Osteoporosis: An Update
/Here’s the RoshReview Question of the Week!
A 53-year-old postmenopausal woman has a BMI of 19 kg/m². She is a chronic smoker and is taking steroids for rheumatoid arthritis. She drinks four alcoholic beverages per day. Her T score is −2.1. What can be a side effect of the recommended medication for her?
Check to see if your answer is right at the links above!
One of our first episodes from December 2018 was about osteoporosis, referencing the now withdrawn ACOG PB 129. ACOG has made a major change in its clinical practice documents that you’ll notice going forward – for future publications, Practice Bulletins will now have the new name change to “Clinical Practice Guidelines,” reflecting their main purpose as guideline documents.
Committee Opinions will be split into two groups, known as “Clinical Consensus” and “Committee Statement” documents. There are also the categories of “Practice Advisories” and “Obstetric Care Consensus” documents.
ACOG’s new guideline nomenclature!
The first Practice Bulletin to get the CPG treatment is Osteoporosis. So let’s review CPG #1!
Background
Osteoporosis is a generalized loss of bone mass and decline in bone quality, leading to increased fracture risk.
8.2 million women >50 years old have osteoporosis (compared to 2 million men)
71% of fractures in osteoporotic persons occur in women
50% of women over 50 will have an osteoporotic fracture
Additional 27.3 million women have low bone mineral density (formerly known as “osteopenia”)
Unfortunately, only 24% of women aged 60 and older receive osteoporosis treatment in the year after a fracture.
Risk factors aside from female sex:
Age: as described above, particularly over age 50
BMI under 20 or body weight less than 127 lb
Smoking
Alcohol use (especially more than 3 drinks daily)
Parental history of hip/spine fracture
Conditions, disease, and medications associated with “secondary osteoporosis”
HIV/AIDS and antiretroviral drugs
Anorexia
Diabetes mellitus (T1 and T2)
Gastric bypass
Hyperparathyroidism
POI / premature menopause / Turner syndrome or use of Aromatase inhibitors, GnRH agonists, DMPA
Antiepileptic drugs
Chronic steroid use
And more!
Racial variation: white and Hispanic populations with highest fracture risk
However, Black patients and Hispanic patients are less likely than White patients to get DXA screening after a hip fracture and less likely to receive osteoporosis treatment when indicated.
Black women also have higher rates of 1 year mortality, destitution, and other major adverse events following a fracture compared to White patients.
Varying studies looking at this have suggested multifactorial reasons for this inequity, including healthcare practitioner bias, patient mistrust of the healthcare system, other social determinants of health, or some complex interplay of these factors.
Bone physiology
90% of bone mass is acquired during childhood and adolescence. Peak bone mass in adolescence has been correlated with later-life fracture risk!
Bone mineralization and buildup in puberty is modified and optimized by sex steroids, predominantly estrogen, in both young girls and boys. Peak density is achieved around age 19 in women, and 20.5 in men.
In adulthood, bone is comparatively in physiologic equilibrium -- the formation of new bone (facilitated by osteoblasts) comes at a rate equal to, or slightly surpassed by, bone resorption (facilitated by osteoclasts).
Over time, this begins to favor resorption more and more, and is part of aging.
The loss of estrogen seen in menopause triggers a time-limited rapid bone loss in women that is not seen in men, and there are countering views on whether this is a pathologic or physiologic process.
Age also plays a factor – an 80 year old patient is at much higher risk for fracture than a 50 year old patient with the same BMD.
Prevention strategies
In young patients, part of our well-patient counseling should be on prevention of osteoporosis.
Prevention boils down to physical activity and calcium/vitamin D supplementation
Activity
ACOG recommends routine aerobic physical activity and weight bearing exercise to maintain bone health and prevent bone loss.
Recommendation of CDC for 150-300 minutes/wk of moderate intensity, or 75-150 mins/wk of vigorous activity aerobic exercise (or some combination) advised.
Weight bearing exercises appear to show most benefit – specifically mentioned are free weights, resistance bands, jogging, stepping, and jump rope.
Advises that patients in menopausal transition and in menopause are intentional with exercise, as weight-bearing, high force exercise or high-intensity interval training (HIIT)-style exercise have demonstrated small but significant increases in BMD.
Tai chi in postmenopausal women gets special mention in improving balance, preventing falls, and may have beneficial effect on BMD and bone turnover.
Calcium and Vitamin D
ACOG recommends consumption of appropriate amounts of these nutrients
Calcium:
Age 19-50: 1000 mg
Age 50+: 1200mg
Vitamin D:
Up to 70: 600 IU
After age 70: 800 IU
Patients wth history of vitamin D deficiency may need additional
USPSTF and Endocrine Society do not recommend screening for vitamin D deficiency in asymptomatic adults (i.e., routine screening)
Diagnosis
Don’t just jump to your DXA! And to know who might benefit, an H&P are essential.
Height loss can be an indicator of asymptomatic vertebral fracture – consider doing vertebral imaging by Xray or DXA if:
a 0.8in (2cm) loss in height over 1-3 years, or
a loss of 1.5 in (4cm) since peak height at age 20
Risk assessment tools can identify patients who may benefit from screening, the most common of which is the FRAX score
This tool is useful to identify patients prior to a DXA who may be at high risk of fracture, and to identify patients after a DXA who may benefit from osteoporosis treatment (more on that later)
Recommendations for when to get a DXA:
DXA is recommended universally in women 65 or older
DXA is recommended prior to age 65 in postmenopausal patients who have a pre-DXA FRAX score indicating an 8.4% or greater risk of major osteoorotic fracture in the next 10 years –
This is equivalent to the 10-year risk of a 65-year old White woman without risk.
***NOTE*** this is lower than previous recommendation, which was 9.3%
Finally, ACOG suggests repeat DXA only in patients with initial testing near treatment thresholds, or if risk factors change significantly (i.e., started new glucocorticoid therapy).
Generally, this will be no sooner than 2 years after an initial screen.
For those of average risk, there is no consensus on whether or when repeat DXA should be performed.
Osteoporosis and low BMD are diagnosed using dual energy X-ray absorptiometry (DXA).
Osteoporosis is defined as a T-score of < - 2.5 standard deviations
Low BMD is defined as a T-score of -1 to - 2.5 standard deviations
The T-score is calculated by looking at an individual’s BMD measurements at hip or spine, compared to a mean for a healthy, young-adult reference population.
DXA will also report a Z-score, which compares an individual’s BMD versus the mean of the patient’s same age, sex, and ethnicity.
ACOG notes that further research is needed to explore the contributors to T and Z score differences based on race/ethnicity.
Osteoporosis can also be diagnosed by:
A history of a fragility fracture, including an asymptomatic vertebral fracture
A T score consistent with low BMD, and an increased risk of fracture as determined by a risk assessment tool such as the FRAX scale
Specifically, a >20% risk of major fracture, or >3% risk of hip fracture, in the next 10 years.
Treatment: Fall Prevention
ACOG spends a significant part of this document asking OB/GYNs to assess fall risk in patients with low BMD or osteoporosis.
Identifying impairments in mobility, medical conditions or medications that may sedate or impair balance or gait; environmental factors in the home (i.e., loose throw rugs, poor lighting) is imperative for fall risk
Also encouraging patients, particularly seniors, to engage in exercise to help reduce risk as we mentioned before!
Unlike in the old Practice Bulletin, the new CPG doesn’t focus on the treatment of osteoporosis. This likely reflects the fact that most OB/GYNs do not treat osteoporosis primarily – worth referring to endocrinology to prescribe and monitor these therapies.
However, familiarity is good to have, so here’s a few pointers from our previous podcast!
Bisphosphonates: suffix of -dronate. Demonstrated efficacy of reducing fracture risk 35-65%. Often limited therapy less than 5 years due to limited data on use beyond then. Weird side effects -- significant reflux or esophageal trauma (stand upright 30-60mins after taking med), osteonecrosis of the jaw -- these are fortunately rare, but testable.
Raloxifene: a SERM, has agonist effects on the bone and antagonist effects on breast and uterus, so good choice in patient with (risks of ) breast CA/uterine CA, with concomitant osteoporosis. Big side effect consideration is VTE -- consider carefully in someone with a history of stroke/PE/DVT.
Calcitonin, Denosumab, recombinant PTH: other options but not worth your time – you’ll be referring to an endocrinologist to consider that
Hormone Replacement Therapy (HRT): not approved for primary treatment of osteoporosis, but has been shown to reduce risk of fracture in peri/postmenopausal women by 33-36%, based on the WHI study. A reasonable adjunct to have for patients with low BMD and no other considerations/contraindications. We covered HRT a long time ago as well in this podcast with Dr. Eger!