osteoporosis%20in%20women
OSTEOPOROSIS IN WOMEN
Osteoporosis is a progressive, systemic, skeletal disease characterized by decreased bone mass and microarchitectural deterioration of bone tissue leading to increased bone fragility and susceptibility to fractures.
The more risk factors (eg history of fracture, advanced age, comorbidities, etc) that are present, the greater the risk of fracture.

Osteoporosis%20in%20women Diagnosis

Assessment

Indications for Bone Mineral Density (BMD) Measurements

  • 2014 National Osteoporosis Foundation (NOF)    
    • Women ≥65 years; postmenopausal women >50 years with risk factors for fracture
  • 2015 International Society for Clinical Densitometry (ISCD)  
    • Women ≥65 years; postmenopausal women <65 years with a risk factor for low bone mass
    • Women during menopausal transition with risk factors for fracture
    • Women with the following indications:
      • A fragility fracture
      • A condition or who are taking medications associated with low bone mass/bone loss
      • Being considered for pharmacological therapy
      • Receiving treatment to monitor effect
      • Not on treatment in whom evidence of bone loss would require treatment 
  • 2018 US Preventive Services Task Force (USPSTF)
    • Women ≥65 years; postmenopausal women <65 years considered at increased risk for osteoporosis based on formal clinical risk assessment tool  
  • Osteoporosis Self-Assessment Tool for Asians (OSTA)
    • Can support detecting a postmenopausal woman’s risk for osteoporosis  

Glucocorticoid-induced Osteoporosis

  • BMD testing within 6 months of starting glucocorticoid therapy is performed in:
    • Adults <40 years old with history of osteoporotic fracture OR other significant osteoporosis risk factors
    • Adults ≥40 years old with FRAX™ with glucocorticoid dose correction
      • The risk generated with FRAX™ is increased by 1.15 for major osteoporotic fracture and 1.2 for hip fracture if glucocorticoid therapy is >7.5 mg/day

Some authorities recommend that patients >65 years with multiple risk factors be started on treatment for osteoporosis without bone mineral density measurements

World Health Organization (WHO) Fracture Risk Assessment Model (FRAX)

  • Developed to calculate the 10-year risk of osteoporosis fracture, with or without BMD values, based on individual factors (eg sex, age, ethnicity, family history, previous fracture, glucocorticoid treatment, smoking status, alcohol consumption, rheumatoid arthritis, low BMI)
    • Level of fracture probability will vary between countries
  • Useful in identifying among the group of patients with osteopenia those at higher risk of fracture
  • Limitations of FRAX include lack of detail on some risk factors (eg smoking, prior fracture, effects of glucocorticoids), non-inclusion of other known risk factors (eg biochemical markers, falls)

Fracture Risk Categories

  • Low risk: BMD T-score at both hip and spine >-1.0, and 10-year hip fracture risk <3%, and 10-year risk of major osteoporotic fractures <20%, with no prior hip or spine fractures
  • Moderate risk: BMD T-score at both hip and spine >-2.5, or 10-year hip fracture risk <3%, or risk of major osteoporotic fractures <20%, with no prior hip or spine fractures
  • High risk: BMD T-score at hip or spine of ≤-2.5, or 10-year hip fracture risk ≥3%, or risk of major osteoporotic fracture risk ≥20%, with a prior hip or spine fracture
  • Very high risk: BMD T-score at hip or spine ≤-2.5 with multiple spine fractures
CATEGORIES OF FRACTURE RISK IN GLUCOCORTICOID-TREATED PATIENTS
Fracture Risk Adults <40 Years Old Adults ≥40 Years Old
FRAX™* 10-year Risk of Major Osteoporotic Fracture FRAX™* 10-year Risk of Hip Fracture
Low No risk factors other than glucocorticoid therapy <10% ≤1%
Moderate Hip or spine BMD Z-score < -3 or rapid bone loss at a rate of ≥10% at the hip or spine in over 1 year and continuing glucocorticoid therapy at ≥7.5 mg/day for ≥6 months 10-19% >1% and <3%
High Previous osteoporotic fracture/s ≥20% ≥3%
Previous osteoporotic fracture/s
Hip or spine BMD T-score ≤ -2.5 in men ≥50 years old and postmenopausal women
*With glucocorticoid dose correction
Modified from: Buckley L, Guyatt G, Fink HA, et al. 2017 American College of Rheumatology Guideline for the prevention and treatment of glucocorticoid-induced osteoporosis. Arthritis Rheumatol. 2017 Aug;69(8):1521-1537.

Screening

Bone Mineral Density (BMD) Measurements

  • Bone mineral density measurements give an accurate reflection of bone mass and confirm diagnosis of osteoporosis
  • An excellent predictor of future fracture risk
    • For each standard deviation (SD) reduction in bone mineral density, there is approximately a two-fold increased risk of fracture
  • Recommended when results would affect management
  • Identifies patients for possible pharmacologic therapy
  • Used for therapeutic monitoring in patients with glucocorticoid-induced osteoporosis (GIOP)

Methods of BMD Measurement

  • Dual energy X-ray absorptiometry (DXA) of hip and spine
    • Gold standard
    • Diagnose osteoporosis with a hip and/or spine DXA BMD T-score of ≤ -2.5
    • Monitor therapeutic response based on BMD of the spine
    • Fracture risk assessment based on DXA measurement at the hip in patients with GIOP

    Bone Mineral Density T-SCORE

  • World Health Organization (WHO) Recommended Values* for Diagnosis of Osteoporosis
    Bone Mineral Density T-score (SD) Definition
    T ≥ -1 Normal
    -2.5 < T < -1 Osteopenia (low bone mass)
    T ≤ -2.5 Osteoporosis
    T ≤ -2.5 + fracture Severe/established osteoporosis

*Values are based on DXA
T-score: A comparison with young normal adult mean of the same sex

  • Quantitative Computed Tomography scan (QCT)
    • Used as an alternative technique when DXA is not available
    • Measures bone strength in the axial skeleton and volumetric bone density of the vertebra and hip
    • Has higher radiation dose compared to DXA
  • Trabecular Bone Score (TBS)
    • Evaluates microarchitectural texture of the bone
    • Highly sensitive in predicting fracture risk

Screening Methods (Not for Diagnosis or Monitoring)

  • Peripheral dual-energy X-ray absorptiometry (pDXA)
  • Computed tomography (CT)-based assessments: Peripheral QCT
  • Quantitative ultrasound densitometry (QUS) of heel, tibia, patella and other peripheral skeletal sites
If fracture is present: Physical exam, lab tests and radiologic tests should also be conducted to exclude underlying diseases that mimic, aggravate or cause osteoporosis eg secondary osteoporosis

Laboratory Tests

  • Complete blood count (CBC), erythrocyte sedimentation rate (ESR)
  • Renal function tests (eg BUN, creatinine)
  • Electrolytes [eg ionized calcium (Ca), phosphate, magnesium (Mg)]
  • Serum 25-hydroxyvitamin D, total protein, albumin, aspartate aminotransferase (AST), alkaline phosphatase
  • Urinalysis
  • Bone turnover markers
    • May be considered in the primary evaluation and follow-up of patients with osteoporosis 
    • Identifies patients at high risk for fractures
    • Used to evaluate efficacy and compliance to current treatment
    • Eg serum C-telopeptide (CTX), osteocalcin, N-terminal propeptide of type 1 procollagen (P1NP), tissue transglutaminase antibodies [immunoglobulin A and immunoglobulin G (IgA and IgG)], serum protein electrophoresis (SPEP)
  • Others (eg thyroid function as indicated, parathyroid hormone)

Imaging

Radiology

  • Scintigraphic bone studies, X-ray of lateral thoracolumbar spine or hip (as indicated)
    • Bone loss of >30% is seen as radiological osteopenia in plain X-rays

Vertebral Imaging

  • Recommended for the following:
    • Women >70 years with bone mineral density T-score <-1.0 at the spine, total hip, or femoral neck
    • Women 65-69 years with bone mineral density T-score <-1.5 at the spine, total hip, or femoral neck
    • Postmenopausal women with low-trauma fracture during adulthood, historical height loss (current height - peak height at 20 years) by >1.5 inches, prospective height loss (current height - recently documented height) by >0.8 inches, and/or currently or previously on long-term glucocorticoid treatment
    • Other bone mineral density measurements are unavailable

Diagnosis of Postmenopausal Osteoporosis

  • A T-score of ≤ -2.5 in the femoral neck, lumbar spine, total and/or 33% radius
  • Low-trauma fracture of the hip or spine (regardless of BMD)
  • Osteopenia or low bone mass with a fragility fracture of pelvis, proximal humerus or distal forearm
  • Osteopenia or low bone mass and high probability of FRAX™ fracture based on country-specific cutoffs
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