by Diane L. Schneider M.D.
Karen, age 55, just had her first bone-density test.
The results indicated osteopenia. She wanted to know what she should do, and she asked the most common question that comes up in the wake of this diagnosis: “Should I be taking a medicine for my bones?”
What Is Osteopenia?
Osteopenia is a decrease in bone mass below normal, or a T-score on a DXA (dual-energy X-ray absorptiometry) bone-density test that is between –1.0 and –2.5, but it is not a disease. In fact, providers today generally use the term low bone density in place of osteopenia in an effort to disassociate the finding of low bone mass with disease.
Though it is not a disease, low bone mass is still an important finding because it is a risk factor for future fractures. It is estimated that a 50-year-old white woman has a 15 to 20 percent lifetime risk of hip fracture and a 50 percent risk of any fracture. Approximately 1.5 million fractures occur per year in US adults. The majority of fractures occur in postmenopausal women with low bone mass. The fracture rate is lower in those with osteopenia than with osteoporosis, but there are so many more people with osteopenia that the absolute number of fractures is greater.
Understanding Your Risk
For someone like Karen, who is wondering what to do with the diagnosis of osteopenia, the most important thing is actually to evaluate her risk of fracture, a process that factors in bone density as well as additional risk factors.
The fracture risk assessment tool (FRAX®), which was developed by the World Health Organization (shef.ac.uk/frax), incorporates results of the hip (femoral neck region) bone density with your personal risk factors to calculate your 10-year fracture probability. Results of DXA bone density plus fracture risk assessment assist in making better intervention decisions than would be made using DXA alone.
These are the risk factors in the FRAX model:
- Height and weight
- History of a previous fracture
- Hip fracture in your mother or father
- Current smoking
- Steroid use
- Rheumatoid arthritis
- Secondary causes of osteoporosis
- Alcohol use of three or more units a day (one unit equals 10 ounces of beer, a 1-ounce shot of liquor, or a 4-ounce glass of wine)
The 10-year probability of fracture is calculated for the categories of major osteoporotic fracture and hip fracture. The major osteoporotic fracture category comprises four types of fracture: forearm, shoulder, hip, and clinical spine (these are the ones that are associated with symptoms, most commonly pain). Karen’s 10-year probability of fracture (with a femoral neck bone-density T-score of –1.27 and no clinical risk factors for major osteoporotic fracture) is 5.6 percent; and for hip fracture alone, her 10-year probability is 0.4 percent. Using the FRAX tool, Karen’s calculated 10-year risk of major osteoporotic or hip fractures is quite low.
Although the FRAX tool uses only one skeletal site—the femoral neck—of measurement, the lumbar spine measurement should not be ignored. If the bone density at the lumbar spine is lower than at the hip, actual fracture risk may be higher than estimated by the FRAX score. Karen’s lumbar spine T-score of –1.10 was similar to the results of her femoral neck T-score.
The National Osteoporosis Foundation’s treatment guidelines for osteopenia, released in 2008, incorporate the FRAX tool. For a postmenopausal woman with low bone mass (T-score of –1.0 to –2.5), therapies approved by the US Food and Drug Administration (FDA) are recommended if the 10-year fracture probability for hip is 3 percent or greater or the 10-year fracture probability for major osteoporotic fractures is 20 percent or greater.
Based on these treatment recommendations, Karen’s lumbar spine bone mineral density, and no other contributing risks, she does not need to take any bone-specific medicines at this time. She should continue with a bone-healthy regimen that includes adequate calcium, vitamin D, and exercise. A repeat DXA would be recommended in two to three years.
In general, postmenopausal women in the upper part of this range (–1.0 to –1.5) should usually be reassured and monitored in two to five years, depending on their age. Women in the middle part of this range (–1.5 to –2.0) usually do not need pharmacologic treatment but should be monitored every two to three years. Women in the lower part of the range (–2.0 to –2.5) should be monitored every year or two and may be candidates for pharmacologic intervention, depending on their risk factors for fracture.
The National Osteoporosis Foundation’s treatment guidelines for using FDA-approved medicines for postmenopausal women and men 50 and over include the following:
- History of a hip or spine fracture
- Osteoporosis by T-score at the hip or spine
- Low bone mass (T-score of –1.0 to –2.5) and a 10-year fracture probability (FRAX score) for hip fracture of 3 percent or greater or for major osteoporotic fractures of 20 percent or greater
Therefore identifying women at the highest risk of fracture is a clinical decision point for initiating treatment with medication. Low bone density is a strong risk factor for fracture; however, a more comprehensive assessment of clinical risk factors is helpful to define absolute risk and to select individuals appropriate for treatment.
New risk assessment tools integrate risk factors with bone density to estimate your fracture risk. If you have low bone density, these valuable tools help as a starting point for your decision-making discussions with your doctor. Osteoporosis medicines should be reserved for use when your risk of fracture is high or you have already sustained a fracture.