Dr. Engel presented the case of a man in his early 70s who presented after a fall at home with a new hip fracture in the setting of osteoporosis.
What is Osteoporosis?
Osteoporosis is a common disease that is characterized by low bone mass/strength, microarchitectural disruption, and skeletal fragility which results in an increased risk of fracture. This is generally an asymptomatic condition until a fracture occurs.
Physiology
During development, bone mineral density increases with puberty and peak bone mass is achieved in early adulthood. Estrogen and testosterone play a key role in this process. Estrogen, for instance, has impact on osteoclast and osteoblast activity in both men and women. Near the end of puberty, it halts the resorption of bone and results in closure of the growth (epiphyseal) plates.
Bone mass begins to decline after menopause in women and after age 50 in men, although the rate of bone loss in men accelerates more after age 70 with the decline in testosterone levels.
Risk Factors for Osteoporosis
There are several risk factors for osteoporosis, specifically anything that increases the rate of osteoclastic activity or that decreases the result of osteoblastic activity. Specifically, hypogonadism or medications that promote bone loss are often to blame.
Assessment & Screening Guidelines
The following patients should be screened for osteoporosis:
-All Women > 65
-Post-menopausal women < 65 and men ages 50-69 with FRAX score > 9.3
FRAX = Fracture Risk Assessment Tool.
This is a calculator developed by the WHO that estimates the 10-year probability of hip fracture and major osteoporotic fracture (defined as a fracture of the hip, clinical spine, proximal humerus, or forearm) for untreated patients between ages 40 and 90 years
This tool uses easily obtainable clinical risk factors (sex, prior fracture, smoking history, steroid use, history of RA, etc.)
-Patients with radiographic findings suggestive of osteoporosis or vertebral deformity
-Patients with more than 3 months of glucocorticoids
-Patients with Primary hyperparathyroidism
Screening occurs with DEXA.
DEXA assesses the density of the vertebral and hip bones and compares the density to that of healthy young-adult sex-matched reference values.
The distal one-third of the radius can be used if you cannot measure the hip or vertebral bone density.
Provides you with a T-score: the T-score is based on the number of standard deviations above or below the mean reference value.
Osteopenia = a T-score between −1.0 and −2.5
Osteoporosis = T-score of −2.5 and below.
Severe osteoporosis = T-score of −2.5 or below with one or more fractures.
If screening for osteoporosis in women and men younger than 50 years, ethnic- or race-adjusted Z-scores should be used. These scores compare a patient's bone density with others of their same age and ethnicity. A Z-score of −2.0 or lower should be described as “low bone mineral density for chronologic age”, not osteoporosis or osteopenia.
Management
1. First, rule out secondary causes.
While most patients with osteopenia or osteoporosis have non-modifiable causes resulting in bone decline, some patients have secondary causes. Because management in these cases focuses on reversing the etiology, you should determine if any of these causes are present Get the following labs for the following reasons:
CBC (Rule out malignancy)
CMP (Check calcium levels, kidney function)
TSH (Rule out thyroid disorders)
25-hydroxyvitamin D (Vitamin D deficiency can result in bone loss).
Urine calcium (Screen for hypercalciuria)
2. Calcium and Vitamin D Supplementation
3. Bisphosphonates
Bisphosphonates work by inhibiting osteoclasts.
Check both Vitamin D and Calcium before starting (bisphosphonates can lead to hypocalcemia). Also, make sure to assess your patient's ability to swallow pills because esophagitis can develop!
Bisphosphonates cannot be used in those with eGFR <35.
Give these medications with calcium: 1000 mg/day if male 50 to 70 and 1200 mg/d for everyone else.
Side effects: Osteonecrosis of the jaw (rare), atypical femur fractures. Drug-holidays have been suggested to reduce the risk of these side effects in patients with low-risk osteoporosis who have been on therapy for 3 to 5 years with stable bone density.
4. Calcitonin
Only approved in women who are 5+ years postmenopausal.
200 U are administered via single daily intranasal spray. (SubQ form also available, used less frequently).
Use with caution ih patients who have an allergy to salmon, allergic rhinitis, or epistaxis.
5. Estrogen agonist and antagonists
Because of the risks, estrogen therapy should be limited to younger women with premature ovarian insufficiency OR postmenopausal women who need treatment for hot flashes or vaginal dryness.
Additionally, Raloxifine has been approved for the treatment of postmenopausal osteoporosis.
6. Parathyroid hormone (Teriparatide)
Used for treatment of osteoporosis in postmenopausal women and men who are at high risk for fracture (T-score of -3.0 or less or prior fracture on bisphosphonate therapy) or high risk of fracture due to long-time glucocorticoid use.
It is the only bone-building treatment option for osteoporosis.
Anabolic steroid that is administered by SubQ injection; it is approved for up to 24 months over a patient's lifetime. You then transition to bisphosphonates or denosumab.
7. RANK ligand inhibitors (Denosumab)
Approved for the treatment of osteoporosis in postmenopausal women who are at high risk of fracture.
Antiresorptive agent
Given by subcutaneous injection (60 mg every 6 months).
References
MKSAP 17- Calcium and Bone Disorders
Adler RA, El-Hajj Fuleihan G. Managing osteoporosis in patients on long-term bisphosphonate treatment: report of a Task Force of the American Society for Bone and Mineral Research. J Bone Miner Res. 2016 Jan;31(1):16-35.
Bischoff-Ferrari H A, Willett WC, Orav E J, et al. A pooled analysis of vitamin D dose requirements for fracture prevention. N Engl J Med. 2012 Jul 5;367(1):40-9.
Holick MF. Vitamin D deficiency. N Engl J Med. 2007 Jul 19;357(3):266-81.
National Osteoporosis Foundation. Clinician's Guide to Prevention and Treatment of Osteoporosis. Washington, DC: National Osteoporosis Foundation, 2014.
Qaseem A, Forciea MA, McLean RM, Denberg TD; Clinical Guidelines Committee of the American College of Physicians. Treatment of Low Bone Density or Osteoporosis to Prevent Fractures in Men and Women: A Clinical Practice Guideline Update from the American College of Physicians. Ann Intern Med. 2017 Jun 6;166(11):818-839.
Wolpowitz D, Gilchrest BA. The vitamin D questions: how much do you need and how should you get it? J Am Acad Dermatol. 2006 Feb;54(2):301-17.
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