Osteoporosis

Question 1

What is the MOST common osteoporotic fracture?

Answer 1

Vertebral b/c most weight bearing

Question 2

What is the MOST deadly osteoporotic fracture?

Answer 2

Hip b/c compromised vasculature and immobility

Question 3

What are fractures are associated with?

Answer 3

20% increase in mortality in 1 year (if hip fracture = 20% increase of death by 6 months).

Question 4

***What are the different methods of measuring BMD?

Answer 4

• **1. Dual Energy X-ray Absorptiometry (DXA) GOLD STANDARD
  2. Peripheral DXA (pDXA)
  3. Quantitative Computed Tomography (QCT)

Question 5

Other than being the GOLD STANDARD, what is DXA? Should this scan be repeated? ***Do you need a DXA scan to dx osteoporosis? What are the disadvantages?

Answer 5

• Measures bone mineral content and bone area (g/cm2)
• Most widely used method giving very precise measurements at clinically relevant sites
• Less value in repeat DXA scans (for older adults) (beneficial for younger adults d/t still having accelerated bone loss and premenopausal).
• ***You DO NOT need a DXA scan to diagnosis osteoporosis if you have all the clinical signs (previous fracture, age, etc.)
• Disadvantages: Large machine (not portable), More expensive than peripheral technologies, Uses ionizing radiation (though very low dose)

Question 6

What is a Peripheral DXA (pDXA)? What confounds the fracture risk prediction?

Answer 6

Portable instruments that uses same technology as DXA to measure BMD from:
• Forearm
• Calcaneus
• Finger
Evaluation of fracture risk prediction confounded by:
• Technical differences
• Variation in bone regions of interest
• Lack of standardized reference databases for calculating T-scores

Question 7

What is Quantitative Ultrasonography (QUS)?

Answer 7

• Does NOT measure BMD
• Measures transmission of ultrasound through accessible limb bones or reflectance of ultrasound waves from bone surface (commonly calcaneus)
• Parameters assessed: Broadband ultrasound attenuation, Speed of sound, Quantitative ultrasound index, Stiffness index
• Advantages: Lower expense, Portability, Lack of radiation exposure
• Disadvantages: No studies showing reduction in fracture risk for pt selected for therapy based on QUS measurement; Cannot be used to monitor response to therapy (changes are too slow).

Question 8

What is Quantitative Computed Tomography (QCT)?

Answer 8

• Measures volumetric BMD (in mg/cm3), most often at the spine
• QCT can isolate trabecular bone from its envelope of cortical bone.
• Advantages: Monitoring changes in BMD over time for patients with structural abnormalities of the spine precluding use of DXA
• Disadvantages: Expensive, Less reproducible, Higher radiation dose than DXA

Question 9

***What are the non-BMD risk factors?

Answer 9

-Advancing age
-Previous fractures (increases risk of any future fracture by 86%)
-Falls
-Glucocorticoid Therapy
-Family history of hip fracture (2x increase)
-Low body weight
-Vitamin D deficiency
-Current smoking or excessive alcohol
-Medications (anxiolytic, antidepressants, anticonvulsants, neuroleptics)
-Medical disease (d/t inflammation, malabsorption, renal excretion of Ca2+, or meds)
Ex: RA, lupus, IBD, celiac, bariatric surgery, cystic fibrosis, hyperthyroidism, hyperparathyroidism, DM, renal disease, leukemia/lymphoma, Parkinson’s, MS

Question 10

What are the guidelines for osteoporosis screening?

Answer 10

1. “The USPSTF recommends screening for osteoporosis in women aged 65 years or older and in younger women whose fracture risk is equal to or greater than that of a 65-year-old white woman who has no additional risk factors.” – Recommendation strength: B
2. FRAX(TM):
   • Estimates 10-year probability of hip fracture or major osteoporotic fractures combined (hip, spine, wrist or shoulder) for an untreated patient.
   • Based on large prospective study of men and woman in different world regions
   • By using femoral neck T-score or Z-score & obtainable clinical risk factors for fracture
   • USPSTF recommends risk assessment for postmenopausal females and females > 65 y/o
   • USPSTF “I” statement for older males: Current evidence is insufficient to assess benefits or harm of screening for men