IC 18: Approach to the Management of Osteoporosis Flashcards
What is osteoporosis characterised by?
- Low bone density
- Microarchitecture disruption (impaired mineralisation)
- Decreased bone strength
- Increased risk of fracture
How is bone resorption and formation in osteoporosis?
Bone resorption > bone formation
What causes the decrease in bone mass for osteoporosis?
- Age
- Menopause
- Low serum calcium
- Alcohol consumption
- Smoking
- Physical inactivity
- Medication use (glucocorticoid use, PPI)
- Secondary to other diseases
What is the clinical manifestations of osteoporosis?
- Asymptomatic
- Often undiagnosed until presented with fragility fracture (low-trauma) (usually don’t cause fracture in normal humans) (spine, hip, wrists)
What patients should be assessed for osteoporosis and associated risk?
- Post-menopausal women
- Men >= 65 year old
- Especially if risk factors present
What are the risk factors for osteoporosis and consequent fracture?
- Family history of osteoporosis or fragility fractures
- Previous fragility fracture
- Ageing
- Low body weight
- Height loss (>2cm within 3 years)
- Early menopause (45 years and younger)
- Certain meds (like prolonged corticosteroid use)
- Low calcium intake (<500 mg/day)
- Excessive alcohol intake
- Smoking
- Prolonged immobility
- History of falls
- Presence of diseases that can lower bone density or increase fracture risk like DM or any inflammatory rheumatic disease
What does the osteoporosis self-assessment tool for Asians (OSTA) reveal?
- High risk (>20) to consider DXA scan as the chance of finding osteoporosis is high
- Medium risk (0-20) to consider DXA scan if any other risk factor for osteoporosis is present
- Low risk (<0) to consider deferring DXA
How is a diagnosis for osteoporosis made?
- History of fragility fracture at vertebral, hip, wrist, humerus, rib or pelvis (occurs spontaneously or from minor trauma) OR
- Bone mineral density measurement using DXA hip and/or spine reveals that patient is likely osteoporotic
What does the bone mineral density (BMD) measurement using DXA hip and/or spine reveal?
- T-score < -2.5 SD means osteoporosis
- T-score -1 to -2.5 SD means osteopenia
- T-score >= -1 SD means normal bone density
What is the difference between T-score and Z-score of BMD measurement using DXA hip and/or spine?
- T-score compares BMD against a young adult
- Z-score compares BMD against expected BMD for the patient’s age and sex (Z-score >= -2 SD suggests coexisting problems that can contribute to osteoporosis)
What tests should be performed to exclude secondary causes of bone loss?
- Creatinine
- Full blood count
- Corrected calcium
- 25-hydroxy vitamin D
- Thyroid-stimulating hormone
- Erythrocyte sedimentation rate
- Alkaline phosphatase
- Serum phosphatase
- Spot urine calcium/creatinine ratio
- Serum total testosterone
What tool can be used to evaluate fracture risk?
Fracture risk assessment tool (FRAX)
When should anti-osteoporosis treatment be initiated?
- Major osteoporotic risk >= 20%
- Hip fracture risk > 3%
When is FRAX score usually used?
Hint: remember algorithm
- If T-score from DXA scan is between -1 to -2.5
- FRAX score can be used to estimate the fracture risk and to determine if treatment should be given or not
When are patients treated for osteoporosis?
- Patient presenting with fragility fracture
- Patient without fragility fracture but DXA BMD T-score of <= -2.5
- Osteopenic (DXA BMD T-score between -1 and -2.5) without a fragility fracture but with high fracture risk of FRAX score
What are the contraindications for oral bisphosphonate therapy?
- CrCl <30
- Hypocalcemia
- Oesophageal or gastric abnormalities
- Inability to stand/sit upright for >= 30 mins
- Aspiration risk
What are the contraindications for IV bisphosphonate (zoledronic acid)?
- CrCl <35
- Hypocalcemia
What are the side effects of bisphosphonate therapy?
- Osteonecrosis of jaw
- Atypical femoral
What is the treatment duration for bisphosphonates?
Oral: 5 years
IV: 3 years
Which osteoporosis medication has concerns in renal impairment patients?
- IV bisphosphonate not for CrCl <35
- Oral bisphosphonate, teriparatide and raloxifene not for CrCl < 30
What are the risk factors for osteonecrosis of the jaw on bisphosphonate therapy?
- Tooth extraction or other invasive dental procedure
- History of cancer, radiotherapy
- Poor oral hygiene
- Concommitant angiogenesis inhibitors, bisphosphonates, chemo, corticosteroids, denosumab
- Comorbids like anemia, coagulopathy, infection, preexisting dental or periodontal disease
What advice should be given for patients to prevent osteonecrosis of the jaw?
- Smoking cessation
- Avoid invasive dental procedures during bisphosphonate therapy
- Maintain good oral hygiene
How should management be done if patient has osteonecrosis of the jaw and atypical femoral fractures?
ONJ: discuss with dentist and consider discontinuing therapy
Atypical femoral fracture: discontinue
What should be checked prior to initiating therapy for osteoporosis?
- Serum calcium
- Vitamin D levels (>= 20-30 but < 50-100)
What lab parameters should be measured for a patient on bisphosphonate therapy?
- Serum creatinine
- Serum calcium
- Serum vitamin D level
What are the non pharm advice for patients with osteoporosis?
- Appropriate calcium intake (1000mg/day for 51 and old, 800mg/day for 19 to 50)
- Optimise vitamin D intake (51 to 70 years old 600 iu/day, >70 800IU/day)
- Advise on appropriate weight-bearing, muscle-strengthening and balance exercise
- Limit caffeine intake (<=2 cups)
- Advise on smoking cessation and appropriate alcohol intake (<= 2 cans or 2 cups)
- Educate on fall risk, home safety and footwear
- Educate about osteoporosis and fragility fractures and implications
What are the DDIs associated with taking serum calcium or serum vit D?
- Calcium: PPI, fibre, iron, tetracyclines, fluoroquinolones, bisphosphonates, thyroid supplementation
- Vit D: rifampin, anticonvulsants, cholestyramine, orlistat, aluminium-containing products
