% specificity for identifying patients who would later be osteoporotic on DXA scanning. There have subsequently been multiple studies, validations, and other risk stratification tools made available to best identify patients who should undergo DXA; however, OST has been widely utilized for its simplicity.2
This is a rapid and useful bedside tool to help trigger further investigation into bone health for patients with an increased risk profile. The ranges here are based on the original derivation study, and notably other ranges have been proposed for the OST score itself depending on which demographic of women was studied.

A score is derived through:

OST = [weight (kg) - age (years)] divided by 5

OST Scores:

  • -20 to -4 are HIGH RISK
  • -4 to -1 are MODERATE RISK
  • -1 to 20 are LOW RISK


Koh L, Sedrine W, Torralba T, et al.


The Osteoporosis Self-Assessment Tool for Women calculator is created by QxMD.

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1. Weight?

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