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  • Section Writer: Dr. Om J Lakhani
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• Q. What is the definition of Osteoporosis?

  • It is a disease characterized by
    • Low bone mass
    • Microarchitectural disruption
    • Increase skeletal fragility
    • Leading to an increase in fracture risk
  • WHO defines it as T score <-2.5

• Q. Give the WHO diagnostic criteria for osteoporosis?

  • Normal T score >-1.0
  • Osteopenia – T score -1.0 to -2.5
  • Osteoporosis – T score <-2.5
  • Severe osteoporosis- T score < -2.5 + Fragility fracture

• Q. What are the diagnostic criteria based on AACE 2020 guidelines ?

  • 1. T-score − 2.5 or below in the lumbar spine, femoral neck, total proximal femur, or 1/3 radius
  • 2. Low-trauma spine or hip fracture (regardless of bone mineral density)
  • 3. T-score between − 1.0 and − 2.5 and a fragility fracture of the proximal humerus, pelvis, or distal forearm
  • 4. T-score between − 1.0 and − 2.5 and high FRAX® (or if available, TBS-adjusted FRAX®) fracture probability based on country-specific thresholds

• Q. What are T-score and Z-score?

  • The T-score is the number of standard deviations of the BMD from the normal value of a young adult
  • The Z-score represents the number of standard deviations of the BMD from the normal value of the age, sex, race/ethnicity matched control subjects

• Q. When to use T-score and when to use Z-score?

  • T-score is used for the standard diagnosis of osteoporosis in postmenopausal and elderly men
  • Z-score is used to diagnose low bone mass or vulnerable bones in premenopausal women or young men.

• Q. What Z score cutoff is used for diagnosis of osteoporosis in Young premenopausal women?

  • If the Z score is < -2.0 the lady is said to have "low bone mass". Osteoporosis may not be a suitable term to use for premenopausal women, but a low bone mass term may be used as a substitute to "osteoporosis" and means the same diagnostically
  • In premenopausal women - the search for the secondary cause is a must

• Q. Is FRAX for India available ?

  • Yes
  • Please use the link https://www.sheffield.ac.uk/FRAX/tool.aspx?country=51

• Q. What is the cut-off for treatment based on the FRAX score ?

  • FRAX shows 10 years probability of fracture
  • The indications for intervention are :
    • 3% for hip fracture or
    • ≥ 20% for major osteoporotic fracture

• Q. If a patient has a fragility fracture, does she need a DEXA scan for the diagnosis of Osteoporosis ?

  • No
  • A fragility fracture is diagnostic of osteoporosis
  • It does not need a DEXA scan to prove the diagnosis

• Q. What is a fragility fracture ?

  • "A fragility fracture is usually a fracture sustained from force similar to a fall from a standing position or less that would not have occurred in healthy bone, excepting fractures of the skull, face, fingers, and toes."

• Q. What are the current screening guidelines for osteoporosis by NOF?

  • All women >/= 65 years
  • All men >/= 70 years
  • All between ages 50-69 years with risk factors for osteoporosis
  • Adults having fractures after 50 years
  • Those with low bone mass and RA
  • Those with low bone mass on Gc of dose predinisolone equivalents >/= 5 mg for >/= 3 months

• Q. What is the mortality rate following a hip fracture in postmenopausal women?

  • 2-year mortality rate in postmenopausal women following a hip fracture is 12-20%

• Q. Enlist the risk factors for Osteoporosis?

  • Advancing age
  • Rheumatoid arthritis
  • Current cigarette smoking
  • Excessive alcohol consumption
  • Glucocorticoid use
  • Family history of hip fracture
  • Rheumatoid arthritis
  • Previous fragility fracture
  • Other secondary causes
  • Hypogonadism
  • Early menopause
  • Malabsorption
  • IBD
  • CLD
  • Primary hyperparathyroidism

• Q. What is the indication for lateral X-ray in the elderly?

  • All men >80 years and women >70 years with BMD T score <-1.0
  • All men 70-79 years and women 65-69 years with T score <-1.5
  • Postmenopausal women and men >50 years with
    • Historical height loss > 4cm (>1.5 inch)
    • Prospective height loss >2 cm (0.8 inch)
  • Low trauma fracture
  • Recent or ongoing Glucocorticoid use

• Q. What are the preferred screening tests?

  • DEXA

• Q. What are the sites for DEXA for screening?

  • Hip and spine
  • In the elderly Hip alone is enough

• Q. Which hip should be measured, right or left?

  • Ideally at baseline both hips should be measured

• Q. Which specific sites are to be measured?

  • 1. Total Hip
  • 2. Femoral neck
  • 3. Lumbar spine L1-L4

• Q. When is BMD repeated if the initial BMD does not show osteoporosis?

  • Women > 65 years
  • Initial BMD <-2.0 – 2.5 at any site or having a risk factor for ongoing bone loss- every 2 years
  • Initial BMD <1.5 to -2.0 at any site – every 3-5 years
  • Initial BMD <1.0-  1.5 with no other risk factor – every 10-15 years

• Q. What are the arguments in favor of screening for osteoporosis?

  • BMD has a definite link with fracture risk
  • Treatment is available which can prevent fracture
  • Knowledge of risk will help improve compliance with lifestyle and treatment
  • It is a common disease with a high impact on morbidity and mortality
  • Screening tests are easily available

• Q. What are the arguments against screening?

  • BMD is not the only criteria that define the risk of fracture
  • If BMD Is normal- does it rule out the risk of fracture?
  • Cost of screening
  • Single measurement of BMD less important than serial measurements

• Q. For what duration of glucocorticoid use, should DEXA be done?

  • For post-menopausal women, if glucocorticoids are given for >3 months or anticipated to be given for >3 months, a DEXA must be done at baseline without fail

• Osteoporotic fracture risk assessment

• Q. What are the methods for assessment of osteoporosis fracture risk?

  • FRAX
  • BMD measurement
  • Assessment of bone microarchitecture (beyond BMD)

• Q.  How is bone microarchitecture assessed?

  • HR pQCT
  • Tetracycline labeled transiliac bone biopsy
  • Micro MRI
  • High-resolution MRI
  • Trabecular bone score – indirect marker

• [[FRAX]]

• Q. In FRAX, the Risk of fracture is expressed as absolute risk or relative risk?

  • It is expressed as an absolute risk of fracture in the next 10 years

• Q. FRAX is applicable for age group patients?

  • Patients between the age of 40-90 years

• Q. Which are the factors considered in FRAX?

  • Age
  • Sex
  • BMI
  • Parental fracture of the hip
  • Previous fracture (A previous fracture denotes more accurately a previous fracture in adult life occurring spontaneously, or a fracture arising from trauma which, in a healthy individual, would not have resulted in a fracture. Enter yes or no (see also notes on risk factors)
  • Current smoking
  • Alcohol - >/= 3 units/day
  • Rheumatoid arthritis
  • Glucocorticoid use – Prednisolone >5 mg for >3 months
  • Secondary osteoporosis
  • Femoral neck BMD

• Q. Which are factors included in secondary osteoporosis?

  • Type 1 diabetes
  • Hypogonadism
  • Premature menopause
  • PHPT
  • CLD
  • Malabsorption
  • Malnutrition
  • Uncontrolled hyperthyroidism
  • Osteogenesis imperfecta

• Q. What will the results give you?

  • 10-year risk of
    • Major osteoporotic fracture
    • Hip fracture
  • Each in percentage

• Q. Is FRAX for India available?

  • Yes
  • Please use the link https://www.sheffield.ac.uk/FRAX/tool.aspx?country=51

• Q. What is the bias of basing treatment based on FRAX?

  • Treatment based on FRAX will treat more older patients with higher T scores compared to younger patients with the lower T scores

• Q. What are the limitations of FRAX?

  • Limited to 4 ethnicities
  • Only takes into account Hip BMD and not lumbar or other BMD
  • Other cases it may underestimate the risk (see below)
  • All regions data not available

• Q. FRAX is used for which ethnicities?

  • Black
  • Hispanic
  • Asian
  • Caucasian

• Q. In which patients do FRAX underestimate the fracture risk?

  • Type 2 diabetics
  • Multiple fractures
  • Family history of non-hip fracture
  • High dose Gc >7.5 mg
  • Severe vertebral fractures
  • Low Lumbar BMD with normal hip BMD

• Q. Overall does FRAX underestimate or overestimate fracture risk?

  • Overall, FRAX underestimates future fracture risk
  • Also fall events and the risk of falls are not directly captured by FRAX

• Q. Which other fracture risk calculator also takes risk of fall into account?

  • Garvan Fracture risk calculator

• Measurement of BMD

• Q. What are the methods for measurement of  BMD?

  • DEXA
  • Peripheral DEXA
  • pQCT
  • Quantitative ultrasound

• Q. How much does fracture risk increase for every 1 SD fall in BMD T score?

  • 2 times increase risk

• Q. Where is peripheral QCT measured?

  • Forearm
  • Calcaneus
  • Finger

• Q. What are the advantages and disadvantages of pDEXA (Peripheral DEXA)?

  • Advantage- Portable
  • Disadvantage
    • Cannot be used for classifying based on the WHO model
    • Cannot be used for follow-up treatment

• Q. What parameters are measured using quantitative ultrasound (QUS)?

  • It does not measure BMD
  • But measures
    • SOS – speed of sound
    • Stiffness Index- SI
    • Quantitative ultrasound index
    • Broadband ultrasound attenuation

• Q. Is QUS a good fracture predictor?

  • Yes

• Q. What are the disadvantages of QUS?

  • WHO criteria are not based on QUS
  • It cannot be used to monitor therapy as it changes very slowly
  • It cannot be used for treatment decisions as no trials are based on it

• **pQCT **

• Q. What is measured in pQCT?

  • Volumetric BMD – in mg/cm3
  • DEXA measure in g/cm2

• Q. What is the biggest advantage of pQCT?

  • Measurement of Cortical and trabecular fractions of the bone
  • It is mainly a research tool at present since it is more expensive and more radiation is used

• Q. Can it be used for FRAX calculation?

  • Yes hip QCT adjusted for BMD can be entered into the FRAX data

• **Newer techniques **

• Q. What is [[TBS (Trabecular bone score)]]?

  • It is the trabecular bone score
  • It is a software addition to the DEXA machine
  • It gives the texture of the bone  which correlates with the bone microarchitecture
  • It can be used with FRAX

• Q. How do you interpret TBS?

  • High TBS values suggest a more homogenous texture of bone suggesting good bone microarchitecture and lower fracture risk
  • Low TBS suggests a higher fracture risk
  • This has been validated in several studies

• Q. What are the interpretation based on exact values?

  • TBS
    • ≥1.350 → Normal
    • 1.200-1.350 → Partially degraded microarchitecture
    • ≤1.200 → degraded microarchitecture

• Q. In which cases is TBS particularly useful?

  • It is a useful addition to FRAX, especially in cases where FRAX is likely to underestimate the fracture risk
  • Examples are [[Type 2 Diabetes mellitus]] and [[Primary hyperparathyroidism (PHPT)]]

• Q. What is the advantage of HR- pQCT?

  • Cell tells about the bone microarchitecture
  • micro MRI can give similar information

• Q. What is Hip structural analysis?

  • It takes data obtained from the DEXA to look at hip parameters
  • It measures Hip axis length which correlates with fracture risk  and other parameters like Neck shaft angle etc

• Skeletal site to measure

• Q.  Which are common sites for DEXA?

  • ISCD recommends
    • Hip
    • Lumbar
  • For assessment commonly
  • However, if they cannot be assessed – a distal radius can be used
  • Lumbar is less useful in the elderly who have degenerative disc disease and aortic calcification

• Q. Which are the 2 most important non-BMD risk factors for fracture?

  • Advancing age
  • Previous fracture

#update

• Q. Give the parameters which help to assess bone quality and bone quantity
  • Please see the flow chart below
  • 

References:

1. Camacho PM, Petak SM, Binkley N, Diab DL, Eldeiry LS, Farooki A, Harris ST, Hurley DL, Kelly J, Lewiecki EM, Pessah-Pollack R. American Association of Clinical Endocrinologists/American College of Endocrinology clinical practice guidelines for the diagnosis and treatment of postmenopausal osteoporosis—2020 update. Endocrine Practice. 2020 May 1;26:1-46
2. Abdalbary M, Sobh M, Elnagar S, Elhadedy MA, Elshabrawy N, Abdelsalam M, Asadipooya K, Sabry A, Halawa A, El-Husseini A. Management of osteoporosis in patients with chronic kidney disease. Osteoporosis International. 2022 Nov;33(11):2259-74.